@preprocessor typescript

@{%
import { Expr } from "./parsed";
%}

expr -> term {% id %}

term -> term "+" factor
		{% ([left, _, right]): Expr =>
			({ exprType: "binary", binaryType: "add", left, right }) %}
	| term "-" factor
		{% ([left, _, right]): Expr =>
			({ exprType: "binary", binaryType: "subtract", left, right }) %}
	| factor {% id %}

factor -> factor "*" unary
		{% ([left, _, right]): Expr =>
			({ exprType: "binary", binaryType: "multiply", left, right }) %}
	| factor "/" unary
		{% ([left, _, right]): Expr =>
			({ exprType: "binary", binaryType: "divide", left, right }) %}
	| unary {% id %}

unary -> "+" unary
		{% ([_, subject]): Expr =>
			({ exprType: "unary", unaryType: "plus", subject }) %}
	| "-" unary
		{% ([_, subject]): Expr =>
			({ exprType: "unary", unaryType: "negate", subject }) %}
	| operand {% id %}

operand -> "(" expr ")" {% ([_, expr]): Expr => expr %}
	| ("0" | [1-9][0-9]:*) {% ([token]): Expr => ({ exprType: "int", value: parseInt(token.value) }) %}

_ -> __:?
__ -> [ \t\r\n]:+