followup custom literals

[timotheecour]

• addresses left-over TODO's for [superseded] Adding support for user-defined number suffixes #17020 and custom integer literals #17489
• add tests
• bring back a test
• condsyms: add defineSymbol("nimHasCustomLiterals")

[Clyybber]

Don't make it a template and use a directly.

[timotheecour]

this avoids a copy; and lent is not possible.

EDIT: template doesn't actually avoid the copy in this case because of the case expression...

[timotheecour]

found a solution that avoids a copy (and uses a proc)

[Araq]

Come on... Instead try something like:

template strValProp*(a: PNode; prop: untyped): bool =
  case a.kind
  of nkStrLit..nkTripleStrLit: prop a.strVal
  of nkSym: prop a.sym.name.s
  of nkIdent: prop a.ident.s
  else: false

[timotheecour]

I've tried (see option 2 and option 3, a variant of your proposal), it's objectively worse:

• option 2: causes a copy, which is what i wanted to avoid in first place
• option 3: causes code bloat, like multiple yield statements in inline iterators

and both options lead to more complex client code. How would you translate code like this with option 2 or 3?

echo (n[1].getStrVal, n[2].getStrVal, n.kind)

option 2: your suggestion

template strValProp*(a: PNode; prop: untyped): bool =
  let a2 = a # prevent double evaluation bugs
  case a2.kind
  of nkStrLit..nkTripleStrLit: prop a2.strVal
  of nkSym: prop a2.sym.name.s
  of nkIdent: prop a2.ident.s
  else: false

n[1].getStrVal.startsWith('\'')

gets replaced by:

from std/sugar import `=>`
n[1].strValProp((it: string) => it.startsWith('\''))

option 3: your suggestion modified

template strValIt*(a: PNode; op: untyped): bool =
  let a2 = a # prevent double evaluation bugs
  case a2.kind
  of nkStrLit..nkTripleStrLit:
    template it: untyped {.inject.} = a2.strVal
    op
  of nkSym:
    template it: untyped {.inject.} = a2.sym.name.s
    op
  of nkIdent:
    template it: untyped {.inject.} = a2.ident.s
    op
  else: false

n[1].getStrVal.startsWith('\'')

gets replaced by:

n[1].strValIt(it.startsWith('\''))

which isn't too bad in this case, but there's no simple equivalent in other cases, eg:

echo (n[1].getStrVal, n[2].getStrVal, n.kind)

[Araq]

So that we can proceed, please undo the changes to the following files for the time being:

• compiler/ast.nim
• compiler/msgs.nim
• compiler/renderer.nim
• tests/views/tcan_compile_nim.nim