Re: Generics instantiate problems
What I can understand that you need the lib's user should implement their own proc implementation right? Actually tables modules exactly does like that, when the user wants to use a specific object as the key, should implement `hash` and `==` so the object can be used as key. It's also catch-able during compile-time.
Re: getFileSize async and sync
It's different because `AsyncFile` keeps its `fd` field private. The Windows one is using the version from `winlean` which actually wrapper for `GetFileSize` from win32. Also, windows has peculiarity of different handling whether the file handle is synchronous and asynchronous one. That's why it's using the wrapper.
Re: Control mouse in Windows
Most viable option is using [winim](https://github.com/khchen/winim/) and just searching on internet how to work with Win32 API. Another way is using available example in rosetta code [simulating keyboard](https://rosettacode.org/wiki/Simulate_input/Keyboard#Nim) and add/change some codes to type MouseEvent = enum meMove = 0x0001 meLeftDown = 0x0002 meLeftUp = 0x0004 meAbsolute = 0x8000 proc initMouse: Input = result.`type` = clong itMouse var mouse = MouseInput(mouseData: 0, dx: 0, dy: 0, dwFlags: meAbsolute.culong or meMove.culong) result.hwin = InputUnion(mi: mouse) proc main = var mouse = initMouse() # set mouse xy pixel position mouse.hwin.mi.dx = clong 35_000 mouse.hwin.mi.dy = clong 35_000 # move it to intended position sendInput(1, addr mouse, sizeof(mouse).cint) sleep 1000 # flag to press the left mouse button mouse.hwin.mi.dwFlags = meAbsolute.culong or meLeftDown.culong or meLeftUp.culong # actually pressing the left mouse button sendInput(1, addr mouse, sizeof(mouse).cint) main() Run
Re: How Seq work with objects ?
> By removing something from the seq it needs to be reordered. ( shift elements > ) If you don't need the ordering, use [del](https://nim-lang.org/docs/system.html#del%2Cseq%5BT%5D%5BT%5D%2CNatural) Try the testing by choosing the span element randomly instead of pre-determined value. It will ensure compiler couldn't optimize the entire loop-deleting. Or from value from program arguments. Also object (pretty much) possibly allocated on stack while ref allocated in heap. Stack allocation is always faster.
Re: examples or documentation of Source Code filters
I used it to generate Golang boilerplate source codes for my last job.
Re: FFI: how to avoid naming arguments in C functions
$ c2nim --header gr.h gr.h(27, 25) Error: token expected: ; Run AFAIK, c2nim cannot read something with c custom macro. You can edit the header temporarily to remove that custom macro. In this case it's the `DLLEXPORT`.
Re: Some rant about nim
just a genuine question > > Not null safe by default How compiler know whether the data is nil or not if the data for example taken from IO? Or is it adding the additional `if thedata == nil` in the code? But the checking still done in run-time right? Or is it just limited to data/object construction?
Re: Why whitespace?
> What other arguments do they have against using tab? I got this from a tweet, just food for thought: > Remember, when you are read, you do not know you are dead. It is only painful > for others. It's the same when you use tabs and not spaces ;D
Re: How to split stderr/stdout of a subprocess?
The streams implementation on Windows (FileHandleStream to be precise) didn't implement peekDataImpl, setPositionImpl and getPositionImpl hence it crashed because the streams module accessing nil implementation. I actually fixed this (not PR-ed it yet tho, maybe already fixed in devel too, haven't checked it yet), but the actual problem is another, it's the C buffer that wouldn't flush to stdout/stderr handle until the the subprocess' buffer is full.
Re: Looking for someone to continue Nimmongo!
[https://github.com/SSPkrolik/nimongo/pull/81](https://github.com/SSPkrolik/nimongo/pull/81) there, added for limited elementary functionalities for GridFS. Unfortunately I never intensively used mongo except for simplest CRUD and those GridFS features only tested on Windows, very likely you need to test for Linux and/or Bsd variants. My Mongodb version is 4.0.5
Re: How to split stderr/stdout of a subprocess?
perhaps like this
#include
int main() {
fprintf(stdout, "This is from hello to stdout\n");
fprintf(stderr, "This is from hello to stderr\n");
return 0;
}
Run
and our nim file
import os, osproc, selectors
when defined(windows):
import streams
proc main =
when defined(linux):
let prc = startProcess("./a.out", options = {})
let errh = errorHandle prc
let outh = outputHandle prc
var stor = newSelector[string]()
defer: stor.close()
stor.registerHandle(int errh, {Read}, "")
stor.registerHandle(int outh, {Read}, "")
var tempout, temperr: File
running = tempout.open(outh)
running = temperr.open(errh)
var running = true
while running:
let keys = stor.select -1
for k in keys:
if k.errorCode.int != 0:
echo k.errorCode.osErrorMsg()
running = false
continue
if k.fd == outh:
echo "stdout: ", tempout.readLine
elif k.fd == errh:
echo "stderr: ", temperr.readLine
close prc
else:
echo "on windows"
let prc = startProcess("./a.exe", options = {})
var errstream = errorStream prc
var outstream = outputStream prc
while true:
var data = errstream.readLine
if data == "":
break
else:
echo "stderr: ", data
data = outstream.readLine
if data == "":
break
else:
echo "stdout: ", data
main()
Run
Note that on windows, selectors doesn't work with file, trying to use
createIoCompletionPort apparently couldn't work because the pipe is busy,
because of this also we cannot use ReOpenFile to enable flag
FILE_FLAG_OVERLAPPED. But, we got stream there so we can emulate async with
peek proc variants (peekStr and peekLine). cmiiw
Re: How to upload large files efficiently and quickly with Jester?
