Re: Use getenv with js
The error message could be better, of course, but JS has no `getEnv` and Nim's JS target is **not** NodeJS.
Re: New Fixed-Point Number Library
Thank you for your comments! Nice idea, I'll take a look at in.
Re: Can't install the bin tarball of nim 1.2.2.
Ups, sorry @araq! Totally forgot! You did mentioned this in your first reply. I'll try it.
Newbie question: why do I get a "No handles or timers registered in dispatcher" error?
I've simplified my issues down to a simple test case where I use spawn() to run
a proc that completes a future. It feels like it ought to be straightforward:
import asyncdispatch
import threadpool
let future = newFuture[string]()
let complete_future = proc (future_to_complete:Future[string]) =
future_to_complete.complete("woah")
spawn complete_future(future)
let str = waitFor future
echo str
Run
But on the waitFor line I get the following exception:
> Error: unhandled exception: No handles or timers registered in dispatcher.
> [ValueError]
I'm a total newbie so I'm sure I'm missing something key here. But what is it?
Use getenv with js
Hi everyone! when I try to compile this code into js (e.g. nim js main.nim)
import os
echo getEnv("USER")
Run
I'm getting the follow error:
.choosenim/toolchains/nim-1.2.2/lib/pure/includes/osenv.nim(97, 16) Error:
internal error: expr(nkBracketExpr, tyUncheckedArray)
Run
Was this supposed to work?
Re: More fuzz testing
printSeq is writing to stdout itself before returning a default value empty string.
Re: More fuzz testing
I would expect print first 1 3 5 7 printSeq(seq1 ,2) 1 3 Run
Re: "subsequence" type (like Go's "slice")
> There is also openArray. It's currently restricted to parameters due to > memory safety reasons, there is an RFC to extend it. I assume you mean [this](https://github.com/nim-lang/RFCs/issues/178)? What's the status of that and the other [Nim2020](https://github.com/nim-lang/RFCs/milestone/1) RFCs? It has always said 0% complete on that page, and 2020 is about half over. I don't believe any of it is 0% complete ;-)
Re: More fuzz testing
what's the bug?
Re: Norm 2.0.0
Interesting. Can you outline the learned lessons?
Re: "subsequence" type (like Go's "slice")
I'm writing code that manipulates portions of `seq``s, and I keep creating proc parameter lists that include ``input: openarray[byte]; inRange: var Slice[int]`, and then inside the proc I keep writing stuff like `input[inRange.a + i]` I have a large C++ codebase that uses a custom `slice` type that simply contains a pointer and a length, and I've found it extremely useful over the years; it really cleans up code that deals with byte ranges. (C++17's `string_view` is pretty much the same thing.) Of course it's very unsafe, but I'm used to that in C++. I'd like a safer version of it (more like Go's) in Nim. So I'm implementing one now; your toy sequence class from your ARC/ORC talk is proving very useful!
Re: Dual number type
Thank you, this solves the first problem I had. I don't understand though, why it can infer N from Dual[N, T] but not T. Anyways, the problem remains that scalar multiplication should work for arbitrarily nested duals, i.e. let a = dual[2, Dual[2, float]]( dual[2, float](1.0, [0.0, 0.0]), [dual[2, float](0.0, [0.0, 0.0]), dual[2, float](1.0, [0.0, 0.0])] ) Run but assuming the type T in Dual[N, T] can only be inferred if provided as another argument, I don't know what the function signature needs to be, so this fails: # Error: type mismatch: got echo 183.0*a Run The wanted output is the following just propagating the scalar multiplication through. An analogy I could think of would be viewing matrices as a vector of vectors where one can also propagate the scalar multiplication to the vectors. To be more clear: let want_expect = dual[2, Dual[2, float]]( dual[2, float](183.0, [0.0, 0.0]), [dual[2, float](0.0, [0.0, 0.0]), dual[2, float](183.0, [0.0, 0.0])] ) Run Thanks in advance, ~whiterock
Nim Days Chapter 21: Parser combinators and Nim
Here's a new chapter for one of my earliest code in nim nim-parsec [https://xmonader.github.io/nimdays/day21_parsec.html](https://xmonader.github.io/nimdays/day21_parsec.html)
More fuzz testing
Follows an edge case, an unexpected behaviour or a programmer's bug? let sp = ' ' let seq1 = @[1, 3, 5, 7] proc printSeq(s: seq, nprinted: int = -1) :string = var nprinted = if nprinted == -1: s.len else: min(nprinted, s.len) for i in 0 ..< nprinted: write(stdout, s[i], sp) write(stdout, "print first", printSeq(seq1), "\L") echo "printSeq(seq1, 2)", printSeq(seq1, 2) Run ouputs 1 3 5 7 print first 1 3 printSeq(seq1 ,2) Run
Norm 2.0.0
Hi all!
