Re: Python to Julia code generator?
Le 2018-02-21 à 05:27, Chris Angelico a écrit : """If you find that your production code is too slow because you’re using mutual recursion between nine different languages, blame Dan Luu for this terrible idea.""" I have... NEVER gone as far as nine. That takes the cake. In fact, I don't recall ever going beyond three. At least, not in production... ChrisA Dude that is advanced stuff... :-) Etienne -- Etienne Robillard tkad...@yandex.com https://www.isotopesoftware.ca/ -- https://mail.python.org/mailman/listinfo/python-list
Re: Python to Julia code generator?
On Wed, Feb 21, 2018 at 9:04 PM, Steven D'Aprano wrote: > On Wed, 21 Feb 2018 04:13:56 -0500, Etienne Robillard wrote: > >> Hi, >> >> Would it be possible to build a Python to Julia code generator?? >> >> i'm interested to learn Julia and would love to have the capacity to >> embed or run native Python code in Julia.. > > http://blog.leahhanson.us/post/julia/julia-calling-python.html > """If you find that your production code is too slow because you’re using mutual recursion between nine different languages, blame Dan Luu for this terrible idea.""" I have... NEVER gone as far as nine. That takes the cake. In fact, I don't recall ever going beyond three. At least, not in production... ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Python to Julia code generator?
I found this: https://github.com/JuliaPy/PyCall.jl Looks pretty awesome already! :-) Thx E Le 2018-02-21 à 05:04, Steven D'Aprano a écrit : On Wed, 21 Feb 2018 04:13:56 -0500, Etienne Robillard wrote: Hi, Would it be possible to build a Python to Julia code generator?? i'm interested to learn Julia and would love to have the capacity to embed or run native Python code in Julia.. http://blog.leahhanson.us/post/julia/julia-calling-python.html -- Etienne Robillard tkad...@yandex.com https://www.isotopesoftware.ca/ -- https://mail.python.org/mailman/listinfo/python-list
Re: Python to Julia code generator?
On Wed, 21 Feb 2018 04:13:56 -0500, Etienne Robillard wrote: > Hi, > > Would it be possible to build a Python to Julia code generator?? > > i'm interested to learn Julia and would love to have the capacity to > embed or run native Python code in Julia.. http://blog.leahhanson.us/post/julia/julia-calling-python.html -- Steve -- https://mail.python.org/mailman/listinfo/python-list
Python to Julia code generator?
Hi, Would it be possible to build a Python to Julia code generator?? i'm interested to learn Julia and would love to have the capacity to embed or run native Python code in Julia.. Thx Etienne -- Etienne Robillard tkad...@yandex.com https://www.isotopesoftware.ca/ -- https://mail.python.org/mailman/listinfo/python-list
Re: c code generator from python
bhattacharya.kush...@gmail.com schrieb am 17.01.2018 um 12:03: > Is there any python framework or any tool as which can generate C code from > python code as it is . http://cython.org/ Stefan -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On Tue, 23 Jan 2018 17:43:18 +, bartc wrote: > It wouldn't be a satisfactory way of writing C programs. So, although > I'm not that big a fan of C syntax, it might be better to write C as C, > and Python as Python, to avoid confusion.) This. The fundamental reality is that `a + b` means different things in C and Python. Even if you limit yourself to integers and not arbitrary values (fractions, lists, strings, etc) the semantics are different: - in C, ints have a fixed number of bits and any addition which ends up out of range is undefined behaviour[1]; - while Python uses BigInts, overflow is impossible, and the only possible error is that you run out of memory and an exception is raised (although the addition can take an indefinite long amount of time). Often the difference doesn't matter... but when it does matter, it *really* matters. [1] If anyone thinks that it is addition with overflow, you are wrong. Some C compilers *may* use overflow, but the language strictly defines it as undefined behaviour, so the compiler can equally choose to set your computer on fire[2] if it prefers. https://blog.regehr.org/archives/213 [2] http://www.catb.org/jargon/html/H/HCF.html -- Steve -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On 23/01/2018 13:34, bartc wrote: Perhaps you simply want to use Python syntax to write C code? That would > be a different kind of translator. And a simpler one, as 'a=b+c' > translates to 'a+b+c;' in C. Or rather, 'a=b+c;' (I've written source to source translators, some of which could target C, but not Python to C. It would be feasible to write C code in a syntax that looks rather like Python, but it won't be real Python, and you can't run it as Python. It wouldn't be a satisfactory way of writing C programs. So, although I'm not that big a fan of C syntax, it might be better to write C as C, and Python as Python, to avoid confusion.) -- bartc -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On Wed, Jan 24, 2018 at 1:45 AM, wrote: > Hey Ally, > > Cython adds a big chunk of complexity to simple things. That's the problem. That's like saying "Unicode adds a big chunk of complexity to the simple task of translating a word from Japanese into Russian". No, it doesn't; the complexity is inherent in the problem. You cannot translate Python code into C code without either (a) reimplementing all of Python's semantics, as Cython does; or (b) drastically changing the semantics, such that even the very simplest of code might behave quite differently; or (c) manually reading through the code and writing equivalent C, which is what you might call "porting" or "rewriting". (Or possibly "prototyping", if the intention was always to transform it into C.) There is fundamentally NO easy way to translate code from one language into another and get readable, idiomatic code at the other end. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
Hey Ally, Cython adds a big chunk of complexity to simple things. That's the problem. Greetings. On 01/23/2018 01:54 PM, ally.m...@bankmail.host wrote: Have you tried cython ? On 01/23/2018 01:25 PM, kushal bhattacharya wrote: On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya wrote: Hi, Is there any python framework or any tool as which can generate C code from python code as it is . Thanks, Kushal hi, I have found nuitka as asuitable candidate but it seems that nuitka doesnt generate a simple C code which could be included as a C file in another program.Is there any alternative easier way regarding this? Thanks -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya wrote: > Hi, > Is there any python framework or any tool as which can generate C code from > python code as it is . > > Thanks, > Kushal ok so which python tool would be the best one which can be included and parameters can be passed to from another C code file -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
Id go this way too. Basic C is straightforward. I usually consider learning a new "thing " if the time to support potwntially combersome solution using existing methods justifies the effort. On Jan 23, 2018 09:01, "Ned Batchelder" wrote: > On 1/23/18 8:48 AM, kushal bhattacharya wrote: > >> On Tuesday, January 23, 2018 at 7:05:02 PM UTC+5:30, bartc wrote: >> >>> On 23/01/2018 13:23, kushal bhattacharya wrote: >>> On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya wrote: > Hi, > Is there any python framework or any tool as which can generate C > code from python code as it is . > > Thanks, > Kushal > yes i have but it generates a complex C code with python dependencies.I want to call the generated function from another C code but i Cant figure out how to do that >>> Because the translation isn't simply defined. >>> >>> I've just tried nuitka on the Python code 'a=b+c', and it generates 2400 >>> lines of C. The main purpose seems to be to generate a self-contained >>> executable corresponding to the Python, but generating first a C >>> equivalent then using a C compiler and linker. >>> >>> This equivalent code may just contain all the bits in CPython needed to >>> do the job, but bypassing all the stuff to do with executing actual >>> byte-code. But it also seems to do some optimisations (in the generated >>> C before it uses C compiler optimisations), so that if static types can >>> be inferred it might make use of that info. >>> >>> Perhaps you simply want to use Python syntax to write C code? That would >>> be a different kind of translator. And a simpler one, as 'a=b+c' >>> translates to 'a+b+c;' in C. >>> >>> -- >>> bartc >>> >> >> This is exactly what i meant to say.My goal is to translate the python >> code into its C equivalent with function name as it is. >> > > The best way to do that is to read the Python code, understand what it > does, and re-write it in C. You won't find an automatic tool that can do > the job you want. The semantics of Python and C are too different. > > --Ned. > -- > https://mail.python.org/mailman/listinfo/python-list > -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
