Re: Anti-OOP... stupid?
On Tuesday, 14 February 2012 at 22:45:28 UTC, H. S. Teoh wrote:
On Tue, Feb 14, 2012 at 11:00:43PM +0100, Zero wrote:
Hello!
I've recently started to work with D, and I'll start a bigger
project soon, using it. For a few days I've been thinking
about the
approach I'll take here, and since I don't /have/ to use full
OOP in
D, I was wondering... how crazy is it to not use full OP
nowadays?
I do that all the time. I guess that makes me crazy. :)
[...]
What I want to know from you people... is that stupid? To even
think
about doing something like this? Basically mixing procedural
and OOP?
D allows you to program in functional style, OOP, procedural
style, or
any combination of them. There is a reason D was designed this
way. :)
I know about the dangers, and disadvantages, but if those
don't scare
one away, would you consider it bad, if someone did this, on a
larger
project?
[...]
OOP has its own share of dangers and disadvantages. Which,
sadly, most
people don't talk about very much because they don't have the
guts to go
against the current cool trendy bandwagon that everyone's
jumping on.
Templates, for one thing, don't fit very well into the OO
paradigm (ever
tried a virtual template function?), even though you *can* use
it to
enhance an OO-based design. And D's templates are one of the
best things
about D, ever.
Of course, many aspects of OO does help with large projects, so
it's
usually a good idea to take advantage of that. But that doesn't
mean you
*have* to use OO, or that it's bad to mix in procedural stuff
when it
suits you.
I mean, if you take OO to the extreme, that would require
excluding all
those evil procedural constructs like if statements and for
loops, and
write everything in terms of invoking object methods... like
this
monstrosity:
class MyClass {
void myMethod() {
IntVariable i;
ForLoopFactory.create(
new IntSetter(i.address(), new Number(0)),
new BooleanCondition(
new LessThanComparator(i.address(),
100)),
new IntAdder(i, 1),
new IfStatement(
new EqualComparator(i.address(),
new Number(42)),
new FunctionCaller(writeln.address(),
new String(Found it!)),
)
).execute();
}
}
which is, of course, completely ridiculous.
The bottom line is, use whatever tools work best for what you
need to
do. If OO works well, use it. If procedural code works well,
that use
it. If both works well in different cases, then use a mix of
both
depending on the circumstances.
Trying to shoehorn everything into an object is stupid.
T
I agree with the general sentiment to have a large toolbox and
using the right tool for the job be it functional, OOP, etc..
having said that, I have to strongly disagree with both claims
above.
1. D templates are an enhanced version of C++ templates which are
a poor design. The problem stems IMO not from issues with OOP but
rather with the horrible idea of C++-like templates. Other
languages have *much* better solutions which integrate better.
2. The above horrible example completely misrepresents OOP. The
correct way to truly do control flow in OOP is a-la smalltalk:
class My class {
void myMethod() {
...
100.times({ ... }); // for-loop
(myVar 42).ifTrue({ ... }); // if statement
(myVar 100).if({.. code if true ...}, {... code if false
...}); // if statement with else clause
...
}
}
etc.. incidentally, Smalltalk uses selectors (Objective-C is
basically fugly smalltalk..) : (expression) ifTrue: [ ^42 ]
ifFalse: [ ^24 ] the above returns 42 if true and 24 otherwise.
Re: Anti-OOP... stupid?