It is my great pleasure to announce Norm version 2.0.0
I've rewritten in from scratch, because the previous architecture turned out to
have unsolvable issues. There's zero backward compatibility, so if you've never
used Norm before, just start using the new version and don't bother looking and
previous versions, and if you do use Norm already, I'm afraid you'll have to
rewrite your code.
But this sacrifice is not in vain! Norm 2.0.0 is much more production ready. It
finally solves the n+1 problem, it lets you easily connect to as many DB
connections as you want, and you finally can have your models anywhere you
like. The behavior of DB procs is now more predictable, there are no more magic
object construction on the fly. The syntax is now more explicit.
To learn the new Norm, [visit the
docs](https://moigagoo.github.io/norm/norm.html).
And just to give you the taste of the new, Nim 1.2.0-driven API, here's how you
filter and update rows (taken from
[tsqlitesugar.nim](https://github.com/moigagoo/norm/blob/develop/tests/tsqlitesugar.nim#L40)):
discard @[newToy()].dup:
dbConn.select("price > ?", 50)
apply(doublePrice)
dbConn.update
Run
Re: New Fixed-Point Number Library
I think you could possibly make `fracbits` part of the type (that would mean you will have to use generics, everywhere). Like so: `type FixedPoint[fracBits: static[int]] = objectBut`. But `static` has many bugs yet so maybe it wouldn't work, just yet.
Re: New Fixed-Point Number Library
Really nice fixed point lib, with docs, tests and a way to generate different representation, operators... It is very complete, well done!
"subsequence" type (like Go's "slice")
As I get more fluent in Nim, the main tool I find myself missing is a lightweight reference to a range of bytes in memory — something that points to a portion of a `seq` without copying it. The closest equivalent I know of is Go's `slice[T]`, which is pretty ubiquitous — it's actually rare in Go to pass or return an array itself. I'm assuming this doesn't exist in Nim itself; I've spent some time scanning through the standard library docs, esp. the `system` and `sequtils` modules, and I think I'd have found it if it were there. But there might be a Nimble package. This could be implemented pretty simply, if non-optimally; something like type subseq*[T] = object parent: ref seq[T] range: Slice[Natural] Run The "non-optimal" part is the double-indirection getting to the bytes; it needs a `ref seq` to establish ownership so the GC will keep the heap block alive. One could add a direct pointer to the start of the range, in which case `range.a` isn't needed, so we get type subseq*[T] = object parent: ref seq[T] base: UncheckedArray[T] len: uint Run Both of these become unsafe if the seq is mutated; obviously if it's shortened enough to invalidate the end of the range, and more subtly the second design's `base` is invalidated if the seq has to grow its buffer. Not sure how to deal with that — it seems to require a Rust-like restriction that a sequence can't be mutated while any slices on it are extant, but I don't think Nim-as-we-know-it has ways to enforce that.
Re: Fuzz testing nim
Thanks saves me the report!
Re: Fuzz testing nim
Duplicate of [https://github.com/nim-lang/Nim/issues/13992](https://github.com/nim-lang/Nim/issues/13992) :)
Re: Fuzz testing nim
compiler crashes are not expected behavior. you should report it on github.
