`-webide-representation` doesn't work for arrays of primitive values

[matthewturk]

I'm trying to use -webide-representation to display the values of a parameterized type. My guess is that it isn't supported, but I was kind of hoping there might be a way to make it work -- it's similar but not identical to the example using MACH-O on the website. My type definition is:

  fortran_record:
    params:
      - id: num_records
        type: u4
      - id: record_type
        type: str
    seq:
      - id: rec_size1
        type: u4
      - id: value
        type:
          switch-on: record_type
          cases:
            '"u4"': u4
            '"u8"': u8
            '"f4"': f4
            '"f8"': f8
        repeat: expr
        repeat-expr: num_records
      - id: rec_size2
        type: u4
    -webide-representation: "{value}"

When it parses, it throws this error:

Parse error (TypeError): Cannot read properties of undefined (reading 'ksyType')
Call stack: TypeError: Cannot read properties of undefined (reading 'ksyType')
    at ParsedTreeHandler.reprObject (https://ide.kaitai.io/js/v1/parsedToTree.js:81:35)
    at https://ide.kaitai.io/js/v1/parsedToTree.js:119:65
    at Array.map (<anonymous>)
    at https://ide.kaitai.io/js/v1/parsedToTree.js:119:48
    at [Symbol.replace] (<anonymous>)
    at String.replace (<anonymous>)
    at ParsedTreeHandler.reprObject (https://ide.kaitai.io/js/v1/parsedToTree.js:85:45)
    at ParsedTreeHandler.childItemToNode (https://ide.kaitai.io/js/v1/parsedToTree.js:145:33)
    at https://ide.kaitai.io/js/v1/parsedToTree.js:189:70
    at Array.map (<anonymous>)
    at ParsedTreeHandler.exportedToNodes (https://ide.kaitai.io/js/v1/parsedToTree.js:189:48)
    at https://ide.kaitai.io/js/v1/parsedToTree.js:267:34

My assumption is that the representation generation is being called before the type gets added as a property on the object by the switch statement, but perhaps that's wrong. I've tried a few different things, like using {value[0]} and whatnot, but it didn't quite work. Any ideas, or will this just require efforts along the same lines as kaitai-io/kaitai_struct#1073 ? Thanks!

[generalmimon]

Turns out -webide-representation currently supports only user type arrays, not primitive type arrays. This works:

seq:
  - id: foo
    type: arr
types:
  arr:
    -webide-representation: '{items}'
    seq:
      - id: items
        type: item
        repeat: expr
        repeat-expr: 3
  item:
    -webide-representation: '{value:dec}'
    seq:
      - id: value
        type: s1

But once we replace type: item with type: s1, we get the error that you mentioned before:

seq:
  - id: foo
    type: arr
types:
  arr:
    -webide-representation: '{items}'
    seq:
      - id: items
        type: s1
        repeat: expr
        repeat-expr: 3

Parse error (TypeError): Cannot read properties of undefined (reading 'ksyType')

So if wrapping the item type to user-defined type is acceptable for you, it seems to work around the problem.

[matthewturk]

Thank you, this works for me! Happy to have the issue closed if appropriate.

[generalmimon]

Happy to have the issue closed if appropriate.

Let's keep this issue open as a reminder that the problem exists.