More 6502 assembly parser work.

src/MOS/6502/assembler/parser.js

@@ -25,6 +25,10 @@ function TokenStream(input){
     return (pos < input.length) ? input[pos].col : -1;
   }
 
+  function eol(){
+    return (pos < input.length - 1) ? (input[pos].line !== input[pos+1].line) : true;
+  }
+
   function eof(){
     return (pos >= input.length);
   }
@@ -54,7 +58,7 @@ function isTokenType(type, val){
 }
 
 function isPunc(ch){
-  return isTokenType("punk", ch);
+  return isTokenType("punc", ch);
 }
 
 function isOpCode(ch){
@@ -74,6 +78,63 @@ function isOp(ch){
 }
 
 
+function skipPunc(ch){
+  if (isPunc(ch)){
+    stream.next();
+  } else {
+    stream.die("Unexpected punctuation '" + ch + "'.");
+  }
+}
+
+
+parseDelimited(s,e,d,parser){
+  let toEOL = (s === null || e === null);
+  let a = [];
+  let first = true;
+  if (!toEOL){skipPunc(s);}
+  while (!stream.eof() && ((!toEOL && isPunc(e)) || (toEOL && !stream.eol()))){
+    if (first){
+      first = false;
+    } else {skipPunk(d);}
+    a.push(parser());
+  }
+  if (!toEOL){skipPunc(e);}
+  return a;
+}
+
+
+parseOpCode(){
+  let val = stream.next();
+  let mode = 0; // Guess between absolute and zero page.
+  let args = []; // TODO: Finish figuring out how to get the argument list!
+  if (isOp("#")){
+    stream.next();
+    mode = 1; // Immediate
+  } else if (isPunc("(")){
+    mode = 2; // Indirect
+    // TODO: Use parseDelimited()
+  }
+  return {
+    type: "opcode",
+    val: val,
+    args: args,
+    mode: mode
+  };
+}
+
+parseAtom(){
+  if (isPunc("(")){
+    stream.next();
+    let exp = parseExpression();
+    if (isPunc(")")){
+      stream.next();
+      return exp;
+    }
+  } else if (isOpCode()){
+    return parseOpCode();
+  }
+}
+
 
 parse(tokens){
   let p = {