> it seems there is a offset error in the code (files are not identically but > shifted by some bytes at certain offsets) This is quite tricky to find out, TBH. I tried running it on windows and debian (in virtual box) and using chromium and firefox (both on windows) and it gave the correct files. I hadn't tried with linux box yet though. > Will the websocket work if I use the nginx as a frontend with ssl? it's supposed to be working fine, nginx would handle the handshake and the apps would only receive the socket connection, I remembered there's some option to be set to enable websocket on nginx, but never actually tried it too tho.
Re: How to upload large files efficiently and quickly with Jester?
Uploading file has been tricky, but thankfully nowadays there's websocket to
send blob. Here's example how to send a file.
import os, jester, asyncdispatch, htmlgen, asyncfile, asyncstreams, streams
import strutils
import ws, ws/jester_extra
settings:
port = Port 3000
routes:
get "/":
var html = """
function submit_file() {
let ws = new WebSocket("ws://localhost:3000/ws-upload");
let filedom = document.querySelector("#input-field");
ws.onmessage = function(evnt) {
console.log(evnt.data);
}
ws.onopen = function(evnt) {
ws.send(filedom.files[0].name);
ws.send(filedom.files[0].slice());
ws.close();
}
return true;
}
"""
for file in walkFiles("*.*"):
html.add "" & file & ""
html.add ""
html.add ""
html.add ""
html.add ""
resp(html)
get "/ws-upload":
try:
var wsconn = await newWebSocket(request)
await wsconn.send("send the filename")
var fname = await wsconn.receiveStrPacket()
var f = openAsync(fname, fmWrite)
while wsconn.readyState == Open:
let (op, seqbyte) = await wsconn.receivePacket()
if op != Binary:
resp Http400, "invalid sent format"
wsconn.close()
return
var cnt = 0
if seqbyte.len < 4096:
await f.write seqbyte.join
continue
while cnt < (seqbyte.len-4096):
let datastr = seqbyte[cnt .. cnt+4095].join
cnt.inc 4096
await f.write(datastr)
wsconn.close()
f.close()
except:
echo "websocket close: ", getCurrentExceptionMsg()
resp Http200, "file uploaded"
Run
Re: How to upload large files efficiently and quickly with Jester?
It seems the problem is elsewhere, not on how writing it to file, whether
sync/async file write.
Idk what to tweak on Jester to support larger chunk processing. As for example
on writeFromStream (not actually solving the problem tho):
routes:
post "/upload":
var f: AsyncFile
var fstream = newFutureStream[string]("routes.upload")
try:
f = openAsync("uploaded.file", fmWrite)
except IOError:
echo getCurrentExceptionMsg()
resp Http500, "Cannot upload file"
return
defer: f.close
var datastream =
newStringStream(request.formData.getOrDefault("file").body)
var asyncwrite = f.writeFromStream(fstream)
while not datastream.atEnd:
# read each of 1 MB
let strdata = datastream.readStr(1024 * 1024)
await fstream.write strdata
fstream.complete
resp Http200, "uploaded"
Run
Re: Using Nim without garbage collection.
spammer? [https://forum.nim-lang.org/t/5791](https://forum.nim-lang.org/t/5791)
Re: How to upload large files efficiently and quickly with Jester?
try to use [writeFromStream](https://nim-lang.github.io/Nim/asyncfile.html#writeFromStream%2CAsyncFile%2CFutureStream%5Bstring%5D).
Re: Why does this proc have side effects?
rand proc has side effect.
Re: Naming conventions - need leading underscore
Having _ as initial variable name only acts as visual cue, it's not related to readability or anything. Having clear/distinct/helpful/noisy visual cues doesn't change the fact whether the code is well written or not. What actually helpful is good structure and sane APIs. Whatever the variable name it is.
Re: Check if a procedure exists for a given type at compile time
Same case [https://forum.nim-lang.org/t/5792#35941](https://forum.nim-lang.org/t/5792#35941)
Re: Is there a default initializer that can be overloaded?
> Error: overloaded 'initElement' leads to ambiguous calls You tried to overload using generic but actually proc overload usually done with argument types. When you defined generic, it's actually creating overload proc based on argument type, for example proc add[T: SomeInteger](a, b: T): T = a + b discard add(4'u32, 5'u32) discard add(4'i32, 5'i32) Run would actually have proc add(a, b: uint32): uint32 = a + b proc add(a, b: int32): int32 = a + b Run CMIIW
Re: I wrote some nim code that works, but I don't understand how/why it works.
> template/generic instantiation of + from here This means + is generic and the real operation/error is elsewhere. Error: type mismatch: got but expected one of: iterator items[T](a: seq[T]): T first type mismatch at position: 1 required type for a: seq[T] . Run Means something error happened to make the compiler couldn't expand to items iterator. You need to expand it by yourself to find out. proc addConstraints*[T, V](constraints: var Constraints[T, V], choice: T, consts: seq[V]) = for c in consts: constraints[choice].incl c Run This will lead to interesting error yet it's crucial that, constraints has no key of i:1 (of course, it the `choice` arg supplied). If you know the actual error, then you just modify your code to proc addConstraints*[T, V](constraints: var Constraints[T, V], choice: T, consts: seq[V]) = let hasKey = choice in constraints: for c in consts: if hasKey: constraints[choice].incl c else: constraints[choice] = @[c].toHashSet() Run That way you avoid the KeyError that thrown out.
