Table.withValue(): .. else: support

[Menduist]

This PR adds support for

    t.withValue(522, value):
      doAssert false
    else:
      # block is executed when `key` not in `t`
      discard

(previously a do was required)

[metagn]

Could also do:

import macros

macro unwrapElse(ex: untyped): untyped = # maybe goes somewhere in standard library
  if ex.kind == nnkElse:
    result = ex[0]
  else:
    result = ex
    
template foo(a, b, c) =
  if a:
    b
  else:
    unwrapElse(c)
    
foo false:
  echo "a"
else:
  echo "b"

[Menduist]

Done, though I don't understand the CI failure, seems to be caused by IC trying to use the macro at runtime?

[metagn]

Probably not worth it to investigate IC, the original way is good enough. Though a way to refactor it might be:

template withValueImpl(..., elseBlock) =
  # original withValue

macro withValue*(..., originalElseBlock) =
  let elseBlock = if originalElseBlock.kind == nnkElse: originalElseBlock[0] else: originalElseBlock
  result = getAst(withValueImpl(..., elseBlock))

so the actual implementation of withValue is a bit more visible.

[Menduist]

The original way also caused the same CI failure, unfortunately

[github-actions]

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[github-actions]

This pull request has been marked as stale and closed due to inactivity after 395 days.