clean up lib/parse.js (#2047)

- remove unused definitions
- replace `array_to_hash()`

lib/parse.js

@@ -115,8 +115,6 @@ var PUNC_BEFORE_EXPRESSION = makePredicate(characters("[{(,;:"));
 
 var PUNC_CHARS = makePredicate(characters("[]{}(),;:"));
 
-var REGEXP_MODIFIERS = makePredicate(characters("gmsiy"));
-
 /* -----[ Tokenizer ]----- */
 
 // regexps adapted from http://xregexp.com/plugins/#unicode
@@ -684,9 +682,7 @@ var PRECEDENCE = (function(a, ret){
     {}
 );
 
-var STATEMENTS_WITH_LABELS = array_to_hash([ "for", "do", "while", "switch" ]);
-
-var ATOMIC_START_TOKEN = array_to_hash([ "atom", "num", "string", "regexp", "name" ]);
+var ATOMIC_START_TOKEN = makePredicate([ "atom", "num", "string", "regexp", "name" ]);
 
 /* -----[ Parser ]----- */
 
@@ -1222,7 +1218,6 @@ function parse($TEXT, options) {
         var tok = S.token, ret;
         switch (tok.type) {
           case "name":
-          case "keyword":
             ret = _make_symbol(AST_SymbolRef);
             break;
           case "num":
@@ -1252,13 +1247,6 @@ function parse($TEXT, options) {
                 break;
             }
             break;
-          case "operator":
-            if (!is_identifier_string(tok.value)) {
-                croak("Invalid getter/setter name: " + tok.value,
-                    tok.line, tok.col, tok.pos);
-            }
-            ret = _make_symbol(AST_SymbolRef);
-            break;
         }
         next();
         return ret;
@@ -1292,7 +1280,7 @@ function parse($TEXT, options) {
             func.end = prev();
             return subscripts(func, allow_calls);
         }
-        if (ATOMIC_START_TOKEN[S.token.type]) {
+        if (ATOMIC_START_TOKEN(S.token.type)) {
             return subscripts(as_atom_node(), allow_calls);
         }
         unexpected();