Re: Is there a default initializer that can be overloaded?
> I have to provide an initElement proc in the generic module in order to > compile foo[T] (line #10). That's the reason there's a forward declaration of > initElement (line #7). I tried your code, removed the forward-declaration and fixed your initElement definition and it's working fine. proc initElement[T: TypeInstance]: T = result.c = 'E' discard foo[TypeInstance]() Run I tried with `compile` proc and tried to call with `discard foo[int]()` and the compiler throw out error with error message supplied to error pragma. Try it.
Re: Accessing selectors from dispatcher ? why?
[getIoHandler](https://nim-lang.github.io/Nim/asyncdispatch.html#getIoHandler%2CPDispatcher) will returning IOCP Handle on Windows or [Selector[AsyncData]](https://github.com/nim-lang/Nim/blob/devel/lib/pure/asyncdispatch.nim#L1137-L1138) on Unix
Re: Is there a default initializer that can be overloaded?
If I understand you correctly, you wanted the client/user of the module to
provide their own initElement proc of their type, didn't you?
In that case, you're able to ensure the compiler to check whether the user
provide their own initElement using
[compile](https://nim-lang.github.io/Nim/system.html#compiles%2Cuntyped) proc.
proc foo[T]: T =
when not compiles(initElement[T]()):
{.error: "please provide initElement proc for your type".}
result = initElement[T]()
Run
Re: Walking trees without recursive iterators
> If Nim has setjump/longjump features (I've just found them in segfaults > library!), I could change that pattern to write two coroutines, consumer and > producer. There's [coro](http://nim-lang.github.io/Nim/coro.html) module in case you didn't realize it. > Is there a standard way to resume an iterator in Nim? For instance, if I save > a closure iterator in a stack, after having started looping on it, is there a > way to resume the iteration? Perhaps, I misunderstood, but do you means iterator invocation? You can check whether the iterator has finished or not with [finished](https://nim-lang.github.io/Nim/system.html#finished%2CT) proc and just simply call like `myiterator()` would progress your iterator. You don't have to put an iterator in for-loop syntax just to iterate it.
Re: "Returning" a proc from a template
> /usercode/in.nim(25, 15) Error: type mismatch: got >From this message is quite clear that your template didn't return the untyped >as unchecked proc. >From your template definition, you just defined a proc that only available >within that template scope and you didn't return anything. Simply add a line >would imply you're returning something template cmpTaskField*(fieldName: untyped): untyped = proc cmpT(task1, task2: Task): int = cmp(task1.fieldName, task2.fieldName) cmpT Run
Re: Safe access operator - how could this be done?
This immediately leave the proc when across something nil template safe(obj: typed, field: untyped): untyped = if obj.isNil: return `obj`.`field` type MyNullObj = ref object x: int proc main = var nullobj: MyNullObj var notnull = MyNullObj(x: 5) echo notnull.safe(x) echo "reach here" echo nullobj.safe(x) proc main2 = var nullobj: MyNullObj var notnull = MyNullObj(x: 5) echo nullobj.safe(x) echo "cannot reach here" echo notnull.safe(x) main2() main() Run For proc that need to return something, have to set `result` in the function before hand, but `result` always has its default value so it's also ok
Re: Using a Case Statement inside a template
Very likely the of-branch cannot evaluate iterator and/or template. The `..<` not defined as proc, the workaround is template test(v: typed) = case v of low(int) .. pred(5): echo "under 5" else: echo "5 or above" Run
Re: hello world issues
> Now what if I wanted to create 32-bit-executable? In your current cmd session, invoke `set PATH=d:\your-mingw32-i686-path-bin;%PATH%` , this way the mingw32 32bit will be prioritized.
Re: cast ptr ptr to Nim array
> And good comments everywhere. That's from Ffmpeg header files comment :D , it's preferable to refer the c header file directly as the header also written with documentation there. > and sometimes there are misspelled variable ... This very likely because of `:%s/_t//g` :P , I'll fix whenever I find them. > Did you type that up by hand? Nah, I only edited from source after c2nim to make sure it's working. For several examples the binding works fine. But I'll try many more examples to make sure it's ok. > Also, the avfilter is missing there partly Will add after learning more about Ffmpeg and its APIs. TBH, I'm noob about AV-thingy here so tried to make the binding to familiarize myself with the APIs. > That seems to be the RIGHT answer. It is a pointer to an array of pointers to > the elements. Unfortunately, my bindings are still wrong and the result = nil > ... Somewhere I still have a mistake in my bindings. **tldr; Edit the source after converted using c2nim to use ``importc`` and ``header`` pragma** This was the exact case when I converted avcodec.h, avformat.h etc using c2nim. At first, I didn't use header pragma to point which header file it should be referred and when debugging it, it's always return nil (or when testing with isNil is false but crash when dereferencing the pointer). So I changed to pragma to properly point which header file and it worked ok. Even when debugging the struct name appeared too.
Re: Error: 'solve' doesn't have a concrete type, due to unspecified generic parameters.