Many reasons why non-OOP methodology creates problems come from how scoping works in a language. In C, there's one global name-space, so declaring functions anywhere can lead to major problems: unexpected dependencies, unclear sequence of execution, aberrant mutations, name-space conflicts, etc. However in D, much like Python, true modules are supported by the language. There is no global scope the programmer has access to, only the module scope which matches file scope. This solves the name-space problem. Other than that, make sure your module level functions and values only depend on other modules in a predictable fashion, do only a small set of mostly self-contained things, and are well documented. Also remember that module-level variables have thread scope, so by default, each thread will have its own copy. - Vijay On Tue, 14 Feb 2012, Zero wrote: Hello! I've recently started to work with D, and I'll start a bigger project soon, using it. For a few days I've been thinking about the approach I'll take here, and since I don't /have/ to use full OOP in D, I was wondering... how crazy is it to not use full OP nowadays? Naturally one would use objects, but since this isn't C#, or Java, not freaking everything has to be an object. The C style kinda feels more natural to me. (I know, I know, C naturally can do some OOP like stuff, etc... but you get the idea, mainly normal functions, some globals, yada, yada.) What I want to know from you people... is that stupid? To even think about doing something like this? Basically mixing procedural and OOP? I know about the dangers, and disadvantages, but if those don't scare one away, would you consider it bad, if someone did this, on a larger project? I'm looking forward to your answers. Zero
Re: Anti-OOP... stupid?
On 02/15/2012 03:30 PM, foobar wrote: ... 1. D templates are an enhanced version of C++ templates which are a poor design. The problem stems IMO not from issues with OOP but rather with the horrible idea of C++-like templates. Other languages have *much* better solutions which integrate better. [snip.] Please elaborate. What kind of construct in a language that supports OO solves the same set of problems D templates do and is unequivocally a better design?
Re: Anti-OOP... stupid?
foobar: 1. D templates are an enhanced version of C++ templates which are a poor design. The problem stems IMO not from issues with OOP but rather with the horrible idea of C++-like templates. Other languages have *much* better solutions which integrate better. C++ is one of the most commonly used languages, probably there are billions of lines of C++ in use, and C++ library code uses templates often, so despite the well known flaws of C++ templates (bloat, bad error messages, etc), they are somehow good enough, they aren't horrible. Compared to C++, D templates introduce constraints, a better syntax, and more uniform/sane semantics of details. Bjarne Stroustrup is still trying to invent simplified Concepts to improve C++ templates, to give them static types. Java generics, C# generics, Ada generic programming, C++ templates, ML polymorphism, Haskell type inference with type classes, Haskell template extensions, are designed to satisfy different needs and constraints. All of them are used and useful, none of them are perfect. Bye, bearophile
Re: Anti-OOP... stupid?
On Wednesday, 15 February 2012 at 15:35:37 UTC, bearophile wrote: foobar: 1. D templates are an enhanced version of C++ templates which are a poor design. The problem stems IMO not from issues with OOP but rather with the horrible idea of C++-like templates. Other languages have *much* better solutions which integrate better. C++ is one of the most commonly used languages, probably there are billions of lines of C++ in use, and C++ library code uses templates often, so despite the well known flaws of C++ templates (bloat, bad error messages, etc), they are somehow good enough, they aren't horrible. Compared to C++, D templates introduce constraints, a better syntax, and more uniform/sane semantics of details. Bjarne Stroustrup is still trying to invent simplified Concepts to improve C++ templates, to give them static types. Java generics, C# generics, Ada generic programming, C++ templates, ML polymorphism, Haskell type inference with type classes, Haskell template extensions, are designed to satisfy different needs and constraints. All of them are used and useful, none of them are perfect. Bye, bearophile I beg to differ. I was talking about the *design* aspect of templates and you seem to agree that it is flawed. the design *is* horrible and can be compared to other better designs. The fact that it is used in so much software is a completely orthogonal matter. Most people use qwerty keyboards (including me) but that does not mean it's the superior design. on the contrary, it was *intentionally* designed to be flawed for historical reasons that are no longer relevant. what is good enough? it is highly subjective. Is it enough to be commonly used by many people? what other criteria would be required to classify as good enough and not worth improvement? should we never strive to achieve better designs? I don't know Haskell and won't comment on the above mentioned features but regarding generics (e.g in C#) - they have no conflicts with OOP and are a good feature.
Re: Anti-OOP... stupid?
