Parametrized types do not allow spaces after "("

[Mingun]

Following KSY raises error until space between ( and true will be deleted:

meta:
  id: type_references
seq:
  - id: field
    type: 'type::sub( true , 2 )'
types:
  type:
    types:
      sub:
        params:
          - id: par
            type: bool
          - id: par2
            type: u1
        seq: []

I think that is unnecessary restriction and it can be eliminated. The root of the problem is that parametric type parsing is partially done in manually, and partially using expression language. It is much easier to always parse the entire string as an expression, at the same time you can:

• allow spaces between ::
• allow spaces in begin and at end of string
• allow spaces before (

Now corresponding PEG rule for type references is:

parseTypeRef = name ("::" name)* ("(" args _ ")")? EOS;
args = expr (_ "," _ expr)*;
...

But it would be:

parseTypeRef = _ name (_ "::" _ name)* _ ("(" _ args _ ")" _)? EOS;

[GreyCat]

Makes sense, thanks for reporting it! It's not a super high priority, but hopefully we'll get to fix it sometime in the future.

[generalmimon]

@Mingun Thanks for this research! I've also encountered this problem in my BMP spec on these lines (image/bmp.ksy:148-151):

        type: 'color_table(
            not header.is_core_header,
            header.extends_bitmap_info ? header.bitmap_info_ext.num_colors_used : 0
          )'

This fails in the devel Web IDE with the following exception:

io.kaitai.struct.format.YAMLParseException: /types/bitmap_info/seq/3: unable to find type 'color_table(
not header.is_core_header,
header.extends_bitmap_info ? header.bitmap_info_ext.num_colors_used : 0
)', searching from bmp

However, KSC under JVM (using SnakeYAML library) works fine:

$ ksc --debug -t javascript --verbose file -I . image/bmp.ksy
parsing image\bmp.ksy...
reading image\bmp.ksy...
... compiling it for javascript...
.... writing Bmp.js

It's possible that the yaml.js is not strictly compliant to the YAML spec, so the document is not parsed properly, but that's not the thing I wanted to show. It looks like quoting the string using quotes is the only way to make it compile under JVM, because in fact all other variants of YAML multiline syntax are rejected:

1. literal style (| - "Keep newlines (literal)" at https://yaml-multiline.info/)

           type: |
             color_table(
               not header.is_core_header,
               header.extends_bitmap_info ? header.bitmap_info_ext.num_colors_used : 0
             )

   $ ksc --debug -t javascript --verbose file -I . image/bmp.ksy
   parsing image\bmp.ksy...
   reading image\bmp.ksy...
   /types/bitmap_info/seq/3: unable to find type 'color_table(
     not header.is_core_header,
     header.extends_bitmap_info ? header.bitmap_info_ext.num_colors_used : 0
   )
   ', searching from bmp
   

2. folded style with strip chomping indicator (>- - "Replace newlines with spaces (folded)" with "No newline at end (strip)" at https://yaml-multiline.info/)

           type: >-
             color_table(
               not header.is_core_header,
               header.extends_bitmap_info ? header.bitmap_info_ext.num_colors_used : 0
             )

   $ ksc --debug -t javascript --verbose file -I . image/bmp.ksy
   parsing image\bmp.ksy...
   reading image\bmp.ksy...
   /types/bitmap_info/seq/3: unable to find type 'color_table(
     not header.is_core_header,
     header.extends_bitmap_info ? header.bitmap_info_ext.num_colors_used : 0
   )', searching from bmp
   

So I think it totally makes sense to tolerate the whitespace.

[generalmimon]

BTW, a similar issue has been addressed by kaitai-io/kaitai_struct_compiler#133.