Nim: Cannot discard result of staticExec

[TheSimpleZ]

I cannot discard the result of staticExec.

Example

discard staticExec(r"echo ""hello""")

Current Output

test.nim(1, 19) Error: 'staticExec' can only be used in compile-time context

Expected Output

Successful compilation

Possible Solution

It works if i write:

const s = staticExec(r"echo ""hello""")

Additional Information

I'm just trying to learn the language and find this behavior unexpected.
Why would the program stop compiling if i discard the return value?

$ nim -v
Nim Compiler Version 1.0.6 [Linux: amd64]

[Clyybber]

static: discard staticExec(r"echo ""hello""")
should work.

[TheSimpleZ]

Oh, it does. Thanks! Could you please explain why it behaves like this?

[Clyybber]

Hmm, I think its because discard does not try to evaluate its arguments in a static context implicitly.
I'm not sure if its intended, so I will leave this open.

[krux02]

If you the following in system.nim

proc gorge*(command: string, input = "", cache = ""): string {.
  magic: "StaticExec".} = discard

proc staticExec*(command: string, input = "", cache = ""): string {.
  magic: "StaticExec".} = discard

with:

proc staticExecImpl(command,input,cache: string): string {.
  magic: "StaticExec".} = discard

proc gorge*(command: string, input = "", cache = ""): string {.compileTime.} =
  staticExecImpl(command,input,cache)

proc staticExec*(command: string, input = "", cache = ""): string {.compileTime.} =
  staticExecImpl(command,input,cache)

Your code will work (comments omitted). The magic is in the compileTime pragma. Sure this can also be fixed by fixing the staticExec magic.

[genotrance]

This fix does not work since gorge() now runs in $nim/lib since that's where system.nim is. Any calls to gorge() that use relative path break as the PR did.