You can look at SymPy code generator http://docs.sympy.org/latest/modules/utilities/codegen.html Perhaps this is exactly what you need. With kind regards, -gdg 2018-01-23 17:00 GMT+03:00 Ned Batchelder : > On 1/23/18 8:48 AM, kushal bhattacharya wrote: > >> On Tuesday, January 23, 2018 at 7:05:02 PM UTC+5:30, bartc wrote: >> >>> On 23/01/2018 13:23, kushal bhattacharya wrote: >>> >>>> On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal >>>> bhattacharya wrote: >>>> >>>>> Hi, >>>>> Is there any python framework or any tool as which can generate C >>>>> code from python code as it is . >>>>> >>>>> Thanks, >>>>> Kushal >>>>> >>>> yes i have but it generates a complex C code with python dependencies.I >>>> want to call the generated function from another C code but i Cant figure >>>> out how to do that >>>> >>> Because the translation isn't simply defined. >>> >>> I've just tried nuitka on the Python code 'a=b+c', and it generates 2400 >>> lines of C. The main purpose seems to be to generate a self-contained >>> executable corresponding to the Python, but generating first a C >>> equivalent then using a C compiler and linker. >>> >>> This equivalent code may just contain all the bits in CPython needed to >>> do the job, but bypassing all the stuff to do with executing actual >>> byte-code. But it also seems to do some optimisations (in the generated >>> C before it uses C compiler optimisations), so that if static types can >>> be inferred it might make use of that info. >>> >>> Perhaps you simply want to use Python syntax to write C code? That would >>> be a different kind of translator. And a simpler one, as 'a=b+c' >>> translates to 'a+b+c;' in C. >>> >>> -- >>> bartc >>> >> >> This is exactly what i meant to say.My goal is to translate the python >> code into its C equivalent with function name as it is. >> > > The best way to do that is to read the Python code, understand what it > does, and re-write it in C. You won't find an automatic tool that can do > the job you want. The semantics of Python and C are too different. > > --Ned. > -- > https://mail.python.org/mailman/listinfo/python-list > -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On 1/23/18 8:48 AM, kushal bhattacharya wrote: On Tuesday, January 23, 2018 at 7:05:02 PM UTC+5:30, bartc wrote: On 23/01/2018 13:23, kushal bhattacharya wrote: On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya wrote: Hi, Is there any python framework or any tool as which can generate C code from python code as it is . Thanks, Kushal yes i have but it generates a complex C code with python dependencies.I want to call the generated function from another C code but i Cant figure out how to do that Because the translation isn't simply defined. I've just tried nuitka on the Python code 'a=b+c', and it generates 2400 lines of C. The main purpose seems to be to generate a self-contained executable corresponding to the Python, but generating first a C equivalent then using a C compiler and linker. This equivalent code may just contain all the bits in CPython needed to do the job, but bypassing all the stuff to do with executing actual byte-code. But it also seems to do some optimisations (in the generated C before it uses C compiler optimisations), so that if static types can be inferred it might make use of that info. Perhaps you simply want to use Python syntax to write C code? That would be a different kind of translator. And a simpler one, as 'a=b+c' translates to 'a+b+c;' in C. -- bartc This is exactly what i meant to say.My goal is to translate the python code into its C equivalent with function name as it is. The best way to do that is to read the Python code, understand what it does, and re-write it in C. You won't find an automatic tool that can do the job you want. The semantics of Python and C are too different. --Ned. -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On Tuesday, January 23, 2018 at 7:05:02 PM UTC+5:30, bartc wrote: > On 23/01/2018 13:23, kushal bhattacharya wrote: > > On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya > > wrote: > >> Hi, > >> Is there any python framework or any tool as which can generate C code > >> from python code as it is . > >> > >> Thanks, > >> Kushal > > > > yes i have but it generates a complex C code with python dependencies.I > > want to call the generated function from another C code but i Cant figure > > out how to do that > > Because the translation isn't simply defined. > > I've just tried nuitka on the Python code 'a=b+c', and it generates 2400 > lines of C. The main purpose seems to be to generate a self-contained > executable corresponding to the Python, but generating first a C > equivalent then using a C compiler and linker. > > This equivalent code may just contain all the bits in CPython needed to > do the job, but bypassing all the stuff to do with executing actual > byte-code. But it also seems to do some optimisations (in the generated > C before it uses C compiler optimisations), so that if static types can > be inferred it might make use of that info. > > Perhaps you simply want to use Python syntax to write C code? That would > be a different kind of translator. And a simpler one, as 'a=b+c' > translates to 'a+b+c;' in C. > > -- > bartc This is exactly what i meant to say.My goal is to translate the python code into its C equivalent with function name as it is. -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On 23/01/2018 13:23, kushal bhattacharya wrote: On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya wrote: Hi, Is there any python framework or any tool as which can generate C code from python code as it is . Thanks, Kushal yes i have but it generates a complex C code with python dependencies.I want to call the generated function from another C code but i Cant figure out how to do that Because the translation isn't simply defined. I've just tried nuitka on the Python code 'a=b+c', and it generates 2400 lines of C. The main purpose seems to be to generate a self-contained executable corresponding to the Python, but generating first a C equivalent then using a C compiler and linker. This equivalent code may just contain all the bits in CPython needed to do the job, but bypassing all the stuff to do with executing actual byte-code. But it also seems to do some optimisations (in the generated C before it uses C compiler optimisations), so that if static types can be inferred it might make use of that info. Perhaps you simply want to use Python syntax to write C code? That would be a different kind of translator. And a simpler one, as 'a=b+c' translates to 'a+b+c;' in C. -- bartc -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya wrote: > Hi, > Is there any python framework or any tool as which can generate C code from > python code as it is . > > Thanks, > Kushal yes i have but it generates a complex C code with python dependencies.I want to call the generated function from another C code but i Cant figure out how to do that -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
What about Cython? On 01/23/2018 01:25 PM, kushal bhattacharya wrote: On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya wrote: Hi, Is there any python framework or any tool as which can generate C code from python code as it is . Thanks, Kushal hi, I have found nuitka as asuitable candidate but it seems that nuitka doesnt generate a simple C code which could be included as a C file in another program.Is there any alternative easier way regarding this? Thanks -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On Wednesday, January 17, 2018 at 4:34:23 PM UTC+5:30, kushal bhattacharya wrote: > Hi, > Is there any python framework or any tool as which can generate C code from > python code as it is . > > Thanks, > Kushal hi, I have found nuitka as asuitable candidate but it seems that nuitka doesnt generate a simple C code which could be included as a C file in another program.Is there any alternative easier way regarding this? Thanks -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
On 17/01/2018 11:04, kushal bhattacharya wrote: Hi, Is there any python framework or any tool as which can generate C code from python code as it is . What C code would you expect to see from this line of Python: a = b + c ? -- https://mail.python.org/mailman/listinfo/python-list
Re: python to C code generator
Hi, Have a look at Cython. Best 2018-01-17 12:04 GMT+01:00 kushal bhattacharya : > Hi, > Is there any python framework or any tool as which can generate C code from > python code as it is . > > Thanks, > Kushal > -- > https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list
python to C code generator
Hi, Is there any python framework or any tool as which can generate C code from python code as it is . Thanks, Kushal -- https://mail.python.org/mailman/listinfo/python-list
c code generator from python
Hi, Is there any python framework or any tool as which can generate C code from python code as it is . Thanks, Kushal -- https://mail.python.org/mailman/listinfo/python-list
how to write code generator for Isabelle by using pygments?
how to write code generator for Isabelle by using pygments? i am thinking to write a machine learning code to generate code by learning example from Isabelle code however, after google, not much information about this. -- https://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Mark Lawrence wrote: > On 17/07/2010 20:38, Mick Krippendorf wrote: >> >> If Java were *really* a multiple dispatch language, it wouldn't be >> necessary to repeat the accept-code for every subclass. Instead a single >> accept method in the base class would suffice. In fact, with true >> multiple dispatch VP wouldn't even be needed. > > Boilerplate, boilerplate everywhere, but not a beer to drink. That's Java for ya. class ASTNode: def accept(self, visitor): getattr(visitor, self.__class__.__name__)(self) class IfNode(ASTNode): ... # inherits generic accept method class ElseNode(ASTNode): ... # inherits generic accept method class PrettyPrinter: def IfNode(self, node): ... def ElseNode(self, node): ... Regards, Mick. -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On 17/07/2010 20:38, Mick Krippendorf wrote:
Karsten Wutzke wrote:
The visitor pattern uses single-dispatch, that is, it determines
which method to call be the type of object passed in.
Say, in Python, I have an object o and want to call one of it's methods,
say m. Then which of possibly many methods m to call is determined by
the type of o, and nothing else (at least without further magic) -
hence, it is single dispatch. The VP uses two single dispatch calls (one
being a callback) to accomplish double dispatching.
