module robot

import Prelude;

keyword MyKeywords = "begin" | "end" | "if" | "while" | "else" | "do" | "repeat" ;

layout Layout = Whitespace* !>> [\ \t\n\r];
lexical Whitespace = [\ \t\n\r];

lexical Name = [a-zA-Z] !<< [a-zA-Z]+ !>> [a-zA-Z] \ MyKeywords ;
lexical Integer = [0-9] !<< [0-9]+ !>> [0-9];
lexical String = [\"] ![\"]* [\"];
lexical CommentText = ![\n]* [\n];

start syntax RobotProgram =
    program: "Script" Name scriptName "runs as"
        {Statement ""}* body
        "end";

syntax Statement =
    Command com
    | ifStatement: "if" Expression cond "do" {Statement ""}* body "end"
    | ifElseStat: "if" Expression cond "do" {Statement ""}* body "end" "else do" {Statement ""}* elsebody "end"
    | While: "while" Expression cond "do" {Statement ""}* body "end"
    | Repeat: "repeat" Integer int "times" {Statement ""}* body "end"
    | Comment: "#" CommentText body;

syntax Command =
	"step" | "turnLeft" | "drop" | "pick"
	| "trace" String message
	| "buildWall at" "row:" Integer introw "col:" Integer intcol
	| "destroyWall at" "row:" Integer introw "col:" Integer intcol
	| "dropMark at" "row:" Integer introw "col:" Integer intcol
	| "pickMark at" "row:" Integer introw "col:" Integer intcol;

syntax Expression =
	"full" | "mark" | "wall ahead" | "heading" Direction dir
	| not: "not" Expression exp
	| and: Expression exp1 "and" Expression exp2
	| or: Expression exp1 "or" Expression exp1 ;

syntax Direction = "south" | "north" | "west" | "east" ;