Information of `T` and `V` already available from parent function so your
iterator doesn't have to generic. Also, if a function cannot infer from
argument, the workaround is that you have to be explicit.
proc allExactCover*[T, V](constraints: Constraints[T, V]): iterator ():
Solution[T] =
var
solution: Solution[T]
iterator nilIterator: Solution[T] {.closure.} =
yield @[]
iterator solve: Solution[T] {.closure.} =
var c = initHashSet[V]()
yield solution
try:
return solve
except KeyError:
return nilIterator
proc sdk: iterator (): Solution[Choice] =
var constraints = initConstraints[Choice, Constraint]()
return allExactCover[Choice, Constraint](constraints) # explicitly tell
the type
Run
Re: cast ptr ptr to Nim array
This worked in [my example here](https://github.com/mashingan/nimffmpeg/blob/master/fplay.nim#L44) var streams = cast[ptr UncheckedArray[ptr AVStream]](pFormatContext[].streams) Run I had issues with that too but I fixed my [FFMpeg binding](https://github.com/mashingan/nimffmpeg) too. I even also had some success with [snippet example below](https://github.com/mashingan/nimffmpeg/blob/master/ftut.nim#L64) var stream = pFormatContext[].streams[i] Run
Re: Distinct for indices, is it good library Api?
> What do you mean? If I understand correctly, you defined the Node with information of incoming / outgoing Edge type Node*[N] = object ## The graph's node type. weight*: N ## Associated node data. next: array[2, EdgeIndex] ## Next edge in outgoing and incoming edge lists. Run This way, you only have 1 Edge for each, 1 for incoming and 1 for outgoing. Unless your graph specifically only as a one line flow, a node should be able to have several nodes incoming and outgoing but you only defined it as an array of two Edge member. If it's seq, you can add it later based on new graph connection or any info. Simply changing the definition into seq should somehow solve the limitation of current definition. But since it's in development phase, you would recognize it the more you develop it, that's why I mentioned "will be unused". CMIIW
Re: Distinct for indices, is it good library Api?
IMO, It's not worthy to make it distinct, moreover, you should use generic instead of int for nodes label. Unrelated to the question, you should keep the Node definition is literally as a node, and keep Edge definition is the connection from Node1 and Node2. The array of two nodes index for incoming/outgoing will be unused the more you add APIs to your graph.
Re: Problem with C interop/X11 bindings
> there is no nil, it reports wrong size. I remember something when doing ffmpeg c binding. At first I wrote the binding without adding the header pragma, and just simply importc pragma only. In the c header file, that particular object actually internal struct that isn't included in dev headers, and it's there just as to declare the type/struct. I debugged that and it was returning nil or something that not nil but would crash/segfault if I tried to deref it. After adding the header pragma then it ran smoothly and when debugging, the gdb returning the correct struct name. Idk if it's related or not, but you can try looking that part.
Re: Object Variants and redefinition of labels or reusbility of field names
Another workaround type # The 3 notations refer to the same 3-D entity, and some coordinates are shared CoordinateSystem = enum csCar, # Cartesian(x,y,z) csCyl, # Cylindrical (r,φ,z) csSph # Spherical(ρ,θ,φ) Coordinates = object cs: CoordinateSystem # cs is the coordinate discriminator coor1, coor2, coor3: float # keep this part private CoorException* = ref object of Exception proc x(p: Coordinates): float = if p.cs != csCar: raise newException(Defect, "Only available for Cartesian.") p.coor1 proc `x=`(p: var Coordinates, xval: float) = if p.cs != csCar: raise newException(Defect, "Only available for Cartesian.") p.coor1 = xval # do the same with y, and z, should be succint with templates proc φ*(p: Coordinates): float = if p.cs == csCar: raise newException(Defect, "Cartesian doesn't support φ field.") elif p.cs == csCyl: result = p.coor2 elif p.cs == csSph: result = p.coor3 # do the same with other field var car1 = Coordinates(cs: csCar, coor1: 1.0, coor2: 2.0, coor3: 3.0) echo car1.x car1.x = 1.5 echo car1.x var car2 = Coordinates(cs: csCyl, coor1: 1.0, coor2: 2.0, coor3: 3.0) echo car2.φ Run Read more about it in [manual page here](https://nim-lang.github.io/Nim/manual.html#procedures-properties)
Re: Object Variants and redefinition of labels or reusbility of field names
workaround
import strformat
type
# The 3 notations refer to the same 3-D entity, and some coordinates are
shared
CoordinateSystem = enum
csCar, # Cartesian(x,y,z)
csCyl, # Cylindrical (r,φ,z)
csSph # Spherical(ρ,θ,φ)
Cartesian = object
x, y, z: float
Cylindrical = object
r, phi, z: float
Spherical = object
rho, theta, phi: float
Coordinates = object
case cs: CoordinateSystem: # cs is the coordinate discriminator
of csCar:
car: Cartesian
of csCyl:
cy: Cylindrical
of csSph:
sph: Spherical
proc `$`(point: Coordinates): string =
case point.cs
of csCar: result = &"(x: {point.car.x:5.2f}, y: {point.car.y:5.2f}, z:
{point.car.z:5.2f})"
of csCyl: result = &"(r: {point.cy.r:5.2f}, φ: {point.cy.phi:5.2f}, z:
{point.cy.z:5.2f})"
of csSph: result = &"(ρ: {point.sph.rho:5.2f}, θ: {point.sph.theta:5.2f},
φ: {point.sph.phi:5.2f})"
Run
Re: Problem with C interop/X11 bindings
Idk too, but try to wrap the functionality in some proc like main or anything and just call that proc. Another thing, you can always use gdb to check each variable which one has nil.