Java has a form of multiple dispatch through function overloading. In
fact, it's still single dispatch, because which of the targets
overloaded methods gets called is determined at compile time by the
staticly known types of the methods parameters, AKA the formal parameter
types.
Anyway. Although VP *uses* double dispatch, it does not necessarily rely
on function overloading. In Java the VP is most often implemented like this:
interface IASTNode {
void accept(IASTVisitor);
}
class IfNode implements IASTNode {
void accept(IASTVisitor visitor) {
visitor.visit(this);
}
}
class ElseNode implements IASTNode {
void accept(IASTVisitor visitor) {
visitor.visit(this);
}
}
interface IASTVisitor {
void visit(IfNode node);
void visit(ElseNode node);
...
}
class PrettyPrinter implements IASTVisitor {
public void visit(IfNode n) {
...
}
public void visit(ElseNode n) {
...
}
}
but it could as well be implemented like this:
interface IASTNode {
void accept(IASTVisitor);
}
class IfNode implements IASTNode {
void accept(IASTVisitor visitor) {
visitor.visitIfNode(this);
}
}
class ElseNode implements IASTNode {
void accept(IASTVisitor visitor) {
visitor.visitElseNode(this);
}
}
interface IASTVisitor {
void visitIfNode(IfNode node);
void visitElseNode(ElseNode node);
...
}
class PrettyPrinter implements IASTVisitor {
public void visitIfNode(IfNode n) {
...
}
public void visitElseNode(ElseNode n) {
...
}
}
If Java were *really* a multiple dispatch language, it wouldn't be
necessary to repeat the accept-code for every subclass. Instead a single
accept method in the base class would suffice. In fact, with true
multiple dispatch VP wouldn't even be needed.
Regards,
Mick.
Boilerplate, boilerplate everywhere, but not a beer to drink.
Hope everyone at EuroPython is having a good time.
Kindest regards.
Mark Lawrence.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Hello, Am 16.07.2010 09:52, Michele Simionato wrote: > [os.path.walk vs os.walk] > There is a big conceptual difference between os.path.walk and os.walk. > The first works like a framework: you pass a function to it and > os.path.walk is in charging of calling it when needed. The second works > like a library: os.walk flattens the hierarchical structure and then > you are in charge of doing everything you wish with it. > > os.walk is the Pythonic way, and you suggested to follow that > approach; for instance elementTree and lxml (libraries for parsing XML > data) work exactly that way. Actually one of the motivating examples for > the introduction of generators in Python was their use in flattening > data structure, i.e. exactly the pattern used by os.walk. The Visitor Pattern isn't about traversing, so they could as well have had an os.walk() that took a visitor object. Instead, it's about the untangling of unrelated stuff. Not the traversing vs. everything else - that's what iterators are for, like you said. But if you want to be able to add new types of operations without ever touching the code of the objects on which to apply those operations, then the VP is an easy way to accomplish things: class IfNode: def apply(self, operation): operation.handleIfNode(self) ... class ElseNode: def apply(self, operation): operation.handleElseNode(self) ... class PrettyPrinter: def handleIfNode(self, if_node): # print if_node pretty def handleElseNode(self, else_node): # print else_node pretty ... class Interpreter: def handleIfNode(self, if_node): # interpret if_node def handleElseNode(self, else_node): # interpret else_node ... class AST: def apply(self, operation): # apply operation to all nodes ... some_ast = ... some_ast.apply(PrettyPrinter()) some_ast.apply(Interpreter()) The traversing in AST.apply() is not really part of the pattern, it could also be done in the client code. The VP lives in the relation between the ...Node and the operation classes. It Encapsulates What Varies and helps to uphold the Open/Closed Principle, because to add new operations one does not need to touch the ...Node classes. It implements double dispatching in a single dispatch language. Regards, Mick. -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Karsten Wutzke wrote:
> The visitor pattern uses single-dispatch, that is, it determines
> which method to call be the type of object passed in.
Say, in Python, I have an object o and want to call one of it's methods,
say m. Then which of possibly many methods m to call is determined by
the type of o, and nothing else (at least without further magic) -
hence, it is single dispatch. The VP uses two single dispatch calls (one
being a callback) to accomplish double dispatching.
Java has a form of multiple dispatch through function overloading. In
fact, it's still single dispatch, because which of the targets
overloaded methods gets called is determined at compile time by the
staticly known types of the methods parameters, AKA the formal parameter
types.
Anyway. Although VP *uses* double dispatch, it does not necessarily rely
on function overloading. In Java the VP is most often implemented like this:
interface IASTNode {
void accept(IASTVisitor);
}
class IfNode implements IASTNode {
void accept(IASTVisitor visitor) {
visitor.visit(this);
}
}
class ElseNode implements IASTNode {
void accept(IASTVisitor visitor) {
visitor.visit(this);
}
}
interface IASTVisitor {
void visit(IfNode node);
void visit(ElseNode node);
...
}
class PrettyPrinter implements IASTVisitor {
public void visit(IfNode n) {
...
}
public void visit(ElseNode n) {
...
}
}
but it could as well be implemented like this:
interface IASTNode {
void accept(IASTVisitor);
}
class IfNode implements IASTNode {
void accept(IASTVisitor visitor) {
visitor.visitIfNode(this);
}
}
class ElseNode implements IASTNode {
void accept(IASTVisitor visitor) {
visitor.visitElseNode(this);
}
}
interface IASTVisitor {
void visitIfNode(IfNode node);
void visitElseNode(ElseNode node);
...
}
class PrettyPrinter implements IASTVisitor {
public void visitIfNode(IfNode n) {
...
}
public void visitElseNode(ElseNode n) {
...
}
}
If Java were *really* a multiple dispatch language, it wouldn't be
necessary to repeat the accept-code for every subclass. Instead a single
accept method in the base class would suffice. In fact, with true
multiple dispatch VP wouldn't even be needed.
Regards,
Mick.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On 07/16/2010 11:00 AM, Jean-Michel Pichavant wrote: > Karsten Wutzke wrote: >>> Yes, typo, I meant strictly. >>> >>> >> >> Damn, I mean strongly. At least not for identifying which methods to >> call depending on the type/s. >> >> Karsten >> > Stringly is the perfect combination of strictly and strongly. Nice one :) stringly typed sounds like "everything is a string" - doesn't Tcl do that ? ^^ -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Karsten Wutzke wrote: Yes, typo, I meant strictly. Damn, I mean strongly. At least not for identifying which methods to call depending on the type/s. Karsten Stringly is the perfect combination of strictly and strongly. Nice one :) JM -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Carl Banks, 16.07.2010 07:50: On Jul 15, 8:33 pm, Stefan Behnel wrote: The code I referenced is from the Cython compiler, and we use it to "do stuff" with the AST. The visitor pattern is actually a pretty common way to bind code in a single place that does a certain thing to different parts of a data structure. Without it, if you kept that code *inside* of the data structure, you'd have to spill the type specific parts all over your code. Ahh, so this aspect oriented programming is it. Never thought about it that way, but you have a point there. It's pretty much the same idea as AOP, but without any of those huge and feature drooling code injection frameworks. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On Jul 15, 7:58 pm, Karsten Wutzke wrote:
> Hello,
>
> this is obviously a Python OO question:
>
> Since Python isn't stringly typed, single-dispatch isn't available per
> se. So is the "double-dispatch" Visitor pattern, which is usually used
> in OO systems to implement code generators. So, what is the de facto
> method in Python to handle source code generation?
>
> Karsten
You ask about code generation and you already had answers in that
area, but let me talk a bit about a simpler topic, traversing a
hierarchical file system. I think this is relevant (even if not
answering your question) if you want to get familiar with the Python
way. In the old days, the way to traverse a file system was through
the os.path.walk function. Here is what the docs say (from
http://docs.python.org/library/os.path.html):
"""
os.path.walk(path, visit, arg)
Calls the function visit with arguments (arg, dirname, names) for each
directory in the directory tree rooted at path (including path itself,
if it is a directory). The argument dirname specifies the visited
directory, the argument names lists the files in the directory (gotten
from os.listdir(dirname)). The visit function may modify names to
influence the set of directories visited below dirname, e.g. to avoid
visiting certain parts of the tree. (The object referred to by names
must be modified in place, using del or slice assignment.)
"""
As you see the documentation make explicit reference to the visitor
pattern.
However a note below says:
"""
This function is deprecated and has been removed in 3.0 in favor of
os.walk().
