anonymous proc definition not allowed in statement position

[mrgaturus]

creating a proc from a template using this elegant syntax is not possible due parser limitations

Example

type
  MyProc = proc(a, b: int32): int32 {.nimcall.}

template mad(c: int32): MyProc =
  proc (a, b: int32): int32 {.nimcall.} = # -- Syntax Error? --
    (a + b) * c

let fn = mad(2)
echo fn(10, 10) # 40

Actual Output

Error: identifier expected, but found '('

Expected Output

40

Possible Solution

a workaround requires an extra symbol

template mad(c: int32): MyProc =
  let result =
    proc (a, b: int32): int32 {.nimcall.} =
      (a + b) * c
  # Extra Symbol Involved
  result

References

works on nim

[zerbina]

Anonymous proc definitions being a syntax error not only affects templates (I've updated the title to reflect this), but other contexts as well.

The current grammar (and parser) state that a routine definition where a complexOrSimpleStmt is expected must be named, though it would make sense to lift this restriction.