@external propSource highlighting from "./highlight.js"
@top Program { (Expression newline)* }

@tokens {  
  Number { "-"? $[0-9]+ ('.' $[0-9]+)? }
  Boolean { "true" | "false" }
  String { '\'' !["]* '\'' }
  newline { "\n" | @eof }
  space { " " }
  leftParen { "(" }
  rightParen { ")" }
  "+"[@name=operator]
  "-"[@name=operator]
  "*"[@name=operator]
  "/"[@name=operator]  
}

@external tokens tokenizer from "./tokenizers" { Identifier, Word }
@precedence {   
  multiplicative @left,
  additive @left
}

Expression {
  FunctionCall |
  FunctionCallOrIdentifier |
  BinOp |
  ParenExpr | 
  Word | 
  String | 
  Number | 
  Boolean
}


FunctionCallOrIdentifier { 
  Identifier
}

FunctionCall {
  Identifier (~ambig space arg)+
}

arg {
  PositionalArg | NamedArg | IncompleteNamedArg
}

PositionalArg {
  value
}

NamedArg {
  Identifier "=" value
}

IncompleteNamedArg {
  Identifier "="
}

BinOp {
  operand ~ambig space !multiplicative "*" space operand |
  operand ~ambig space !multiplicative "/" space operand |
  operand ~ambig space !additive "+" space operand |
  operand ~ambig space !additive "-" space operand
}

operand {
  value | BinOp
}


ParenExpr {
  leftParen Expression rightParen
}

value {
  ParenExpr | Identifier | Word | String | Number | Boolean
}