"""
In other word, the visitor pattern is *not* the Pythonic way to solve
this
problem. The Pythonic way is to use os.walk, which converts the nested
structure in a flat structure. From the docs
(http://docs.python.org/library/os.html):
"""
This example displays the number of bytes taken by non-directory files
in each directory under the starting directory, except that it doesn’t
look under any CVS subdirectory:
import os
from os.path import join, getsize
for root, dirs, files in os.walk('python/Lib/email'):
print root, "consumes",
print sum(getsize(join(root, name)) for name in files),
print "bytes in", len(files), "non-directory files"
if 'CVS' in dirs:
dirs.remove('CVS') # don't visit CVS directories
"""
There is a big conceptual difference between os.path.walk and os.walk.
The first works like a framework: you pass a function to it and
os.path.walk
is in charging of calling it when needed. The second works like a
library:
os.walk flattens the hierarchical structure and then you are in charge
of
doing everything you wish with it.
os.walk is the Pythonic way, and you suggested to follow that
approach;
for instance elementTree and lxml (libraries for parsing XML data)
work
exactly that way. Actually one of the motivating examples for the
introduction of generators in Python was their use in flattening
data structure, i.e. exactly the pattern used by os.walk.
The message is stop thinking like in Java and start using idiomatic
Python. We are here to help.
Michele Simionato
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On Jul 15, 8:33 pm, Stefan Behnel wrote: > Carl Banks, 16.07.2010 01:14: > > > > > > > Around these parts, we consider the main use of most Design Patterns > > to be to work around limitations of other languages. Visitor Pattern > > is probably the worst example of it. > > > In Python it's completely unnecessary (at least in its boilerplate- > > heavy incarnation as used in C++), and the fact that Python isn't > > strongly typed, as you put it, is exactly the reason why. > > > Say you have a bunch of unrelated types that define a calculate > > method, you have a variable x that could be any of these types. > > Here's how you would do that in Python: > > > x.calculate() > > > Bam, that's it. Visitor Pattern in Python. You don't have to create > > a bunch of homemade dispatching boilerplate like you do in C++. > > Well, you can do that in every OO language. It's not what the visitor > pattern is there for, though. > > The code I referenced is from the Cython compiler, and we use it to "do > stuff" with the AST. The visitor pattern is actually a pretty common way to > bind code in a single place that does a certain thing to different parts of > a data structure. Without it, if you kept that code *inside* of the data > structure, you'd have to spill the type specific parts all over your code. Ahh, so this aspect oriented programming is it. I see your point, Visitor Pattern isn't necessary to work around the "can't easily polymorph unrelated types" limitation, but could still be necessary to work around "can't easily dispatch on methods not part of the class" limitation. So, ok, Visitor Pattern maybe isn't the worst one. My bad Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Karsten Wutzke writes: > Since Python isn't stringly typed, single-dispatch isn't available per > se. So is the "double-dispatch" Visitor pattern, which is usually used > in OO systems to implement code generators. So, what is the de facto > method in Python to handle source code generation? A minute of web surfing found this: http://chris-lamb.co.uk/2006/12/08/visitor-pattern-in-python/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Carl Banks, 16.07.2010 01:14: Around these parts, we consider the main use of most Design Patterns to be to work around limitations of other languages. Visitor Pattern is probably the worst example of it. In Python it's completely unnecessary (at least in its boilerplate- heavy incarnation as used in C++), and the fact that Python isn't strongly typed, as you put it, is exactly the reason why. Say you have a bunch of unrelated types that define a calculate method, you have a variable x that could be any of these types. Here's how you would do that in Python: x.calculate() Bam, that's it. Visitor Pattern in Python. You don't have to create a bunch of homemade dispatching boilerplate like you do in C++. Well, you can do that in every OO language. It's not what the visitor pattern is there for, though. The code I referenced is from the Cython compiler, and we use it to "do stuff" with the AST. The visitor pattern is actually a pretty common way to bind code in a single place that does a certain thing to different parts of a data structure. Without it, if you kept that code *inside* of the data structure, you'd have to spill the type specific parts all over your code. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On Jul 15, 11:45 am, Karsten Wutzke wrote: > On 15 Jul., 20:28, Thomas Jollans wrote: > > > On 07/15/2010 07:58 PM, Karsten Wutzke wrote: > > > > Hello, > > > > this is obviously a Python OO question: > > > > Since Python isn't stringly typed, > > > I expect this is an innocent typo, and you mean strictly. > > > > single-dispatch isn't available per se. So is the "double-dispatch" > > > Visitor pattern, > > Yes, typo, I meant strictly. > > > > > > > Wait, what? > > First of all, python is strictly typed in that every object has exactly > > one type, which is different from other types. So you can't do "1"+2, as > > you can in some other languages. > > > Anyway, this is interesting: Tell me more about how Python's dynamic > > nature makes it impossible to do whatever you're trying to do. I'm > > baffled. What are you trying to do, anyway? > > > > which is usually used > > > in OO systems to implement code generators. So, what is the de facto > > > method in Python to handle source code generation? > > > WHOA! Now if that isn't a Gedankensprung. Also, I'm still very far from > > your train of thought, apparently: Now, the thing that code generators > > probably share is that they write code to files. It depends on what I'm > > trying to do of course, but I expect there's a good chance that if I > > wrote a code generator in Python, it wouldn't be particularly > > object-oriented at all. > > Well, I'm most experienced in OO, so writing OO in Python seems like > the way to start with Python. The visitor pattern uses single- > dispatch, that is, it determines which method to call be the type of > object passed in. I did some reading and it turned out that Python > can't do it without some tricks (function decorators and 3rd party > code). For what I'm doing, I can't, or rather don't want to rely on > 3rd party code (that has reasons). Thus, the visitor OO pattern must > be replaced by some other way. Oh brother. Around these parts, we consider the main use of most Design Patterns to be to work around limitations of other languages. Visitor Pattern is probably the worst example of it. In Python it's completely unnecessary (at least in its boilerplate- heavy incarnation as used in C++), and the fact that Python isn't strongly typed, as you put it, is exactly the reason why. Say you have a bunch of unrelated types that define a calculate method, you have a variable x that could be any of these types. Here's how you would do that in Python: x.calculate() Bam, that's it. Visitor Pattern in Python. You don't have to create a bunch of homemade dispatching boilerplate like you do in C++. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On 15/07/2010 18:58, Karsten Wutzke wrote: Hello, this is obviously a Python OO question: Since Python isn't stringly typed, single-dispatch isn't available per se. So is the "double-dispatch" Visitor pattern, which is usually used in OO systems to implement code generators. So, what is the de facto method in Python to handle source code generation? Karsten I'm baffled. Not by what you mean by stringly, but What feature of Python stops you writing the three parts of the visitor pattern: IIRC you need: A tree walker that creates the visitor and walks the tree calling node.visitFrom(visitor) on each one in the required order. The visitfrom(aVisitor) routines in each node type that calls aVisitor.visitedMyNodeType(self) where MyNodeType is, naturally different for each node type! All the def visitedNodeType(aNode): routines in visitor to generate the code. Simples! No? :) Ian -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On 15/07/2010 18:58, Karsten Wutzke wrote: Hello, this is obviously a Python OO question: Since Python isn't stringly typed, single-dispatch isn't available per se. So is the "double-dispatch" Visitor pattern, which is usually used in OO systems to implement code generators. So, what is the de facto method in Python to handle source code generation? Karsten I'm baffled. Not by what you mean by stringly, but What feature of Python stops you writing the three parts of the visitor pattern: IIRC you need: A tree walker that creates the visitor and walks the tree calling node.visitFrom(visitor) on each one in the required order. The visitfrom(aVisitor) routines in each node type that calls aVisitor.visitedMyNodeType(self) where MyNodeType is, naturally different for each node type! All the def visitedNodeType(aNode): routines in visitor to generate the code. Simples! No? :) Ian -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
MRAB, 15.07.2010 21:33:
Stefan Behnel wrote:
Karsten Wutzke, 15.07.2010 20:45:
Well, I'm most experienced in OO, so writing OO in Python seems like
the way to start with Python. The visitor pattern uses single-
dispatch, that is, it determines which method to call be the type of
object passed in.
Well, then do that. Put the types into a dict and map them to the
functions to call, then call the function through the dict. That's a
pretty common way to do dispatching.
Note, that I have an hierarchical object structure which I want to
iterate over, so using OO looked natural to me. If there's a better
approach, I'm all ears.
