Bytes causing parse errors

I’m having issues with working with the Bytes sort. I get parse errors when using Bytes that I don’t get when using a regular Int, for example.

Minimal working example:

require "domains.k"

module BYTES-ISSUE
  imports DOMAINS
  imports BYTES

    syntax Map ::= Map "[" Int ":=" Bytes "]" [function]
 // ----------------------------------------------------
    rule BM[ N := nilBytes ] => BM
    rule BM[ N := (B : BS) ] => (BM[N <- B])[N +Int 1 := BS]
endmodule

This gives output:

kompile bytes-issue.k
[Error] Compiler: Had 2 parsing errors.
[Error] Inner Parser: Parse error: unexpected token ':'.
	Source(/home/hjort/code/wasm/k-demos/bad_error_msg/./no-square-bracket.k)
	Location(10,22,10,23)
[Error] Inner Parser: Parse error: unexpected token ']'.
	Source(/home/hjort/code/wasm/k-demos/bad_error_msg/./no-square-bracket.k)
	Location(9,28,9,29)
[Warning] Compiler: Could not find main syntax module with name ...

The problem persists when I remove one of the rules (although one parse error then goes away, of course), and if I change the square brackets to parentheses, and the := to something like <-.

The problem goes away if I change to using some other sort, like by defining Ints:

require "domains.k"

module BYTES-ISSUE
  imports DOMAINS
  imports BYTES

    syntax Ints ::= ".Ints" | Int ":" Ints      // Added line
    syntax Map  ::= Map "[" Int ":=" Ints "]"   // Bytes => Ints
 // -----------------------------------------
    rule BM[ N := .Ints ] => BM                 // nilBytes => Ints
    rule BM[ N := (B : BS) ] => (BM[N <- B])[N +Int 1 := BS]
endmodule

The problem also goes away for the first rule if I change from using nilBytes to .Bytes, which I find strange.

[dwightguth]

One feature we may consider adding to k is explicitly annotating the syntax exported by a module, but nothing like this has been created yet.

[dwightguth]

The productions in the BYTES-IN-K module are not a part of the public interface of the Bytes type and will not work in the ocaml or llvm backends. If you want to use the BYTES module, you should only rely on the functions in the BYTES-HOOKED module. If you just want a cons list, I’d recommend implementing it yourself, but note that the BYTES sort is memory efficient and has constant time update and lookup, which cannot be said of a cons list of ints.