Re: How to use private variables when you put all types in one module
> And i dont want to mix the implementation code with type declaration code. I > need to split as much code as possible. In different modules or in different files? If in different modules, as for now, everything exported are visible to other modules that import it. If it's only needed in different file, use [include statement](https://nim-lang.github.io/Nim/manual.html#modules-include-statement)
Re: How to use private variables when you put all types in one module
If you need to access the field from other modules, then it's literally not private anymore. If you have specific function that have to work with that private field, then implement it in that common module and have that function exported. If you want to have read only for that specific field, implement the proc for it like proc myFieldName(o: TheObject): FieldType = o.myFieldName Run Well, basically, there's no literally should have or shouldn't have when organizing it, just need some sense/reasonable organization.
Re: how to create a generic type with constraints?
Checking with
[compiles](https://nim-lang.github.io/Nim/system.html#compiles%2Cuntyped)
should enough
when compiles(hash(a)): # a is the T object
doWith(a)
else:
{.error: "need hash implementation of " & T.type.}
Run
It's checked during compile-time.
Re: What’s your favorite programming language and why?
Same here, love Erlang's philosophy too :D
Re: Force mutable Seq returns
Perhaps you're looking for [var return type](https://nim-lang.github.io/Nim/manual.html#procedures-var-return-type) ?
Re: What is the difference between "writeFile" and "newFileStream" and "write"?
AFAIK, `Stream` is usually when you're dealing with bytes; whether opening binary files, or reading/writing network bytes stream, or reading/writing bytes to file etc. Especially for writing bytes, just like in the example.
Re: Creating a type that is a non-contiguous subset of char?
since b is declared as WASDLetters , it's inferred so. But since it's WASDLetters you won't be able to ord(b) and it's detected during compile-time checking.
Re: More elegant way to "invert" a table (hash map, dictionary)
Dunno if more elegant or not, but you can try using mapIt
import tables, sequtils
var int2str = {0: "Zero", 1: "One", 2: "Two", 3: "Three"}.toTable
var str2int = toSeq(int2str.pairs).mapIt((it[1], it[0])).toTable
Run
Re: How to write a shared(static in c++) proc in a type ?
proc in Nim is static
Re: Newbie question: downloading multiple files using async httpclient
Yes, it's whether you to wait with asyncCheck or go with future.failed is up to application. But the idea is same.
Re: Newbie question: downloading multiple files using async httpclient
the problem that the client cannot be shared to other download
import httpClient, asyncdispatch
proc download(url: string): Future[string] {.async.} =
await newHttpClient().getContent(url)
}
proc downloadAll(urls: seq[string]) {.async.} =
var asyncresult = newseq[Future[string]](urls.len)
for i, url in urls:
asyncresult[i] = download url
await all(asyncresult)
let urls = @[
"http://127.0.0.1:5000/json;,
"http://127.0.0.1:5001/json;,
"http://127.0.0.1:5002/json;,
]
waitFor downloadAll(urls)
Run
Re: httpClient url with the spaces
[encodeQuery](https://nim-lang.org/docs/uri.html#encodeQuery%2CopenArray%5B%5D) How to get the documentation based on keyword/name? 1. Open [the index](https://nim-lang.org/docs/uri.html#encodeQuery%2CopenArray%5B%5D) page. 2. Search the page there with `encodeUrl`. 3. See available procs related to Uri by clicking the found keyword. Hope it helps.
Re: Newbie experience with the documentation
Trick to find all procedures that return SomeType: `:) SomeType`
Re: Confusion on implicit integer conversion.
_tldr; if the size of integer is important, always opt to explicit conversion_ * * * you can define your own `+` operator for your case proc `+`(x: uint16, y: uint32): uint32 = x.uint32 + y Run But then the definition then become tedious if you have to define another with proc `+`(x: uint32, y: uint64): uint64 = x.uint64 + y Run again and again. So the `+` is defined as generic. Since generic doesn't know which type should it bind to, so it's logical choice to bind to first argument.
Re: Jester question: passing gcsafe variable into routes
Played the idea of pool connections and wrote some example in [gist here](https://gist.github.com/mashingan/7532bd89c4e3bde6526a896a3ae611b7).
Re: Need debugging help
Can you try changing [line 236](https://github.com/pb-cdunn/nim-help/blob/master/raptor_db.nim#L236) with `var sr = SequenceRecord()` ? I'm not sure but maybe what you're doing is scope-escaping memory? That `var sr: SequenceRecord` only available in the stack and it got destroyed after you copy (or move?) to `result.seqs.add(sr)` I cannot run it, currently don't have available linux box currently.
Re: asyncnet and reading from multiple socks
> send connect three sockets and read from each of the asynchronously?
like this?
import asyncnet, asyncdispatch, strutils, random
proc genAddr(): string =
randomize()
var
ip0 = rand(1..255)
ip1 = rand(255)
ip2 = rand(255)
ip3 = rand(255)
(join([$ip0, $ip1, $ip2, $ip3], "."))