You speak in riddles, but my guess is that your problem is that you
don't want to dispatch mechanism to match only exact types but also
subtypes. No problem, just build your dict incrementally and add new
types as they come in. See this file for an example:
http://hg.cython.org/cython-devel/file/tip/Cython/Compiler/Visitor.py
Another variation: the dispatch table starts with entries for certain
types then it adds subtypes on demand:
def visit(self, obj):
try:
handler = self.dispatch_table[type(obj)]
except KeyError:
for disp_type, disp_func in self.dispatch_table.items():
if isinstance(obj, disp_type):
self.dispatch_table[type(obj)] = disp_func
handler = disp_func
else:
raise RuntimeError("Visitor does not accept object: %s" % obj)
return handler(obj)
Well, yes, that's basically what the code behind the above link does,
except that it follows the type hierarchy correctly to find the closest match.
Stefan
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Karsten Wutzke web.de> writes: > So, what is the de facto method in Python to handle source code generation? Take a look at the NodeVisitor class in the ast module in python 2.6+. The visitor pattern is implemented in the python standard library. Matt -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Stefan Behnel wrote:
Karsten Wutzke, 15.07.2010 20:45:
Well, I'm most experienced in OO, so writing OO in Python seems like
the way to start with Python. The visitor pattern uses single-
dispatch, that is, it determines which method to call be the type of
object passed in.
Well, then do that. Put the types into a dict and map them to the
functions to call, then call the function through the dict. That's a
pretty common way to do dispatching.
Note, that I have an hierarchical object structure which I want to
iterate over, so using OO looked natural to me. If there's a better
approach, I'm all ears.
You speak in riddles, but my guess is that your problem is that you
don't want to dispatch mechanism to match only exact types but also
subtypes. No problem, just build your dict incrementally and add new
types as they come in. See this file for an example:
http://hg.cython.org/cython-devel/file/tip/Cython/Compiler/Visitor.py
Another variation: the dispatch table starts with entries for certain
types then it adds subtypes on demand:
def visit(self, obj):
try:
handler = self.dispatch_table[type(obj)]
except KeyError:
for disp_type, disp_func in self.dispatch_table.items():
if isinstance(obj, disp_type):
self.dispatch_table[type(obj)] = disp_func
handler = disp_func
else:
raise RuntimeError("Visitor does not accept object: %s"
% obj)
return handler(obj)
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Karsten Wutzke, 15.07.2010 21:00: Yes, typo, I meant strictly. Damn, I mean strongly. At least not for identifying which methods to call depending on the type/s. I think you meant "statically typed". http://c2.com/cgi-bin/wiki?StronglyTyped http://www.c2.com/cgi/wiki?StaticTyping Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
Karsten Wutzke, 15.07.2010 20:45: Well, I'm most experienced in OO, so writing OO in Python seems like the way to start with Python. The visitor pattern uses single- dispatch, that is, it determines which method to call be the type of object passed in. Well, then do that. Put the types into a dict and map them to the functions to call, then call the function through the dict. That's a pretty common way to do dispatching. Note, that I have an hierarchical object structure which I want to iterate over, so using OO looked natural to me. If there's a better approach, I'm all ears. You speak in riddles, but my guess is that your problem is that you don't want to dispatch mechanism to match only exact types but also subtypes. No problem, just build your dict incrementally and add new types as they come in. See this file for an example: http://hg.cython.org/cython-devel/file/tip/Cython/Compiler/Visitor.py Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On 07/15/2010 08:45 PM, Karsten Wutzke wrote: > On 15 Jul., 20:28, Thomas Jollans wrote: >> On 07/15/2010 07:58 PM, Karsten Wutzke wrote: >> >>> Hello, >> >>> this is obviously a Python OO question: >> >>> Since Python isn't stringly typed, >> >> I expect this is an innocent typo, and you mean strictly. >> >>> single-dispatch isn't available per se. So is the "double-dispatch" Visitor >>> pattern, >> > > Yes, typo, I meant strictly. > >> Wait, what? >> First of all, python is strictly typed in that every object has exactly >> one type, which is different from other types. So you can't do "1"+2, as >> you can in some other languages. >> >> Anyway, this is interesting: Tell me more about how Python's dynamic >> nature makes it impossible to do whatever you're trying to do. I'm >> baffled. What are you trying to do, anyway? >> >>> which is usually used >>> in OO systems to implement code generators. So, what is the de facto >>> method in Python to handle source code generation? >> >> WHOA! Now if that isn't a Gedankensprung. Also, I'm still very far from >> your train of thought, apparently: Now, the thing that code generators >> probably share is that they write code to files. It depends on what I'm >> trying to do of course, but I expect there's a good chance that if I >> wrote a code generator in Python, it wouldn't be particularly >> object-oriented at all. > > Well, I'm most experienced in OO, so writing OO in Python seems like > the way to start with Python. The visitor pattern uses single- > dispatch, that is, it determines which method to call be the type of > object passed in. I did some reading and it turned out that Python > can't do it without some tricks (function decorators and 3rd party > code). Well, yes: the name of a function or method refers to a single callable object and piece of code. if you care about the type of the argument, you must say so explicitly: class A: def dothing(self, obj): if isinstance(obj, str): self.dostringthing(obj) elif isinstance(obj, (int,float)): self.donumberthing(obj) else: self.dogenericthing(obj) # ... while python doesn't have C++-style function overloading, its alternative also doesn't have the limitations that come with it. -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
> > Yes, typo, I meant strictly. > Damn, I mean strongly. At least not for identifying which methods to call depending on the type/s. Karsten -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On 15 Jul., 20:28, Thomas Jollans wrote: > On 07/15/2010 07:58 PM, Karsten Wutzke wrote: > > > Hello, > > > this is obviously a Python OO question: > > > Since Python isn't stringly typed, > > I expect this is an innocent typo, and you mean strictly. > > > single-dispatch isn't available per se. So is the "double-dispatch" Visitor > > pattern, > Yes, typo, I meant strictly. > Wait, what? > First of all, python is strictly typed in that every object has exactly > one type, which is different from other types. So you can't do "1"+2, as > you can in some other languages. > > Anyway, this is interesting: Tell me more about how Python's dynamic > nature makes it impossible to do whatever you're trying to do. I'm > baffled. What are you trying to do, anyway? > > > which is usually used > > in OO systems to implement code generators. So, what is the de facto > > method in Python to handle source code generation? > > WHOA! Now if that isn't a Gedankensprung. Also, I'm still very far from > your train of thought, apparently: Now, the thing that code generators > probably share is that they write code to files. It depends on what I'm > trying to do of course, but I expect there's a good chance that if I > wrote a code generator in Python, it wouldn't be particularly > object-oriented at all. Well, I'm most experienced in OO, so writing OO in Python seems like the way to start with Python. The visitor pattern uses single- dispatch, that is, it determines which method to call be the type of object passed in. I did some reading and it turned out that Python can't do it without some tricks (function decorators and 3rd party code). For what I'm doing, I can't, or rather don't want to rely on 3rd party code (that has reasons). Thus, the visitor OO pattern must be replaced by some other way. As I expected, you already hinted a non-OO solution. Which is now that *I* am wondering what that would look like... Note, that I have an hierarchical object structure which I want to iterate over, so using OO looked natural to me. If there's a better approach, I'm all ears. Karsten -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
> Since Python isn't stringly typed, single-dispatch isn't available per > se. So is the "double-dispatch" Visitor pattern, which is usually used > in OO systems to implement code generators. So, what is the de facto > method in Python to handle source code generation? Do you mean strongly typed langauge? You are wrong, Python is a strongly typed language. Perhaps you are confusing strong/weak with dynamic/static? These attributes are orthogonal to each other. Python is a strongly and dynamicly typed language. The visitor pattern is required for double dispatching in *some* OO language like C++, to work around issues with inheritance and function overloading. Python's OO works differently. Christian -- http://mail.python.org/mailman/listinfo/python-list
Re: Code generator and visitor pattern
On 07/15/2010 07:58 PM, Karsten Wutzke wrote: > Hello, > > this is obviously a Python OO question: > > Since Python isn't stringly typed, I expect this is an innocent typo, and you mean strictly. > single-dispatch isn't available per se. So is the "double-dispatch" Visitor > pattern, Wait, what? First of all, python is strictly typed in that every object has exactly one type, which is different from other types. So you can't do "1"+2, as you can in some other languages. Anyway, this is interesting: Tell me more about how Python's dynamic nature makes it impossible to do whatever you're trying to do. I'm baffled. What are you trying to do, anyway? > which is usually used > in OO systems to implement code generators. So, what is the de facto > method in Python to handle source code generation? WHOA! Now if that isn't a Gedankensprung. Also, I'm still very far from your train of thought, apparently: Now, the thing that code generators probably share is that they write code to files. It depends on what I'm trying to do of course, but I expect there's a good chance that if I wrote a code generator in Python, it wouldn't be particularly object-oriented at all. -- http://mail.python.org/mailman/listinfo/python-list
Code generator and visitor pattern
Hello, this is obviously a Python OO question: Since Python isn't stringly typed, single-dispatch isn't available per se. So is the "double-dispatch" Visitor pattern, which is usually used in OO systems to implement code generators. So, what is the de facto method in Python to handle source code generation? Karsten -- http://mail.python.org/mailman/listinfo/python-list
Re: My extension code generator for C++
Rouslan Korneychuk, 03.07.2010 19:22:
The code also never uses PyArg_ParseTuple or its variants. It converts
every argument using the appropriate PyX_FromY functions. I noticed
PyBindGen does the following when a conversion is needed for one argument:
py_retval = Py_BuildValue((char *) "(O)", value);
if (!PyArg_ParseTuple(py_retval, (char *) "i", &self->obj->y)) {
Py_DECREF(py_retval);
return -1;
}
Py_DECREF(py_retval);
On the other hand, here's the implementation for __sequence__getitem__:
PyObject * obj_DVector___sequence__getitem__(obj_DVector
*self,Py_ssize_t index) {
try {
std::vector > &base =
cast_base_DVector(reinterpret_cast(self));
return PyFloat_FromDouble(base.at(py_ssize_t_to_ulong(index)));
} EXCEPT_HANDLERS(0)
}
Check the code that Cython uses for these things. It generates specialised
type conversion code that has received a lot of careful benchmarking and
testing on different platforms.
