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start = numberedLine / statement

lineNumber = digits:[0-9]+ { return parseInt(digits.join(""), 10); }

numberedLine = numb:lineNumber [ ]+ stat:statement { return [numb,stat]; }

integerNumber = sign:"-"? digits:[0-9]+
{
	var val=parseInt(digits.join(""), 10);

if (sign=="-")
	{
		return -val; 
	}
	
	return val;
}

floatNumber = sign:"-"? idigits:[0-9]+ "." fdigits:[0-9]+
{
	var val=0;
	var ival=parseInt(idigits.join(""), 10);
	var fval=fdigits.join("");
	
	var concat=ival.toString()+"."+fval.toString();
		
	val=parseFloat(concat);

if (sign=="-")
	{
		return -val; 
	}
	
	return val;
}

statement = printStmt / 
						returnStmt / 
						listStmt / 
						runStmt /
						clearStmt /
						gotoStmt / 
						inputStmt /
						endStmt /
						helpStmt /
						remStmt /
						verStmt /
						letStmt /
						forStmt /
						nextStmt /
						ifStmt / 
						inputStmt / 
						gosubStmt /
						returnStmt /
						loadStmt /
						dirStmt /
						saveStmt / 
						plotStmt /
						readStmt /
						dataStmt / 
						restoreStmt
						
printStmt = "print"i ([ ])* prtarg:(expression)* 
{ 
	if (prtarg.length>0)
	{
		return ["print",prtarg]; 
	}
	else return ["print"];	
}

quotedString = ('"' strg:[a-zA-Z0-9 \#\.\,\*\$\;\:\'\`\|\[\]\/\+\-\\\@\=\_\~\?\*\!]* '"') { return "'"+strg.join("")+"'"; }

charLiteral = ("'" strg:[a-zA-Z0-9 \.\,\*\$\;\:\?\*\!\|\\\/\-]* "'") { return "'"+strg.join("")+"'"; }

variable = the1var:[a-zA-Z] the2var:[a-zA-Z0-9\$]* { return the1var+the2var.join(""); }

readStmt = "read"i [ ]+ head:variable tail:("," variable)*
{
	var varArray=new Array();
	
	varArray.push(head);
	
	for (var i = 0; i < tail.length; i++) 
	{        
		varArray.push(tail[i][1]);
	}

return ["read",varArray];
}

dataStmt = "data"i [ ]+ head:dataData tail:("," dataData)*
{
	var dataArray=new Array();
	
	dataArray.push(head);
	
	for (var i = 0; i < tail.length; i++) 
	{        
		dataArray.push(tail[i][1]);
	}

return ["data",dataArray];
}

restoreStmt = "restore"i { return ["restore"]; }

dataData = floatNumber / integerNumber / quotedString

functionCall = "rnd"i "(" maxr:expression ")" { return { tag: "rnd", imax: maxr }; } /
							 "chr$"i "(" asciicode:expression ")" { return { tag: "chr$", ascii: asciicode }; } /
							 "sin"i "(" operand:expression ")" { return { tag: "sin",opz:operand }; } /
							 "cos"i "(" operand:expression ")" { return { tag: "cos",opz:operand }; } /
							 "int"i "(" operand:expression ")" { return { tag: "int",opz:operand }; }

/* mathematical expression */

additiveOperator = "+" { return "+"; } / "-" { return "-"; }

multiplicativeOperator = "*" { return "*"; } / "/" { return "/"; }

expression = additive

additive = head:multiplicative tail:(additiveOperator multiplicative)* 
{      
	var result = head;      
	for (var i = 0; i < tail.length; i++) 
	{        
		result = 
		{          
			tag: 			tail[i][0],          
			left:     result,          
			right:    tail[i][1]        
		};      
	}      
	return result;    
}

multiplicative = head:primary tail:(multiplicativeOperator primary)* 
{      
	var result = head;      
	for (var i = 0; i < tail.length; i++) 
	{        
		result = 
		{          
			tag: 			tail[i][0],          
			left:     result,          
			right:    tail[i][1]        
		};      
	}      
	return result;    
}

primary = floatNumber /
					integerNumber / 
					quotedString /
					functionCall /
					variable /
					charLiteral /
					"(" additive:additive ")" { return additive; }
					
/* other statements */

plotStmt = "plot"i [ ]+ thechar:expression [,] posx:expression [,] posy:expression { return ["plot",thechar,posx,posy]; }

dirStmt = "directory"i { return ["directory"]; } / "dir"i { return ["directory"]; }

loadStmt = "load"i [ ]+ progname:quotedString { return ["load",progname]; }

saveStmt = "save"i [ ]+ progname:quotedString { return ["save",progname]; }

ifStmt = "if"i [ ]+ lexpr:expression [ ]* rop:relop [ ]* rexpr:expression [ ]+ "then"i [ ]+ stat:statement 
				 { return ["if",lexpr,rop,rexpr,stat]; }

relop = "<=" / ">=" / "<" / ">" / "="

inputStmt = "input"i [ ]+ avar:variable {return ["input",avar]; }

gosubStmt = "gosub"i [ ]+ anum:lineNumber { return ["gosub",anum]; }

returnStmt = "return"i { return ["return"]; }

forStmt = "for"i [ ]+ avar:variable [=] exprfrom:expression [ ]+ "to"i [ ]+ exprto:expression
					{ return ["for",avar,exprfrom,exprto]; }

nextStmt = "next"i [ ]+ avar:variable { return ["next",avar]; }

letStmt = "let"i [ ]+ avar:variable [=] expr:expression { return ["let",avar,expr]; }

remStmt = "rem"i [^]* {return ["rem"]; }

inputStmt = "input"i [ ]+ avar:variable { return ["input",avar]; }

gotoStmt = "goto"i [ ]+ anum:lineNumber { return ["goto",anum]; }

endStmt = "end"i { return ["end"]; }

returnStmt = "return"i { return ["return"]; }

listStmt = "list"i { return ["list"]; }

runStmt = "run"i { return ["run"]; }

clearStmt = "cls"i { return ["cls"]; }

helpStmt = "help"i { return ["help"]; }

verStmt = "version"i { return ["version"]; }