proc main() {.async.} =
var
sock0 = newAsyncSocket()
sock1 = newAsyncSocket()
sock2 = newAsyncSocket()
res0: string
res1: string
res2: string
host0 = genAddr()
host1 = genAddr()
host2 = genAddr()
await sock0.connect(host0, Port 22)
await sock1.connect(host1, Port 22)
await sock2.connect(host2, Port 22)
let
read0 = sock0.recvLine()
read1 = sock1.recvLine()
read2 = sock2.recvLine()
#[
var
read0Complete = false
read1Complete = false
read2Complete = false
while true:
if read0Complete and read1Complete and read2Complete:
break
if read0.finished and not read0.failed and not read0Complete:
read0Complete = true
res0 = read read0
elif read1.finished and not read1.failed and not read1Complete:
read1Complete = true
res1 = read read1
elif read2.finished and not read2.failed and not read2Complete:
read2Complete = true
res2 = read read0
echo res0
echo res1
echo res2
]#
# easier, if we just need to wait all results
for line in await all(read0, read1, read2):
echo line
waitFor main()
Run
> Issue I'm seeming to have is timeout never occurs upon false connections
Try to wrap with connection future
[withTimeout](https://nim-lang.github.io/Nim/asyncdispatch.html#withTimeout%2CFuture%5BT%5D%2Cint)
like
let
conn1 = sock0.connect(host, Port 22).withTimeout(1000)
conn2 = sock1.connect(host, Port 22).withTimeout(1000)
conn3 = sock2.connect(host, Port 22).withTimeout(1000)
if not await(conn1) or not await(conn2) or not await(conn3):
echo "timeout reached in any connection"
Run
_#untested_
Re: Erroneous values returned from Nim’s C foreign function interface.
I'm not sure but after I see in your wutilc
char buffer[INET6_ADDRSTRLEN];
char *get_from(...) {
\\
return buffer;
}
Run
I guess it's the problem with global variable; you should change the c api too
void *get_from(struct utmpx *ut, char* outaddr) {
}
Run
and call it in nim
#
var addrbuf = alloc0(INET6_ADDRSTRLEN)
getfrom(u, addrbuf)
# ...
dealloc(addrbuf)
Run
Re: D templated codeblocks
> (calling again with the same type param does not create a new code block) This doesn't seem good idea.
Re: dynamic lib works properly when interfacing with python, fails with nim
Try `cdecl` calling convention or others like mentioned in [manual page](https://nim-lang.github.io/Nim/manual.html#types-procedural-type)
Re: CORS in Jester
Maybe your client-side hit with pre-flight request.
Re: Simple coroutine like Python generator send()?
Read about iterator in [manual](https://nim-lang.github.io/Nim/manual.html#iterators-and-the-for-statement) [playground](https://play.nim-lang.org/index.html?ix=1MaK) proc countTo(maxi: int): iterator(x = 1): int = result = iterator(x = 1): int = var i = 0 while i <= maxi: i.inc x yield i var itx3 = countTo 3 echo itx3(2) if not itx3.finished: echo itx3() Run
Re: How to parse the timezone from a date/time string to a `TimeZone` type variable?
something like this
import times, strutils, sugar
let
dtStr = "2019/06/06 18:17:43 +02:00"
dt = parse(dtStr, "/MM/dd HH:mm:ss zzz")
myM10 = newTimezone("M-10",
(x: Time) => ZonedTime(utcOffset: Hours.convert(Seconds, 10), time: x),
(x: Time) => ZonedTime(utcOffset: Hours.convert(Seconds, 10), time: x))
dtOffset = -1 * dtStr.rsplit(maxsplit=1)[1].split(":",
maxsplit=1)[0].parseInt
dtTz = newTimezone("DtTz",
(x: Time) => ZonedTime(utcOffset: Hours.convert(Seconds, dtOffset),
time: x),
(x: Time) => ZonedTime(utcOffset: Hours.convert(Seconds, dtOffset),
time: x))
dtOrig = dt.inZone(dtTz)
dtMy = dt.inZone(myM10)
echo dt
echo dt.timezone
echo dt.utcOffset
echo ""
echo dtOrig
echo dtOrig.timezone
echo dtOrig.utcOffset
echo ""
echo dtMy
echo dtMy.timezone
echo dtMy.utcOffset
Run
note:
1. offset should really calculate hours and minutes offset
2. idk why it should be reverted with -1 for setting the timezone (maybe
because of time-relativity)
3. you can write an array that populate with timezone at 1 hour interval at
compile-time
4. (or) you can provide some external timezone data and read it at
compile-time or run-time
IMO, the current times module is more pleasant to work with compared to earlier
version, kudos for the dev :3
Re: How to parse the timezone from a date/time string to a `TimeZone` type variable?
there's [utc](https://nim-lang.github.io/Nim/times#utc%2CDateTime) proc for what you want import times let dtStr = "2019/06/06 18:17:43 +00:00" dt = parse(dtStr, "/MM/dd HH:mm:ss zzz").utc echo dt Run
Re: Trouble when splitting in a CLI application
parseopt of course can extract the argument too import parseopt let cmdline = "config create \"a configuration\"" var opt = initOptParser(cmdline) for kind, key, val in opt.getOpt(): case kind of cmdArgument: echo "argument: ", key else: discard Run
Re: about Nim compiler parameters
> -d:ssl This is same with `--define:ssl` , two hyphens is long option while single hyphen is short option. This `--define` option is to define a compile-time variable ala `#DEFINE` in C for example you define 'goThisWay' when compiling then you can use it in code when defined(goThisWay): # all codes that will be compiled else: # alternative when you want other codes Run Another use is explained in this [part of manual](https://nim-lang.github.io/Nim/manual.html#implementation-specific-pragmas-compile-time-define-pragmas)
Re: Is there a 'protected' or module-local scope modifier?
elaborate example case please.
Re: Metaprogramming and wrapping C libraries
also you can use
[quote](https://nim-lang.github.io/Nim/macros.html#quote%2Ctyped%2Cstring) proc
which easier to use
macro compileFiles(path: static[string], files: untyped): untyped =
result = newStmtList()
for f in files:
let file = newLit(path & $f)
result.add quote do:
{.compile: `file`.}
compileFiles("/base/path/"):
"a.c"
"b.c"
"c.c"
Run
Re: Nim false redefinition error
try remove nimcache folder
Re: Thread and socket functions issue
compile with option `--threads:on`
Re: Conditional compilation in imported module based on constant?