Stefan
--
http://mail.python.org/mailman/listinfo/python-list
Re: My extension code generator for C++
I missed one: func="operator[]" would also work, I assume? Yes, you can also supply a function if the first parameter accepts the type being wrapped (__rop__ methods will even accept the second parameter taking the wrapped type). -- http://mail.python.org/mailman/listinfo/python-list
Re: My extension code generator for C++
On 07/03/2010 01:54 PM, Thomas Jollans wrote: On 07/03/2010 07:22 PM, Rouslan Korneychuk wrote: It's still in the rough, but I wanted to give an update on my C++ extension generator. It's available at http://github.com/Rouslan/PyExpose Question that pops to mind immediately: How does this differentiate itself from SWIG? ( I can't say I'm familiar with SWIG, but the question had to be posed. ) I have never tried swig, but as far as I understand, SWIG uses a layered approach where part of the extension is defined C/C++ and that is wrapped in Python code. Mine implements the extension completely in C++. The documentation is a little slim right now but there is a comprehensive set of examples in test/test_kompile.py (replace the k with a c. For some reason, if I post this message with the correct name, it doesn't show up). The program takes an input file like module doc string class doc string func="operator[]" would also work, I assume? and generates the code for a Python extension. [snip] I'm really interested in what people think of this little project. How does it deal with pointers? What if something returns a const pointer - is const correctness enforced? When returning pointers or references, you either have to specify a conversion explicitly or use the "return-semantic" attribute. The current options are "copy", which dereferences the pointer and copies by value, and "managed-ref" which is for exposed classes, where the returned PyObject stores the value as a reference and holds on to a reference-counted pointer to the object the returned the value (there is also "self" which has nothing to do with returning pointers. With "self", the return value of the wrapped method is ignored and a pointer to the class is returned). I can easily add other options for "return-semantic", such as keeping a pointer and deleting it upon destruction. I just implemented the ones I need for the thing I'm working on. As far as returning const pointers and const correctness, I'm not sure exactly what you mean. If you mean is there a mechanism to hold on to const objects and prevent them form being modified, the answer is no. It's not something I need. All in all, it looks rather neat. Thomas Thanks for the comment. -- http://mail.python.org/mailman/listinfo/python-list
Re: My extension code generator for C++
On 07/03/2010 07:22 PM, Rouslan Korneychuk wrote: > It's still in the rough, but I wanted to give an update on my C++ > extension generator. It's available at http://github.com/Rouslan/PyExpose Question that pops to mind immediately: How does this differentiate itself from SWIG? ( I can't say I'm familiar with SWIG, but the question had to be posed. ) > > The documentation is a little slim right now but there is a > comprehensive set of examples in test/test_kompile.py (replace the k > with a c. For some reason, if I post this message with the correct name, > it doesn't show up). The program takes an input file like > > > > module doc string > > > class doc string > > > > > return-semantic="copy"/> func="operator[]" would also work, I assume? > > > > > and generates the code for a Python extension. > > [snip] > > I'm really interested in what people think of this little project. How does it deal with pointers? What if something returns a const pointer - is const correctness enforced? All in all, it looks rather neat. Thomas -- http://mail.python.org/mailman/listinfo/python-list
My extension code generator for C++
It's still in the rough, but I wanted to give an update on my C++
extension generator. It's available at http://github.com/Rouslan/PyExpose
The documentation is a little slim right now but there is a
comprehensive set of examples in test/test_kompile.py (replace the k
with a c. For some reason, if I post this message with the correct name,
it doesn't show up). The program takes an input file like
module doc string
class doc string
return-semantic="copy"/>
and generates the code for a Python extension.
The goal has been to generate code with zero overhead. In other words I
wanted to eliminate the tedium of creating an extension without
sacrificing anything. In addition to generating a code file, the
previous input would result in a header file with the following:
extern PyTypeObject obj_DVectorType;
inline PyTypeObject *get_obj_DVectorType() { return &obj_DVectorType; }
struct obj_DVector {
PyObject_HEAD
storage_mode mode;
std::vector > base;
PY_MEM_NEW_DELETE
obj_DVector() : base() {
PyObject_Init(reinterpret_cast(this),get_obj_DVectorType());
mode = CONTAINS;
}
obj_DVector(std::allocator const & _0) : base(_0) {
PyObject_Init(reinterpret_cast(this),get_obj_DVectorType());
mode = CONTAINS;
}
obj_DVector(long unsigned int _0,double const &
_1,std::allocator const & _2) : base(_0,_1,_2) {
PyObject_Init(reinterpret_cast(this),get_obj_DVectorType());
mode = CONTAINS;
}
obj_DVector(std::vector > const & _0)
: base(_0) {
PyObject_Init(reinterpret_cast(this),get_obj_DVectorType());
mode = CONTAINS;
}
};
so the object can be allocated in your own code as a single block of
memory rather than having a PyObject contain a pointer to the exposed type.
storage_type is an enumeration, adding very little to the size of the
Python object (or maybe nothing depending on alignment), but if you add
new-initializes="true" to the tag and the exposed type never
needs to be held by a pointer/reference (as is the case when the exposed
type is inside another class/struct), even that variable gets omitted.
The code also never uses PyArg_ParseTuple or its variants. It converts
every argument using the appropriate PyX_FromY functions. I noticed
PyBindGen does the following when a conversion is needed for one argument:
py_retval = Py_BuildValue((char *) "(O)", value);
if (!PyArg_ParseTuple(py_retval, (char *) "i", &self->obj->y)) {
Py_DECREF(py_retval);
return -1;
}
Py_DECREF(py_retval);
On the other hand, here's the implementation for __sequence__getitem__:
PyObject * obj_DVector___sequence__getitem__(obj_DVector
*self,Py_ssize_t index) {
try {
std::vector > &base =
cast_base_DVector(reinterpret_cast(self));
return PyFloat_FromDouble(base.at(py_ssize_t_to_ulong(index)));
} EXCEPT_HANDLERS(0)
}
(cast_base_DVector checks that base is initialized and gets a reference
to it with regard to how it's stored in obj_DVector. If the class is
new-initialized and only needs one means of storage, it's code will just
be "return obj_DVector->base;" and should be inlined by an optimizing
compiler.)