New Fixed-Point Number Library
Hi, After having had a lot of fun learning and testing Nim, I have started working on several libraries, including one on FPN (and another on CAD/GIS geometry). [https://gitlab.com/lbartoletti/fpn](https://gitlab.com/lbartoletti/fpn) A lot of the code comes from old notes that I had accumulated and coded in C, so the style may not be "NIMic" yet :)
Fuzz testing nim
var seq1: seq = @[1, 3, 5, 7] Run Error: internal error: genTypeInfo(tyNone) No stack traceback available To create a stacktrace, rerun compilation with ./koch temp c Run Is this an expected compiler behaviour?
Re: Custom HTML elements
Do you mean like web components? For SPAs have a look at Karax
Re: detectOs template in for loop
Second macro version outputs Ubuntu Run which is the correct answer!
Re: detectOs template in for loop
> But it's actually a tricky problem that might not be able to be solved with > an iteration of Distribution, which is probably why it's not in the stdlib. distros is for Nimble support, for nothing else. Detecting the distro is fundamentally flawed anyway, test for features, not for distros or versions.
Re: detectOs template in for loop
Thanks for the workaround. As an aside, it turns out for distro in Distribution: if detectOsImpl(distro): echo distro Run outputs two strings: Posix Linux Run The macro ouputs the first. What is the benefit of only accessing detectOsImpl through a template?
Re: Sending emails from Nim using SMTP
You can try to use my library: [https://github.com/enthus1ast/nimMime](https://github.com/enthus1ast/nimMime) it could be that you need to patch one or two things (pr welcome ;))
Re: detectOs template in for loop
Actually, the above won't work due to the general nature of Posix and Linux.
This may be better:
import macros
import distros
macro findOS*(): Distribution =
var body = newNimNode(nnkStmtList)
for distro in Distribution:
if distro in {Linux, Posix}:
continue
let distLit = ident($distro)
body.add(
quote do:
if detectOS(`distLit`):
return Distribution.`distLit`
)
# We want to check these last because they are more general
body.add(
quote do:
if detectOS(Linux):
return Distribution.Linux
if detectOS(Posix):
return Distribution.Posix
)
result = quote do:
(proc (): Distribution = `body`)()
echo findOS()
Run
But it's actually a tricky problem that might not be able to be solved with an
iteration of Distribution, which is probably why it's not in the stdlib.
Re: Termcurs
Update and harmonization for termkey.nim, for standard use of the source generator. designer progression big update for termcurs.nim
Re: detectOs template in for loop
This is, unfortunately, not possible at the moment with the way the template is written. You can work around this, however, with the following macro: import macros import distros macro findOS*(): Distribution = var body = newNimNode(nnkStmtList) # Mac is later in the enum than Posix, and # Mac is technically posix, so this is needed # to properly detect a Mac body.add( quote do: if detectOS(MacOSX): return Distribution.MacOSX ) for distro in Distribution: let distLit = ident($distro) body.add( quote do: if detectOS(`distLit`): return Distribution.`distLit` ) result = quote do: (proc (): Distribution = `body`)() echo findOS() Run
How to debug a library with gdb on windows?
So nim-gdb is working fine for me now with binaries. I can use it on VSCode aswell and it works great. finish.exe should set the NIM_GDB environment in the nim-gdb.bat if you let it setup mingw btw. I had to fix that manually. However, I've coded a simple library with nim which gets load some time after the main program is launched. The library itself is compiled with \--debugger:native --passL:-s --passL:-static-libgcc. I've expected that attaching gdb to the process should be enough to set breakpoints but thats not the case. So how to debug a library coded in nim? My try was: nim-gdb -p pid b main.nim:90 No symbol table is loaded. Use the "file" command. Make breakpoint pending on future shared library load? (y or [n]) y Breakpoint 1 (main.nim:83) pending. Library gets load now and breakpoint never gets hit and stay on pending all the time. Run
Re: Dual number type
Replace `x: SomeFloat;` with `x: T;` in your multiplication proc definition. The nim compiler can't determine which `T` you are wanting when there are no parameters with `T` as the type, so it's telling you that with `Maybe generic arguments are missing?`.