> Can I specify binary-specific defines for the nimble build process?
You can specify which kind of binary built with nimble task. See
[here](https://github.com/nim-lang/nimble#creating-packages)
You can also make a config file specific to your nim file so the name is
_yourfile.nim.cfg_ and put the options in it like
-d:it_is_for_algo{1,2}
Run
So whenever `nim c yourfile.nim` is invoked, it automatically add options
specified in your config file.
Re: New to Nim, Made Something to Feed It
> I’ve used the to(type) macro in other code, but is there a reason to use it > over getStr()? Well, it's convenience, because most of times it's unwieldly to get all the fields one by one
Re: New to Nim, Made Something to Feed It
Welcome :) Additional info, you can use [to](https://nim-lang.github.io/Nim/json.html#to.m%2CJsonNode%2Ctypedesc) macro to simplify conversion from _JsonNode_ to specified type ;)
Re: Nim vs D
perhaps what you want is [quote](https://nim-lang.github.io/Nim/macros.html#quote%2Ctyped%2Cstring) proc?
Re: WideCString -> seq conversion
Have you tried of `runes` in `unicode` module? It's template that to convert `string` to `seq[Rune]`
Re: Nimongo comparison (i.e. $gt) queries
> `"{$gt:10}".toBson`
This is string, not bson embedded object, what you need is
let query = %{
"temp": {
"$gt": 10
}
}
Run
Re: Not-so-distinct types
If the mapping is fixed, you can use [subrange](https://nim-lang.org/docs/manual.html#types-subrange-types) types. Although the base type is same, you can define like type Row1 = range[ 0 .. 71 ] # assuming row has 72 bytes Row2 = range[ 72 .. 143 ] Run Maybe like that?
Re: Not-so-distinct types
Is [distinct](https://nim-lang.org/docs/manual.html#types-distinct-type) not what you need? You can define the needed operations from its base type using `borrow` pragma so you don't have to cast/coerce every time you use it Also, I did what @cdome suggested, defining `converter` s and it works like charm. I have several subtype and using converters to convert back and forth between the base type and its subtype.
Re: pegs module: how to use captures in enter/leave procs?
Haven't tried the event parser, but if only capturing the needed text I usually use `find` proc var buffer = newseq[string](10) # crash if the seq not enough if example =~ grammar: discard example.find(grammar, buffer) echo buffer # will print # ["1", "2", "3", "", "", "", "", "", "", ""] Run
Re: Is allowing non-matching types for assignment overloading in the development timeline?
Perhaps like this type IntAp = object setInts: array[0 .. 2, int] converter toIntAp(n: int): IntAp = let ints = [n, 0, 0] IntAp(setInts: ints) let n: IntAp = 5 Run
Re: Nim vs V language
My (insignificant) 2cent ;) > V and Nim are very different. One of V's main philosophies is "there must be > only one way of doing things". This results in predictable, simple, and > maintanable code. This is fallacy. Bad written code is bad, no matter what syntax is. The only thing that make the software maintainable is documentation. Predictability is something resulted by how clear the program (or data) flow from start to end. Not the syntax of anything or what. Simplicity comes after several (endless) iteration of how we write the software. Hoping to write program with simplicity at first shot? Without even understanding the nature of problem we want to solve? Well, good luck with that :D
Re: How to compile and run a Nim program on the Android?
try more the recent post [https://forum.nim-lang.org/t/3575#22318](https://forum.nim-lang.org/t/3575#22318)
Re: How to compile and run a Nim program on the Android?
Your phone must be root-ed to do that.
Re: Please tell me about jester's "tmpl" files.
It's known as source-code filter and you can read the documentation [here](https://nim-lang.org/docs/filters.html) > Can I re-render the page of tmpl without having to re-compile nim. You can't, cmiiw.
Re: What is the best way to run a nim program as daemon?
handle with [setControlCHook](https://nim-lang.org/docs/system.html#setControlCHook%2Cproc%29) proc
Re: What is the best way to run a nim program as daemon?
I usually make the executable as service using [this reference](https://gist.github.com/bcap/5397674)
Re: Query Filepath for owner and group ID or name
using [fstat](https://nim-lang.org/docs/posix.html#fstat%2Ccint%2CStat) ? import posix var f = open "/home/jacobsin/test.txt" var s: Stat discard fstat(cint f, s) Run
Re: Config file location for loadConfig
There's [getAppDir](https://nim-lang.org/docs/os.html#getAppDir%2C) proc
Re: Noob question: proper way to read binary files byte by byte
memfile is basically loading all content to memory, cmiiw
Re: Noob question: proper way to read binary files byte by byte
use [atEnd](https://nim-lang.org/docs/streams.html#atEnd%2CStream) to check whether it's ended or not and use [getPosition](https://nim-lang.org/docs/streams.html#getPosition%2CStream) for its current position. import os, streams var fs = newFileStream(paramStr(1), fmRead) while not fs.atEnd: var one_char = fs.readChar() echo one_char Run
Re: std::pair, std::make_pair, std::find, std::distance in Nim?