On Wednesday, 15 February 2012 at 15:35:53 UTC, Timon Gehr wrote: On 02/15/2012 03:30 PM, foobar wrote: ... 1. D templates are an enhanced version of C++ templates which are a poor design. The problem stems IMO not from issues with OOP but rather with the horrible idea of C++-like templates. Other languages have *much* better solutions which integrate better. [snip.] Please elaborate. What kind of construct in a language that supports OO solves the same set of problems D templates do and is unequivocally a better design? Lisp/scheme macros come to mind :) There are no issues AFAIK integrating those with OOP, in fact the OOP features are implemented with macros (CLOS).
Re: Anti-OOP... stupid?
On 02/15/2012 09:17 PM, foobar wrote: On Wednesday, 15 February 2012 at 15:35:53 UTC, Timon Gehr wrote: On 02/15/2012 03:30 PM, foobar wrote: ... 1. D templates are an enhanced version of C++ templates which are a poor design. The problem stems IMO not from issues with OOP but rather with the horrible idea of C++-like templates. Other languages have *much* better solutions which integrate better. [snip.] Please elaborate. What kind of construct in a language that supports OO solves the same set of problems D templates do and is unequivocally a better design? Lisp/scheme macros come to mind :) =D. I actually thought about explicitly excluding those to get a more meaningful answer. Using runtime code modification is cheating. There are certainly ways to dynamically dispatch, expand and execute a macro in lisp. If every D program was allowed to include a complete D compiler, virtual template functions would work too. Can you point me to an implementation in lisp that does this and is actually fast enough to be considered for real work? There are no issues AFAIK integrating those with OOP, in fact the OOP features are implemented with macros (CLOS). You can use templates to implement a multiple-dispatch virtual function system just fine. We are not talking about implementing OOP using templates, but about using templated virtual methods. Anyway, I don't see your point yet: You seem to think templates are poorly designed because dynamic languages such as lisp are more flexible than static languages such as D?
Re: Anti-OOP... stupid?
On Wednesday, 15 February 2012 at 20:55:47 UTC, Timon Gehr wrote: snip Lisp/scheme macros come to mind :) =D. I actually thought about explicitly excluding those to get a more meaningful answer. Using runtime code modification is cheating. There are certainly ways to dynamically dispatch, expand and execute a macro in lisp. If every D program was allowed to include a complete D compiler, virtual template functions would work too. Can you point me to an implementation in lisp that does this and is actually fast enough to be considered for real work? There are no issues AFAIK integrating those with OOP, in fact the OOP features are implemented with macros (CLOS). You can use templates to implement a multiple-dispatch virtual function system just fine. We are not talking about implementing OOP using templates, but about using templated virtual methods. Anyway, I don't see your point yet: You seem to think templates are poorly designed because dynamic languages such as lisp are more flexible than static languages such as D? I'm no lisp expert and as such Google would be better than me to point to specific implementations and such :) regarding run-time modification of code - as I said, i'm no lisp expert but I did hear about lisp AOT compilers so it should be a matter of implementation. Another example which I'm more familiar with is Nemerle macros which are closely related to Lisp macros and follow similar design principles. In fact Nemerle macros are separately compiled plugins for the compiler which can manipulate the AST directly. Regarding templated virtual methods - take a look at: http://nemerle.org/wiki/index.php?title=Design_patterns
Re: Anti-OOP... stupid?
