User:Zocky

{ function OP(h,t,opc,valc) {

   	if (!t.length) return h;
   	opc = opc || 1;
       valc = valc || 3;
       var ret =  [h];
       t.forEach(function(n) {
       	ret.push(n[opc]);
       	ret.push(n[valc]);
       })
       return ret;
   }
   function EVAL(nodes,ctx) {
       if (!Array.isArray(nodes)) return nodes;
   	var acc = EVAL(nodes[0],ctx);
       for (var i = 1; i<nodes.length;) {
       	var op = nodes[i++];
           console.log(acc,op);
           switch (op) {
           case '+': acc+=EVAL(nodes[i++],ctx); break;
           case '-': acc-=EVAL(nodes[i++],ctx); break;
           case '*': acc*=EVAL(nodes[i++],ctx); break;
           case '/': acc/=EVAL(nodes[i++],ctx); break;
           case '%': acc%=EVAL(nodes[i++],ctx); break;
           case '$': acc=ctx[acc]; break;
           case '=': acc = ctx[acc] = EVAL(nodes[i++],ctx);; break;
           case ';':
           case ',': acc=EVAL(nodes[i++],ctx); break;
           	
           }
       }
       return acc;
   }

} program = e:statements { return [EVAL(e,{a:3}),!e];} statements = h:statement t:(_ ';' _ statement)* ';'? { return OP(h,t)} statement = assign/expr assign = n:ident _ "=" _ e:expr { return [n,'=',e] } expr = addsub addsub = h:muldiv t:( _ [+-] _ muldiv)* { return OP(h,t)} muldiv = h:atom t:( _ [*/%] _ atom)* { return OP(h,t)} atom = path/number/brackets brackets = _ "(" _ e:expr _ ")" _ { return e} path = h:head t:( _ [.] _ key)* { return OP(h,t)} head = i:ident { return [i,'$']; }/brackets key = ident/digits/brackets number = n:$( d:digits ('.' digits)? ([Ee] digits)?) { return Number(n);} digits = [0-9]+ ident = $([A-Z_]i [A-Z0-9_]i*) _ = [ \n\r\t]* __ = [ \n\r\t]+