Some musings;
Beware, I edited title and original post to better reflect the point of the
thread.
\--
When I first installed Nim 0.13, I accepted that there will be "wtf-moments"
because I knew that it is work-in-progress. When press release of 1.0 will
eventually hit the fan, I surely hope
Hey I have another good one in the category "ignore the compiler and just go
back to the code".
import db_mysql, tables
type XchgSym = tuple[xchg: string, sym: string]
var xchg_symbol2id = initTable[XchgSym, int]()
# real code:
#let id =
Unfair quoting IMO, I said
> Or better yet, you ask a beginner who can read a tutorial again to look at
> some valid syntax. **I 'm not a fan of pathos.**
A friendlier tone would have produced a friendlier answer. But I'm changing
this to "just always be nice anyway", trying to listen to
I'm also a beginner and I'm also exasperated by error messages just like you.
Let's take C#, it's a language that was designed on purpose to be beginner
friendly, and the compiler outputs messages that are incredible and spot on.
This makes it frustration-free, and that's one key to adoption.
While doofenstein makes some good points especially about fragility with regard
to adding new fields and old data files, there is some real efficiency charm to
a "just memory map and go" pure binary native data approach. It's not always
fun to be parsing data files again and again. So, I would
Because it's very dangerous.
Simply having a compiler which puts structures in another layout or adding a
field to the object is enough to render all your previously generated files
useless.
If you just want to save and load data, I would rather serialise
Thanks for the compliments. You should probably learn about backward shift
deletion. It's a little tricky the first time you see it, but ultimately it's
better than tombstones and a bunch of ad hoc garbage collection rules. You can
look at `lib/pure/collections/tables.nim`. There are really
Probably there's no easy solution of this task
[Same for c++ on Stack
Overflow](https://stackoverflow.com/questions/3268801/how-do-you-de-serialize-a-derived-class-from-serialized-data)
[Comprehensive
guide](https://isocpp.org/wiki/faq/serialization#serialize-inherit-no-ptrs)
Thank you, it works. It strange that there is no possibility to make some cast
from string of seq[byte] directly to object
It would be too easy!
import streams, nesm
serializable:
type
TA = object of RootObj
TB = object of TA
f: int
var
a: ref TA
b: ref TB
new(b)
a = b
echo stringify(serialize(a))
@cblake omg such a concentration of goodness in this answer, thank you for the
tombstone warning. If I understand what you mean, I gave it some thought at the
time, and concluded it would be an idea to "garbage collect" if some metric
goes red, which is the solution google dense map appears to
Try [nesm](https://github.com/xomachine/NESM)
Have a look at this:
import streams
type
MyType* = object
somefield*: array[10, int16]
var t1, t2: MyType
t1.somefield[0] = 1
t2.somefield[0] = 2
var f = newFileStream("/tmp/tmp.mytype", fmWrite)
if not f.isNil:
f.write t1
We can create template with like this:
template withFile(name: string, body: untyped) =
let fh = open(name, ...)
defer: close(fh)
block:
body
But when template contain await, the compiler will complain the 'await' is
undeclared identifier. The
Sorry, it works correctly. But how to read it back? File contains several
instances of MyType, so I need to take subpart of file. I've tried this
let data = readFile("/tmp/tmp.mytype")
let ololo = cast[MyType](data[0 ..
Hello guys,
Is there any way to serialize object including its runtime type data? Both
[marshal](https://nim-lang.org/docs/marshal.html) and
[msgpack4nim](https://github.com/jangko/msgpack4nim#ref-types) don't support it
out-of-box.
import streams, msgpack4nim
type
I do
t.somefield[0] = 255
t.somefield[1] = 255
to check
I can do something like this:
type
MyType* = object
somefield*: array[10, int16]
var t: MyType
var f = newFileStream("/tmp/tmp.mytype", fmWrite)
if not fff.isNil:
f.write t
but result file contains garbage, size of file is 20 bytes.
So question
@lightness1024 - fair criticism of C++ STL.
modulo prime reduction of the hash code to a table address/array index is slow
because division is slow. In my tests using modulo can sometimes **triple** the
entire lookup time for simple integer keys due to the slowness of division! I
recommend you
I have a macro that creates a type and associated functions, and I'm calling
that from a template. I want to use identifier construction to append a suffix
to the template parameter, but the whole backticked AST (instead of the
constructed identifier) gets passed in to the macro. Is there some
@cblake - ok perfect. also naming things search-aware is important so I concur.
The python's OrderedDict: I didn't know that, it's a good thing nim is not
alone then. And in fact the presence of this is enough to not go and rename it.
(less disturbance)
In C++ the set/map is usually
@lightness1024 - good point. Another argument in favor of "KeyOrderedTable"
would be that it would probably show up in searches of the more generic
"OrderedTable". I don't think Nim has a key-ordered collection (EDIT - in the
stdlib) right now, but Araq has said he has a B-Tree waiting in the
Hey that makes sense though. Maybe adding a SortedTable will be enough to solve
this confusion. The mere presence of an OrderedTable and a SortedTable will
pick reader's curiosity and will naturally force us to look into why there are
two concepts that sounds similar.
you forgot to link libm, add option `-lm` at very end.
Hi
finelly is works!
I tried the way suggested Tetralux via make_standalone_toolchain.py and then
clang.
Simple echo works, but I tried simple pow from math and clang doesn't compile
it:
import math
var a = pow(5.09, 2.33)
clang -I
An OrderedTable is an ordered table. But it is not a _sorted_ table. IMO, but I
'm not a native speaker.
I just read in the module tables:
> OrderedTable is like Table but remembers insertion order
Well.. lol, thank you very much but that's not what we expect.
This is a "sequentially stable table", I suggest a rename to "SeqTable" maybe.
In C++ a set or a map are ordered tables. In C# there are
You are not alone.
Though in my case I wanted to remove copies when safe and it seemed like seq
wrapped in objects always triggered copies.
Anyway, relevant issues:
* Return by let/const values
[#6793](https://github.com/nim-lang/Nim/issues/6793)
* Distinguish let/var in assignment
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