Re: Dual number type
If you want just scalar, you can change the definition of `T` in this case to: # scalar multiplication proc `*`*[N: static[int]; T: SomeFloat](x: T; y: Dual[N, T]): Dual[N, T] = result.real = x * y.real for i in 0..N-1: result.dual[i] = x * y.dual[i] # non-scalar multiplication proc `*`*[N: static[int]; T: Dual](x: T; y: Dual[N, T]): Dual[N, T] = # implementation here discard Run
Re: Passing a sequence by reference to a data type
Thanks, guys, I really appreciate your help, this community, and the welcoming nature of this forum.
Dual number type
I am trying to implement a dual number type in NIM, but struggling with with, for me, obscure error messages. Most likely I am missing something trivial, but after having poured in more than 2 hours in trying stuff and researching I still could not figure it out. Here's the minimum not working example: type Dual*[N: static[int], T: SomeFloat | Dual] = object real*: T dual*: array[N, T] proc dual*[N: static[int]; T: SomeFloat | Dual](real: T, dual: array[N, T]): Dual[N, T] = result.real = real result.dual = dual # scalar multiplication proc `*`*[N: static[int]; T: SomeFloat | Dual](x: SomeFloat; y: Dual[N, T]): Dual[N, T] = result.real = x * y.real for i in 0..N-1: result.dual[i] = x * y.dual[i] Run Testing this gives different errors which I put in the comments above the relevant lines of code. # Test #let a = dual[2, Dual[2, float]]( # dual[2, float](1.0, [0.0, 0.0]), # [dual[2, float](0.0, [0.0, 0.0]), dual[2, float](1.0, [0.0, 0.0])] #) let a = dual(3.0, [1.0, 0.0]) echo a # works as expected # Error: cannot instantiate 'Dual[N, T: float or float32 or float64 or Dual]' inside of type definition: '*'; Maybe generic arguments are missing? echo 183.0*a # Error: cannot instantiate: '*[2, float]' echo `*`[2, float](183.0, a) Run Thanks in advance, ~whiterock
Re: How to get & set text in clipboard ?
You could have a look at the WinAPI clipboard implementation of NiGui: [https://github.com/trustable-code/NiGui/blob/master/src/nigui/private/windows/platform_impl.nim#L421](https://github.com/trustable-code/NiGui/blob/master/src/nigui/private/windows/platform_impl.nim#L421)
Re: First take: parameters
Thanks, also another solution from the tutorial [advanced-types-varargs](https://nim-lang.org/docs/tut1.html#advanced-types-varargs) proc lfecho(data: varargs[string ,`$`]) = write(stdout, "\L") for s in items(data): write(stdout, s) Run
Re: Idea: Nim Online Conference
Once again a big "Thanks you" to every speaker, the quality of the talks were high throughout and the fact that every speaker was online during the stream and replied to questions made it even more enjoyable. Coming soon: A hackathon? How to organize one?
Sending emails from Nim using SMTP
Hallo, I would like to send emails from Nim using module smtp. However, I need to include an attachment with the message. Is it possible? If so, can you pls provide a code snippet to help me out?
detectOs template in for loop
What's the best solution for the following: import distros for distro in Distribution: if detectOs(distro): echo distro Run Error: undeclared field: 'distro' found 'distro' of kind 'forVar' Module distros source shows a Distribution.d enum is expected: template detectOs*(d: untyped): bool = ## Distro/OS detection. For convenience the ## required ``Distribution.`` qualifier is added to the ## enum value. detectOsImpl(Distribution.d) Run Exporting detectOsImpl would allow: for distro in Distribution: if detectOsImpl(distro): echo distro Run Any suggestions?
Re: Idea: Nim Online Conference
We shouldn't forget about @miran's awesome work here. Big thanks to him for all his work on scheduling, planning and organising this conference. It went incredibly smoothly, the bar has been set very high for the next conf :D
Custom HTML elements
Is it possible to create custom html elements with Nim?
Re: Can't install the bin tarball of nim 1.2.2.
You can use `-d:nimEmulateOverflowChecks` for 1.2.0
Re: Can't install the bin tarball of nim 1.2.2.
Thanks @shashlick. Yep. The GH issue looks like the same problem. So, this means I cannot install 1.2.2 from the normal tar ball, right? Therefore I'm back to square one: tar ball 1.2.0. installs, but gives me a compile error in the subsequent C compiler chain.
