javascript 使用宏解析javascript（可以应用于任何语言）

Posted 2021-05-04

// js fiddle for macro parsing

// expands /[a-z]+/ \+ /[a-z]+/ into match expression
//works recursively
function expandPlus(string)
{
	var index = 0;
	var first = "";
	var regx = /[a-z]/;
	//find first match
	while(!regx.test(string[index])) index++;
	//gets first match
	while(regx.test(string[index])) first += string[index++];
	//skips whitepsace
	while(/\s/.test(string[index])) index++;
	//checks for plus
	if(string[index] !== '+') {  return first; }
	index++;
	//moves onto second
	while(index < string.length && /\s/.test(string[index])) index++;


	if(regx.test(string[index])) return "(" + first + " * " + expandPlus(string.slice(index)) + ")";
	else {  return first; }

}


console.log(expandPlus(" nnnnnn   + bbbbb +cccccc g"));
// (nnnnnn * (bbbbb * cccccc))