`repr` doesn't work with hex literals (and other `repr` bugs now fixed)

[timotheecour]

bugs

• do: renders badly => fix #14850: repr now correctly renders do #17623 and refs #17292 fix repr with do: #17449
• bug 2: (discard) renders badly => refs #17292 fix repr: (discard) now does't render as discard which gave illegal code #17455
• bug 3: hex numbers render badly, silently giving wrong results, eg 0xFFFFFFFF, see Example 1 below
• bug 4: nnkAccQuoted renders badly, see Example 2 below => repr: fix rendering of 'big, =destroy etc #17624
• bug 5: *a: b renders badly, which might be due to a parser error, see Example 3

Example 1

when true:
  macro deb(a) =
    echo a.repr

  deb:
    let f = () => (discard)
    f()
    let x = 0xffffffffffffffff
    template fn(body: untyped): untyped = true
    doAssert(fn do: nonexistant)
    template foo(x, y) =
      x
      y
    foo:
      discard
    do:
      discard

Current Output

let f = () =>
  discard
f()
let x = 0xFFFFFFFF
template fn(body: untyped): untyped =
  true

doAssert(fn:
  nonexistant)
template foo(x, y) =
  x
  y

foo(
  discard ):
  discard

Expected Output

let f = () =>
  (discard)
f()
let x = 0xffffffffffffffff
template fn(body: untyped): untyped =
  true

doAssert(fn do: nonexistant)
template foo(x, y) =
  x
  y

foo:
  discard
do:
  discard

Example 2

repr doesn't work with nnkAccQuoted:

import macros
macro deb(a) =
  echo a.repr
deb:
  proc `=destroy`(a: Foo) = discard
  proc `'foo`(a: string): int = discard

prints:

proc `= destroy`(a: Foo) =
  discard

proc `' foo`(a: string): int =
  discard

the culprit is the spaces inserted here in renderer.nim:

  of nkAccQuoted:
    put(g, tkAccent, "`")
    if n.len > 0: gsub(g, n[0])
    for i in 1..<n.len:
      put(g, tkSpaces, Space)
      gsub(g, n[i])
    put(g, tkAccent, "`")

Example 3

• see *a: b parsed wrong in repr doesn't work with hex literals (and other repr bugs now fixed) #17292 (comment)
  (should be moved to a different bug)

Additional Information

• 1.5.1 b8c04bd
• code is under renderer.nim; eg renderModule is buggy
• affected runnableExamples until fix #13491 #17279 runnableExamples now don't get lost in translation #17282

From pietroppeter/nimib#20 - might this issue be related to this bug?

import std/macros

macro testOut(x: untyped) = 
  echo treeRepr x
  echo repr x

testOut:
  *header: {headers}

Currently the renderer's output is *header which is obviously wrong

[timotheecour]

I think it's a separate issue, unrelated to repr (repr shows badly but that seems like a symptom)

@Araq isn't that a parser bug?

when true:
  import std/macros

  macro testOut(x: untyped) = 
    echo treeRepr x
    echo lispRepr x
    echo repr x

  testOut:
    *a: b

StmtList
  Prefix
    Ident "*"
    Ident "a"
    StmtList
      Ident "b"
(StmtList (Prefix (Ident "*") (Ident "a") (StmtList (Ident "b"))))

*a

how come Prefix has 3 children instead of 2?

[Araq]

how come Prefix has 3 children instead of 2?

I think the colon is parsed much like a do: in this case so it adds a third child. Definitely something we need to investigate. :-)