// ================================================================
// LEXER

!whitespace : ' ' | '\t' | '\n' | '\r' ;
!comment : '#'  {.} '\n' ;

_letter : 'a'-'z' | 'A'-'Z' ;
_decdig : '0'-'9' ;
_idchar : _letter | _decdig | '_' ;

non_sigil_name : _idchar { _idchar } ;
//call : 'c' 'a' 'l' 'l' ;

// ================================================================
// IMPORT

<< import "miller/dsl" >>

// ================================================================
// PARSER

// ----------------------------------------------------------------
Root
  : SubroutineCallsite
   << dsl.NewAST($0) >>
;

// ----------------------------------------------------------------
SubroutineCallsite

  : "call" SubroutineName "(" ")"
    << dsl.NewASTNodeZary(
      $1,
      dsl.NodeTypeSubroutineCallsite,
    ) >>

  | "call" SubroutineName "(" FcnArgs ")"
    // As parsed there's an intermediate node between SubroutineCallsite
    // and the children. Now we can remove it.
    //
    // Before:
    // * SubroutineCallsite "[]"
    //     * SubroutineCallsite
    //         * StringLiteral "a"
    //         * StringLiteral "b"
    //
    // After:
    // * SubroutineCallsite "[]"
    //     * StringLiteral "a"
    //     * StringLiteral "b"
    << dsl.AdoptChildren(
      dsl.NewASTNodeNestable(
        $1,
        dsl.NodeTypeSubroutineCallsite,
      ),
      $3,
    ) >>
;

// ----------------------------------------------------------------
SubroutineName : non_sigil_name;

// ----------------------------------------------------------------
FcnArgs
  : Rvalue
    << dsl.NewASTNodeUnary(
      nil,
      $0,
      dsl.NodeTypeFunctionCallsite,
    ) >>

  // Allow trailing final comma, especially for multiline statements
  | Rvalue ","
    << dsl.NewASTNodeUnary(
      nil,
      $0,
      dsl.NodeTypeFunctionCallsite,
    ) >>

  // Allow trailing final comma, especially for multiline statements
  | Rvalue "," FcnArgs
    << dsl.PrependChild(
      $2,
      $0,
    ) >>
;


// ----------------------------------------------------------------
Rvalue
  : "x" << dsl.NewASTNodeZary($0, dsl.NodeTypeStringLiteral) >>
  | "y" << dsl.NewASTNodeZary($0, dsl.NodeTypeStringLiteral) >>
  | "z" << dsl.NewASTNodeZary($0, dsl.NodeTypeStringLiteral) >>
  ;