IMO, what would be stupid is that everything has to be object oriented. You have problems where OOP is good, and other where it isn't. Use the tool that fit what you want to accomplish. Screwdriver are great, but are useless when you are dealing with a nail. On Tuesday, 14 February 2012 at 22:00:44 UTC, Zero wrote: Hello! I've recently started to work with D, and I'll start a bigger project soon, using it. For a few days I've been thinking about the approach I'll take here, and since I don't /have/ to use full OOP in D, I was wondering... how crazy is it to not use full OP nowadays? Naturally one would use objects, but since this isn't C#, or Java, not freaking everything has to be an object. The C style kinda feels more natural to me. (I know, I know, C naturally can do some OOP like stuff, etc... but you get the idea, mainly normal functions, some globals, yada, yada.) What I want to know from you people... is that stupid? To even think about doing something like this? Basically mixing procedural and OOP? I know about the dangers, and disadvantages, but if those don't scare one away, would you consider it bad, if someone did this, on a larger project? I'm looking forward to your answers. Zero
Re: Anti-OOP... stupid?
On Tue, Feb 14, 2012 at 11:00:43PM +0100, Zero wrote:
Hello!
I've recently started to work with D, and I'll start a bigger
project soon, using it. For a few days I've been thinking about the
approach I'll take here, and since I don't /have/ to use full OOP in
D, I was wondering... how crazy is it to not use full OP nowadays?
I do that all the time. I guess that makes me crazy. :)
[...]
What I want to know from you people... is that stupid? To even think
about doing something like this? Basically mixing procedural and OOP?
D allows you to program in functional style, OOP, procedural style, or
any combination of them. There is a reason D was designed this way. :)
I know about the dangers, and disadvantages, but if those don't scare
one away, would you consider it bad, if someone did this, on a larger
project?
[...]
OOP has its own share of dangers and disadvantages. Which, sadly, most
people don't talk about very much because they don't have the guts to go
against the current cool trendy bandwagon that everyone's jumping on.
Templates, for one thing, don't fit very well into the OO paradigm (ever
tried a virtual template function?), even though you *can* use it to
enhance an OO-based design. And D's templates are one of the best things
about D, ever.
Of course, many aspects of OO does help with large projects, so it's
usually a good idea to take advantage of that. But that doesn't mean you
*have* to use OO, or that it's bad to mix in procedural stuff when it
suits you.
I mean, if you take OO to the extreme, that would require excluding all
those evil procedural constructs like if statements and for loops, and
write everything in terms of invoking object methods... like this
monstrosity:
class MyClass {
void myMethod() {
IntVariable i;
ForLoopFactory.create(
new IntSetter(i.address(), new Number(0)),
new BooleanCondition(
new LessThanComparator(i.address(),
100)),
new IntAdder(i, 1),
new IfStatement(
new EqualComparator(i.address(),
new Number(42)),
new FunctionCaller(writeln.address(),
new String(Found it!)),
)
).execute();
}
}
which is, of course, completely ridiculous.
The bottom line is, use whatever tools work best for what you need to
do. If OO works well, use it. If procedural code works well, that use
it. If both works well in different cases, then use a mix of both
depending on the circumstances.
Trying to shoehorn everything into an object is stupid.
T
--
Государство делает вид, что платит нам зарплату, а мы делаем вид, что
работаем.
Re: Anti-OOP... stupid?
On 02/14/2012 11:06 PM, deadalnix wrote: IMO, what would be stupid is that everything has to be object oriented. You have problems where OOP is good, and other where it isn't. Use the tool that fit what you want to accomplish. Screwdriver are great, but are useless when you are dealing with a nail. Not exactly useless. Therefore it is hard to notice that they are not really fit for the job until having used a hammer. ;)
Re: Anti-OOP... stupid?
On 02/14/2012 11:00 PM, Zero wrote:
Hello!
I've recently started to work with D, and I'll start a bigger project
soon, using it. For a few days I've been thinking about the approach
I'll take here, and since I don't /have/ to use full OOP in D, I was
wondering... how crazy is it to not use full OP nowadays?
Naturally one would use objects, but since this isn't C#, or Java, not
freaking everything has to be an object. The C style kinda feels more
natural to me. (I know, I know, C naturally can do some OOP like stuff,
etc... but you get the idea, mainly normal functions, some globals,
yada, yada.)