I'm really interested in what people think of this little project.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code Generator written in python
trzewiczek writes: > On 01/13/2010 05:09 PM, Arnaud Delobelle wrote: [...] >> Sure, here are some example of self-evaluating python objects, >> i.e. for each v below, >> >> v == eval(v) >> >> I'm quite proud of the last one. [...] >> v = "\"%s\" %% ((r\"%s\",)*2)" % ((r"\"%s\" %% ((r\"%s\",)*2)",)*2) >> >> :) >> >> > If you're proud of the last one, consider moving to Perl. Python is - > as I heard - about elegance and readability of code... No thanks. It's far too easy to write unreadable code in Perl and I like a challenge :) Seriously - this is a self-evaluating string, not code for landing a $1bn rocket on Mars. Do you expect it to be readable? I don't. However, I definitely find a certain elegance to it. -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
Re: Code Generator written in python
On 01/13/2010 05:09 PM, Arnaud Delobelle wrote:
nyoka writes:
Can someone help me with sample python code for a code generator
Sure, here are some example of self-evaluating python objects, i.e. for each v
below,
v == eval(v)
I'm quite proud of the last one.
v = (lambda x:x%('"''""'+x+'"''""'))("""(lambda
x:x%%('"''""'+x+'"''""'))(%s)""")
v = (lambda x:x%('r\"'+x+'\"'))(r"(lambda x:x%%('r\"'+x+'\"'))(%s)")
v = (lambda x:x%`x`)('(lambda x:x%%`x`)(%s)')
v = (lambda x: x+"("+`x`+")")('(lambda x: x+"("+`x`+")")')
v = "\"%s\" %% ((r\"%s\",)*2)" % ((r"\"%s\" %% ((r\"%s\",)*2)",)*2)
:)
If you're proud of the last one, consider moving to Perl. Python is - as
I heard - about elegance and readability of code...
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code Generator written in python
http://nedbatchelder.com/code/cog/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Code Generator written in python
En Wed, 13 Jan 2010 13:09:38 -0300, Arnaud Delobelle
escribió:
nyoka writes:
Can someone help me with sample python code for a code generator
Sure, here are some example of self-evaluating python objects, i.e. for
each v
below,
v == eval(v)
I'm quite proud of the last one.
And I'm still trying to disembowel it! :)
v = (lambda x:x%('"''""'+x+'"''""'))("""(lambda
x:x%%('"''""'+x+'"''""'))(%s)""")
v = (lambda x:x%('r\"'+x+'\"'))(r"(lambda x:x%%('r\"'+x+'\"'))(%s)")
v = (lambda x:x%`x`)('(lambda x:x%%`x`)(%s)')
v = (lambda x: x+"("+`x`+")")('(lambda x: x+"("+`x`+")")')
v = "\"%s\" %% ((r\"%s\",)*2)" % ((r"\"%s\" %% ((r\"%s\",)*2)",)*2)
--
Gabriel Genellina
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code Generator written in python
nyoka writes:
> Can someone help me with sample python code for a code generator
Sure, here are some example of self-evaluating python objects, i.e. for each v
below,
v == eval(v)
I'm quite proud of the last one.
v = (lambda x:x%('"''""'+x+'"''""'))("""(lambda
x:x%%('"''""'+x+'"''""'))(%s)""")
v = (lambda x:x%('r\"'+x+'\"'))(r"(lambda x:x%%('r\"'+x+'\"'))(%s)")
v = (lambda x:x%`x`)('(lambda x:x%%`x`)(%s)')
v = (lambda x: x+"("+`x`+")")('(lambda x: x+"("+`x`+")")')
v = "\"%s\" %% ((r\"%s\",)*2)" % ((r"\"%s\" %% ((r\"%s\",)*2)",)*2)
:)
--
Arnaud
--
http://mail.python.org/mailman/listinfo/python-list
Re: Code Generator written in python
nyoka wrote: > Can someone help me with sample python code for a code generator >>> print "print" print Seriously, you have to provide more information if you want a meaningful answer. If the generated code is Python, too, then the advice is most likely that you don't need to generate any code at all. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Code Generator written in python
nyoka, 13.01.2010 16:48: Can someone help me with sample python code for a code generator Such as Cheetah? http://www.cheetahtemplate.org/ BTW, you might want to be more specific about your problem at hand. Code generation is a rarely used technique in Python. Most of the time, it's more maintainable (and not necessarily harder or more work) to actually write the code by hand. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Code Generator written in python
Can someone help me with sample python code for a code generator -- http://mail.python.org/mailman/listinfo/python-list
Re: Integrating a code generator into IDLE
Sam Denton schrieb: Code generators seem to be popular in Python. (http://www.google.com/search?q=python+code-generator) Certainly not. The most of them will be used for generating bindings. Apart from that, you rareley (if ever) need to generate code. I have one that I'd like to integrate into IDLE. Ideally, I'd like to (1) have a new file type show up when I use the File/Open dialog, and (2) have a function key that lets me run my generator against the file, just like F5 lets me run my Python code; ideally, I'd like to re-purpose the F5 key to be file-type aware. I've got a simple extension written that uses the F6 key to "compile" my files, but two goals I've listed seem a bit beyond me. Does anyone have any advice/pointers? Or is one or both ideas impractical? Thanks! You might consider using eric, a python-ide written in python with the Qt-Framework. It allows plugins. Diez -- http://mail.python.org/mailman/listinfo/python-list
Re: Integrating a code generator into IDLE
On Sun, 01 Jun 2008 10:40:09 -0500, Sam Denton wrote: > Code generators seem to be popular in Python. I don't think so. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Integrating a code generator into IDLE
Code generators seem to be popular in Python. (http://www.google.com/search?q=python+code-generator) I have one that I'd like to integrate into IDLE. Ideally, I'd like to (1) have a new file type show up when I use the File/Open dialog, and (2) have a function key that lets me run my generator against the file, just like F5 lets me run my Python code; ideally, I'd like to re-purpose the F5 key to be file-type aware. I've got a simple extension written that uses the F6 key to "compile" my files, but two goals I've listed seem a bit beyond me. Does anyone have any advice/pointers? Or is one or both ideas impractical? Thanks! -- http://mail.python.org/mailman/listinfo/python-list
Re: C Source Code Generator For Test Cases
> You might want to look at COG (http://www.nedbatchelder.com/code/ > cog/). It might be helpful to you. I really enjoy using it and keep > finding things to use it with. Thanks Mike. I agree. COG looks really promising. -T -- http://mail.python.org/mailman/listinfo/python-list
Re: C Source Code Generator For Test Cases
On Sep 28, 1:48 pm, gamename <[EMAIL PROTECTED]> wrote: > Hi, > > Can anyone recommend a good method of using python to generate c > source code? I have tables of test cases to use as input to a > process which would generate the test's source code. The Cheetah tool > looks interesting. Has anyone used it? Any other suggestions? > > TIA, > -T You might want to look at COG (http://www.nedbatchelder.com/code/ cog/). It might be helpful to you. I really enjoy using it and keep finding things to use it with. Good luck. Mike -- http://mail.python.org/mailman/listinfo/python-list
Re: C Source Code Generator For Test Cases
> Instead of reading the testcase tables and generating source for test > routines you simply can do the tests right away. > Can't. :( This is for an embedded system. I need to create source (in C) on one machine and then compile on others. The only thing that I can be certain of is an ANSI compiler on any machine I use. -T -- http://mail.python.org/mailman/listinfo/python-list
Re: C Source Code Generator For Test Cases
On Fri, 28 Sep 2007 12:57:49 -0700, gamename wrote: >> How about using c-types to access your C-stuff to test, and use python + the >> testcase-tables to invoke that? >> > > Sure, that's possible. But the source code for tests (once all the > parms are read) > still needs to be generated. Calling the lib from python or from C, > there still > needs to be a way to generate 100+ test routines. ;-) Instead of reading the testcase tables and generating source for test routines you simply can do the tests right away. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: C Source Code Generator For Test Cases
> > How about using c-types to access your C-stuff to test, and use python + the > testcase-tables to invoke that? > Sure, that's possible. But the source code for tests (once all the parms are read) still needs to be generated. Calling the lib from python or from C, there still needs to be a way to generate 100+ test routines. ;-) -T -- http://mail.python.org/mailman/listinfo/python-list
Re: C Source Code Generator For Test Cases
gamename wrote: > Hi, > > Can anyone recommend a good method of using python to generate c > source code? I have tables of test cases to use as input to a > process which would generate the test's source code. The Cheetah tool > looks interesting. Has anyone used it? Any other suggestions? How about using c-types to access your C-stuff to test, and use python + the testcase-tables to invoke that? Diez -- http://mail.python.org/mailman/listinfo/python-list
C Source Code Generator For Test Cases
