@mantielero Nim does not support creating functions at runtime. Generally,
compiled languages such as Nim get around this by compiling a source file into
a DLL and then loading that. It's unfortunately not as simple as you want it to
be.
The library @Hlaaftana linked to is being created by @shashlick (which is
probably not ready yet) and it will likely allow an easy interface for creating
plugins in Nim.
In the meantime, this is how you would do it. Put the following 3 files in the
same directory.
# english.nim
proc greet*(): string {.exportc, dynlib, cdecl.} =
result = "Hello!"
Run
Compile the above with `nim c --app:lib english.nim`. This will result in
`libenglish.dylib` on Mac, `libenglish.so` on other Unix, and `english.dll` on
Windows.
# french.nim
proc greet*(): string {.exportc, dynlib, cdecl.} =
result = "Hello!"
Run
Compile the above with `nim c --app:lib french.nim`. This will result in
`libfrench.dylib` on Mac, `libfrench.so` on other Unix, and `french.dll` on
Windows.
# testplugin.nim
import dynlib
type
greetFunction = proc(): string {.nimcall.}
proc main() =
echo "Enter a language: "
let lang = stdin.readLine()
let lib = case lang
of "french":
loadLib("./libfrench.dylib") # Rename for your OS
else:
loadLib("./libenglish.dylib") # Rename for your OS
if lib == nil:
echo "Error loading library"
quit(QuitFailure)
let greet = cast[greetFunction](lib.symAddr("greet"))
if greet == nil:
echo "Error loading 'greet' function from library"
quit(QuitFailure)
let greeting = greet()
echo greeting
unloadLib(lib)
main()
Run
Then compile and run the above with `nim c -r testplugin.nim`. You should get a
prompt to enter your language. Enter "french" for "Bonjour!" or anything else
for "Hello!".
You could easily extend the above to get a function name from a list of plugin
paths. Hope this is helpful to you.