What I want to know from you people... is that stupid? To even think
about doing something like this? Basically mixing procedural and OOP? I
know about the dangers, and disadvantages, but if those don't scare one
away, would you consider it bad, if someone did this, on a larger project?
I'm looking forward to your answers.
Zero
I think that is not stupid at all.
Approaching the problem the way that feels most natural is likely a good
idea. As long as you actively keep in mind code quality measures such as
extensibility and maintainability, everything should work out nicely. I
encourage you to use the right abstractions. If something should be a
free-standing function, use a free-standing function. If it is hard to
force the involved objects into a hierarchy, use templates instead of/in
combination with sub-typing and inheritance. If you want to parameterize
a function on a few actions, consider using closures. If it is really
clear how a well-designed class hierarchy would look like, use OOP. etc.
The basic achievement of OOP is that it can be used to replace
procedural code of this general form:
void foo(ref S x){
switch(x.kind){
case KIND1:
...
break;
case KIND2:
...
break;
...
}
}
void bar(ref S x){
switch(x.kind){
case KIND1:
...
break;
...
}
}
This pattern emerges very often in practise, that is why OOP is useful.
If you have anything that should work like that, using classes will do
the job. Whether or not you apply OOP, make sure to keep stuff
extensible. It does not hurt at all if your code base is more flexible
than necessary.
Re: Anti-OOP... stupid?
On Tue, Feb 14, 2012 at 11:47:52PM +0100, Timon Gehr wrote: [...] It does not hurt at all if your code base is more flexible than necessary. [...] This needs to be taken in moderation, though. I've had to work with code that was unnecessarily flexible. (I.e., over-engineered.) So flexible, in fact, that almost none of us knew how to use it, and the code ended up deteriorating into a morass of hacks attempting to bypass an overly-general framework that nobody understood. One particularly bad example was that part of the system had a whole hierarchy of database-access classes, intended to replace having to write SQL directly. The problem was that it was so poorly documented, and so difficult to understand, not to mention requiring a instantiating a whole bunch of objects just to do something as simple as SELECT * FROM some_table;, that eventually people just resorted to writing a function for executing SQL directly, thus bypassing the entire over-engineered mess. And that was only a small part of it. There were other beautifully designed, fully OO, and fully generic classes, that accomplished everything from the most trivial of tasks to the most advanced high-level abstractions. Like the IPC mechanism, for which at one point I had to write code to get through *six* layers of abstraction just to call a single function. One layer of which involved fwrite(), fork(), exec(), and fread(). Such was the result of the original code base being much too flexible than it needed to be. T -- Why are you blatanly misspelling blatant? -- Branden Robinson
Re: Anti-OOP... stupid?
On 15 February 2012 12:12, H. S. Teoh hst...@quickfur.ath.cx wrote: On Tue, Feb 14, 2012 at 11:47:52PM +0100, Timon Gehr wrote: [...] It does not hurt at all if your code base is more flexible than necessary. [...] This needs to be taken in moderation, though. I've had to work with code that was unnecessarily flexible. (I.e., over-engineered.) So flexible, in fact, that almost none of us knew how to use it, and the code ended up deteriorating into a morass of hacks attempting to bypass an overly-general framework that nobody understood. One particularly bad example was that part of the system had a whole hierarchy of database-access classes, intended to replace having to write SQL directly. The problem was that it was so poorly documented, and so difficult to understand, not to mention requiring a instantiating a whole bunch of objects just to do something as simple as SELECT * FROM some_table;, that eventually people just resorted to writing a function for executing SQL directly, thus bypassing the entire over-engineered mess. And that was only a small part of it. There were other beautifully designed, fully OO, and fully generic classes, that accomplished everything from the most trivial of tasks to the most advanced high-level abstractions. Like the IPC mechanism, for which at one point I had to write code to get through *six* layers of abstraction just to call a single function. One layer of which involved fwrite(), fork(), exec(), and fread(). Such was the result of the original code base being much too flexible than it needed to be. T -- Why are you blatanly misspelling blatant? -- Branden Robinson Basically, flexibility is good, but you have to make sure you are actually writing a program, not a platform or framework, or worse a COBOL. (COBOL being COmmon Business-Oriented Language, intended for business people to use, and let programmers get back to writing device drivers .)