Hi, Can anyone recommend a good method of using python to generate c source code? I have tables of test cases to use as input to a process which would generate the test's source code. The Cheetah tool looks interesting. Has anyone used it? Any other suggestions? TIA, -T -- http://mail.python.org/mailman/listinfo/python-list
Re: I wrote a C++ code generator in Python, would anyone please help me to review the code? :)
I've added a document for fgen. Please check it. Thanks, Kevin [EMAIL PROTECTED] wrote: > Kevin Wan wrote: > > fgen is a free command line tool that facilitates cross platform c++ > > development, including header generation, cpp file generation, makefile > > generation, unit test framework generation, etc. > > > > http://sf.net/projects/fgen > > > > I'm not very familiar with Python. Any feedback are appreciated! > > No documentation? > > Am I supposed to reverse engineer all the source files to figure out > how I'm > supposed to use it? > > > Or > > anyone like to develop it with me? > > > > Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: I wrote a C++ code generator in Python, would anyone please help me to review the code? :)
Sorry, I didn't write that much document. But you can use fgen --help to get the usage. I'm writing document now. :) Thanks, Kevin [EMAIL PROTECTED] wrote: > Kevin Wan wrote: > > fgen is a free command line tool that facilitates cross platform c++ > > development, including header generation, cpp file generation, makefile > > generation, unit test framework generation, etc. > > > > http://sf.net/projects/fgen > > > > I'm not very familiar with Python. Any feedback are appreciated! > > No documentation? > > Am I supposed to reverse engineer all the source files to figure out > how I'm > supposed to use it? > > > Or > > anyone like to develop it with me? > > > > Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: I wrote a C++ code generator in Python, would anyone please help me to review the code? :)
I'm writing the document for fgen. You can use SVN to access the most updated files. Basically you can use fgen --help to get the usage. It's my c++ development tool, and I didn't spend that much time on writing document. Sorry. But I'm writing now. Thanks and waiting to work with you guys, Kevin Vineeth Kashyap wrote: > Hi, > I am interested in your proposal. I am basically a C/C++ programmer, > but recently fell in love with python. Please send more details on > fgen. We could probably start working. :) > Kevin Wan wrote: > > fgen is a free command line tool that facilitates cross platform c++ > > development, including header generation, cpp file generation, makefile > > generation, unit test framework generation, etc. > > > > http://sf.net/projects/fgen > > > > I'm not very familiar with Python. Any feedback are appreciated! Or > > anyone like to develop it with me? > > > > Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: I wrote a C++ code generator in Python, would anyone please help me to review the code? :)
Kevin Wan wrote: > fgen is a free command line tool that facilitates cross platform c++ > development, including header generation, cpp file generation, makefile > generation, unit test framework generation, etc. > > http://sf.net/projects/fgen > > I'm not very familiar with Python. Any feedback are appreciated! No documentation? Am I supposed to reverse engineer all the source files to figure out how I'm supposed to use it? > Or > anyone like to develop it with me? > > Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: I wrote a C++ code generator in Python, would anyone please help me to review the code? :)
Hi, I am interested in your proposal. I am basically a C/C++ programmer, but recently fell in love with python. Please send more details on fgen. We could probably start working. :) Kevin Wan wrote: > fgen is a free command line tool that facilitates cross platform c++ > development, including header generation, cpp file generation, makefile > generation, unit test framework generation, etc. > > http://sf.net/projects/fgen > > I'm not very familiar with Python. Any feedback are appreciated! Or > anyone like to develop it with me? > > Thanks. -- http://mail.python.org/mailman/listinfo/python-list
I wrote a C++ code generator in Python, would anyone please help me to review the code? :)
fgen is a free command line tool that facilitates cross platform c++ development, including header generation, cpp file generation, makefile generation, unit test framework generation, etc. http://sf.net/projects/fgen I'm not very familiar with Python. Any feedback are appreciated! Or anyone like to develop it with me? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Code generator
Hello NG! Can anybody explain me how to install the code generator fo ctypes on my pc? I use windows... for example I found this line command on the overview: python h2xml.py windows.h -o windows.xml -q -c Where do I have to type? and where do I have to put the file that I got from the repository? Thank you for the help! Massi -- http://mail.python.org/mailman/listinfo/python-list
Re: code Generator Help
Steve Holden wrote: > If this isn't spam I'll eat my hat. How many other irrelevant newsgroups > has this been sent to? Headers follow for abuse tracking and retribution. More precisely, the email is from a marketer in Pakistan. http://www.pid.org.pk/resume.html Note the lack of programming experience. The software mentioned comes from Alachisoft which is a subsidiary of Diyatech which does its software development in "South Asia". Andrew [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: code Generator Help
[EMAIL PROTECTED] wrote: Code Generators!!! I think now a days programmers should prefer Code Generator to do their coding rather than doing everything by hand. They are almost generator for every database. If you do n't have enough time write all the code by hand, invest some in code genetor and make you lifew easy. I just want to share my thought with this user group. You are welcome to send me an email about it [EMAIL PROTECTED] My favorite is TierDeveloper from www.alachisoft.com Here are some of features list on their website and I just copy paste it here. [feature list etc. snipped] If this isn't spam I'll eat my hat. How many other irrelevant newsgroups has this been sent to? Headers follow for abuse tracking and retribution. regards Steve Path: news1.east.cox.net!east.cox.net!filt02.cox.net!peer01.cox.net!cox.net!cyclone1.gnilink.net!gnilink.net!news.glorb.com!postnews.google.com!z14g2000cwz.googlegroups.com!not-for-mail From: [EMAIL PROTECTED] Newsgroups: comp.lang.python Subject: code Generator Help Date: 28 Dec 2004 07:56:18 -0800 Organization: http://groups.google.com Lines: 91 Message-ID: <[EMAIL PROTECTED]> NNTP-Posting-Host: 203.215.172.162 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1104249382 1818 127.0.0.1 (28 Dec 2004 15:56:22 GMT) X-Complaints-To: [EMAIL PROTECTED] NNTP-Posting-Date: Tue, 28 Dec 2004 15:56:22 + (UTC) User-Agent: G2/0.2 Complaints-To: [EMAIL PROTECTED] Injection-Info: z14g2000cwz.googlegroups.com; posting-host=203.215.172.162; posting-account=7YudzA0fMdqpJCBHcNyqldiXgatK Xref: cox.net comp.lang.python:394356 X-Received-Date: Tue, 28 Dec 2004 10:56:24 EST (news1.east.cox.net) -- Steve Holden http://www.holdenweb.com/ Python Web Programming http://pydish.holdenweb.com/ Holden Web LLC +1 703 861 4237 +1 800 494 3119 -- http://mail.python.org/mailman/listinfo/python-list
code Generator Help
Code Generators!!! I think now a days programmers should prefer Code Generator to do their coding rather than doing everything by hand. They are almost generator for every database. If you do n't have enough time write all the code by hand, invest some in code genetor and make you lifew easy. I just want to share my thought with this user group. You are welcome to send me an email about it [EMAIL PROTECTED] My favorite is TierDeveloper from www.alachisoft.com Here are some of features list on their website and I just copy paste it here. Cheers, Single & multi-table object mapping Unmapped objects (creates tables in db for them) Map objects to views as updateable Formula fields Identity, sequences, and trigger changed columns Static object queries 1-1, n-1, 1-n, and m-n relationships Stored procedure calls Bulk update and delete methods Custom load, insert, and update operations Datasets and Typed Datasets .NET components for COM+ .NET standalone components (for Windows Forms etc.) Export DDL scripts (New) Integrated SQL tool Database validation and synchronization Generate ASP.NET application Generate Windows Forms application Generate HTML design doc for objects C# and VB.NET support SQL Server 7.0/2000 (SQLClient) Microsoft Access (OLEDB) SQL Server 7.0/2000 (OLEDB) Oracle 8i/9i (OLEDB & OracleClient) DB2 7.x/8.1 (OLEDB) (New) Multiple databases in one project 100% VS.NET 2002/2003 integration Dynamic object queries Web services for objects Custom hooks (safe from code generation) Generate stored procedures for SQL Parent/Child relationship & life-cycle mgmt Generate Windows Forms remote client (New) Customize ASP.NET application GUI (New) Customize Windows Forms application GUI (New) Customize Windows Forms remote client GUI (New) -- http://mail.python.org/mailman/listinfo/python-list