You can iterate and check manually like var intpair = newseq[(int, int)]() texture: int lightmap: int for thepair in intpair: if thepair[0] == texture and thepair[1] == lightmap: doSomething((texture, lightmap)) Run or you can use define type IntPair = tuple a: int b: int proc `==`(a, b: IntPair): bool = a.a == b.a and a.b == b.b var texture: int lightmap: int intpairs = newseq[IntPair]() thepair = (texture, lightmap) pos = intpairs.find thepair if pos != -1: doSomething(thepair) Run
Re: Convert string to char
You can't generically represent `string` as `char`, but for your specific case,
you can do it like this:
import options
proc chr(s: string): Option[char] =
if s == "\\n": some('\n')
else: none(char)
let nlinerepr = r"\\n".chr
if nlinerepr.isSome:
echo nlinerepr.some
let otherstr = "hello".chr
if otherstr.isNone:
echo "no char repr"
Run
Re: Screencast Series Ideas
> I always get tripped up on "damn, this is all classes and objects, how to I > do the same thing in Nim?" You need to change the perspective of the definition from AS to HAS, but `ref object of` is kinda AS too, cmiiw. Thanks for link video btw :) @ryuukoposting , 1st video is nice, waiting for the next videos :D
Re: template does not create methods?
Change the return template from `int` to `untyped` . I usually think `untyped` as `unchecked` for easy understanding but let's wait for other to explain better ;)
Re: Fuzzy matching on table keys
Add `hash` function and equality operator `==` for custom key.
import tables, hashes
type
Fn = proc (args: varargs[string]): int
FnSignature = tuple
name: string
arity: int
argTypes: seq[string]
proc hash(fns: FnSignature): Hash = fns[0].hash
proc `==`(a, b: FnSignature): bool = a[0] == b[0]
var signatures = newTable[FnSignature, Fn]()
signatures.add(("print", 1, @["any"])) do (args: varargs[string]) -> int:
discard
echo signatures[("print", 1, @["string"])]("whatev")
Run
Re: How to "install" a newly built Nim on a directory?
import std/math
Re: gladloadgl
your `gladLoadGL` definition is `proc gladLoadGL(load: proc): bool` but you invoked `gladLoadGL()` without argument
Re: How to implement a "Walrus" operator like in python 3.8 in Nim?
> ... but if you really want, you can use converters. ... but if you can, you should avoid using `int` for `bool`
Re: vecctor items iterator
items iterator is for immutable object, for mutable one, use mitems
Re: "Nim needs better documentation" - share your thoughts
A. > 1\. Do you think there should be more links to the existing (user-created) > resources? If so, which ones? Yes, but I don't know. > 2\. What resources are needed? Video tutorials, how-to tutorials for some > field X (what is X for you?), cookbook (there is/was one, but it seems it is > not updated anymore), etc. Complete how-to tutorials: web development, machine learning with _Arraymancer_ , mobile dev. Those are niche topics currently, the easier and more complete the tutorial should make entry barrier lower for people to use/try Nim > 3\. Have you used Rosetta Code for learning how to do things in Nim? Do you > find it useful? Yes, but quite rarely. Usually when I have no specific thing to do. > 4\. Have you used code practice sites like Exercism to learn Nim (or some > other language)? Do you think they are useful for learning the language? (Or > in Nim case: would they be useful if they had more Nim exercises availbable?) Never used it. Yes, I think it's useful for learning Nim. B > 5\. Can you show us the examples of 'good documentation' (GD, later in the > text) in other programming languages? Python documentation, Rust (but it's introduction book, not the their documentation, strangely, I found Nim documentation is easier to read than Rust's, it's just need some example and elaborate explanation on how to use the module/libs) > 6\. What does the GD consist of? For each module, a general explanation of > what it does, code examples of its usage? Long explanations of each > function/type/constant? Lots of examples for each function? Links to other > modules? Something else? Yes pretty much like this. > 7\. What is you major pain point when using Nim documentation? Is it hard to > find the module(s) which would be useful to you? Can you understand what a > function does based on the description and the example? Are (most of the > time) the examples missing or not informative enough? Nothing major but need time to browse the list and getting familiar with any libs available (for the first time), afterward I usually just head to "the_index". Sometimes I understand, mostly not. I understand if I have been working with that libs quite often, but when first time using it, need time to digest the information. (but it's normally like that right?) _Asyncdispatch_ and _strscans_ has elaborate explanation, as for _asyncdispatch_ unfortunately that's still not enough for me on how to use it effectively :/ > 8\. Is there any Nim module which satisfies your criteria for GD? (It is good > as it is, doesn't need any improvements) If we think the GD is like Python's doc, then none. But pretty much the current doc is mostly self-explainable for me. > 9\. Can you show us Nim modules which, in your opinion, have very good > documentation? (Only small improvements are needed to make it GD) [strscans](https://nim-lang.org/docs/strscans.html) > 10\. Are you willing to help making Nim documentation better? :) More than willing, just need the documentation, ehem I mean guide :D , to contribute to documentation
Re: Nim and Project Euler
This is my opinion so I have no "hard-data" to backup, I think most (if not all) Nim users are people who already have experience with other languages. People will gravitate to something that have most lib, most tutorial, most documentation, and most easiest for solving their real-life problems (e.g. Python which have sheer amount of libs and documentation/tutorial) This also my opinion, I think another reason why people solving problems in Project Euler (other than recreation ofc) is to get familiar with syntaxes. Means, few people solving problem in Project Euler using Nim shouldn't something that alarming, it's just Nim syntax is so easy that they can pick it up easily. (Again, this is my opinion).
Re: Some nim builtin libs not doing enough error checking?
Same here, I prefer checked it first with [dirExists](https://nim-lang.org/docs/os.html#dirExists%2Cstring) than immediately walk it.