Re: Anti-OOP... stupid?
On 02/15/2012 12:12 AM, H. S. Teoh wrote: On Tue, Feb 14, 2012 at 11:47:52PM +0100, Timon Gehr wrote: [...] It does not hurt at all if your code base is more flexible than necessary. [...] This needs to be taken in moderation, though. I've had to work with code that was unnecessarily flexible. (I.e., over-engineered.) So flexible, in fact, that almost none of us knew how to use it, and the code ended up deteriorating into a morass of hacks attempting to bypass an overly-general framework that nobody understood. One particularly bad example was that part of the system had a whole hierarchy of database-access classes, intended to replace having to write SQL directly. The problem was that it was so poorly documented, and so difficult to understand, not to mention requiring a instantiating a whole bunch of objects just to do something as simple as SELECT * FROM some_table;, that eventually people just resorted to writing a function for executing SQL directly, thus bypassing the entire over-engineered mess. Directly executing SQL is a much more flexible approach ;). And that was only a small part of it. There were other beautifully designed, fully OO, and fully generic classes, that accomplished everything from the most trivial of tasks to the most advanced high-level abstractions. Like the IPC mechanism, for which at one point I had to write code to get through *six* layers of abstraction just to call a single function. One layer of which involved fwrite(), fork(), exec(), and fread(). Such was the result of the original code base being much too flexible than it needed to be. T For what I am concerned, flexible means *simple* to adapt, not that the existing code is so bloated and general that it does not need to be changed in order to implement a new functionality. In fact, I'd argue that such a design is inflexible: All new code is assumed to follow the bounds of the legacy code base.
Re: Anti-OOP... stupid?
H. S. Teoh:
I mean, if you take OO to the extreme, that would require excluding all
those evil procedural constructs like if statements and for loops, and
write everything in terms of invoking object methods... like this
monstrosity:
class MyClass {
void myMethod() {
IntVariable i;
ForLoopFactory.create(
new IntSetter(i.address(), new Number(0)),
new BooleanCondition(
new LessThanComparator(i.address(),
100)),
new IntAdder(i, 1),
new IfStatement(
new EqualComparator(i.address(),
new Number(42)),
new FunctionCaller(writeln.address(),
new String(Found it!)),
)
).execute();
}
}
which is, of course, completely ridiculous.
Smalltalk is a language composed of a very small number of parts, where every
thing is an object. So in a sense, you write code like that, with a better
syntax.
Bye,
bearophile
Re: Anti-OOP... stupid?
On Tue, Feb 14, 2012 at 06:42:02PM -0500, bearophile wrote:
H. S. Teoh:
I mean, if you take OO to the extreme, that would require excluding all
those evil procedural constructs like if statements and for loops, and
write everything in terms of invoking object methods... like this
monstrosity:
class MyClass {
void myMethod() {
IntVariable i;
ForLoopFactory.create(
new IntSetter(i.address(), new Number(0)),
new BooleanCondition(
new LessThanComparator(i.address(),
100)),
new IntAdder(i, 1),
new IfStatement(
new EqualComparator(i.address(),
new Number(42)),
new FunctionCaller(writeln.address(),
new String(Found it!)),
)
).execute();
}
}
which is, of course, completely ridiculous.
Smalltalk is a language composed of a very small number of parts,
where every thing is an object. So in a sense, you write code like
that, with a better syntax.
[...]
True, but that doesn't mean that it's evil to not program in Smalltalk.
:-)
T
--
Don't modify spaghetti code unless you can eat the consequences.
