Parser error on one-element lists

[AJnsm]

Description

When specifying an action space with a one-element list, this results in a parser error.

Minimal open game with this behaviour:

testGame = [opengame|
   inputs    :  ;
   feedback  :  ;
   :---------------------------:
   inputs:    ;
   feedback:  ;
   operation: dependentDecision "p1" (const [1]);
   outputs: discardedOutput;
   returns: 0;
   :----------------------------:
   outputs   :  ;
   returns   :  ;
   |]

Expected behaviour

The game compiles.

Actual behaviour

Compilation raises the following error:

/open-games-hs/src/Examples/PieCutting_open.hs:171:12: error:
    • Exception when trying to run compile-time code:
        "verbose parser" (line 6, column 47):
unexpected "]"
expecting digit, "(", "if", "\\", identifier, natural, literal string, "[", "do", "let", operator, "," or ".."
CallStack (from HasCallStack):
  error, called at /open-games-hs/src/Preprocessor/Compile.hs:108:39 in main:Preprocessor.Compile
      Code: Language.Haskell.TH.Quote.quoteExp
              opengame
              "\n\
              \   inputs    :  ;\n\
              \   feedback  :  ;\n\
              \   :---------------------------:\n\
              \   inputs:    ;\n\
              \   feedback:  ;\n\
              \   operation: dependentDecision \"p1\" (const [1]);\n\
              \   outputs: discardedOutput;\n\
              \   returns: 0;\n\
              \   :----------------------------:\n\
              \   outputs   :  ;\n\
              \   returns   :  ;\n\
              \   "
    • In the quasi-quotation:
        [opengame|
   inputs    :  ;
   feedback  :  ;
   :---------------------------:
   inputs:    ;
   feedback:  ;
   operation: dependentDecision "p1" (const [1]);
   outputs: discardedOutput;
   returns: 0;
   :----------------------------:
   outputs   :  ;
   returns   :  ;
   |]
    |
171 | testGame = [opengame|
    |            ^^^^^^^^^^...
Failed, 38 modules loaded.

Current solution

Specify the game like this:

testGame = [opengame|
   inputs    :  ;
   feedback  :  ;
   :---------------------------:
   inputs:    ;
   feedback:  ;
   operation: dependentDecision "p1" (const lsOne);
   outputs: discardedOutput;
   returns: 0;
   :----------------------------:
   outputs   :  ;
   returns   :  ;
   |]
    where 
        lsOne = [1]

This compiles, but is not a very nice solution, so changing the parser to be able to deal with this would be nicer.

[AJnsm]

Update: this bug also gets triggered for action spaces with a specified resolution:

operation : dependentDecision playerName (\x -> [0, 0.1 .. x]) ;

A similar where statement as above can get around this for the time being.