fix for production output (generated parsers):

- added the option `-T` (`--output-debug-tables`) which you can add to the jison command line options when you wish to *keep* the (otherwise unused) `nonterminals_` table, which lists the entire grammar verbatim.

- strip the `nonterminals_` table output from the output when the above option is not set; prep code to have the table produce more / additional debug/diagnostics data when the user **does** want the table to be included in the output.

lib/jison.js

@@ -82,7 +82,7 @@ var Production = typal.construct({
         this.precedence = 0;
     },
     toString: function Production_toString() {
-        return this.symbol + ' -> ' + this.handle.join(' ');
+        return this.symbol + (this.nullable ? '~' : '') + (this.precedence ? ' @' + this.precedence : '') + ' -> ' + this.handle.join(' ');
     }
 });
 
@@ -962,7 +962,7 @@ lookaheadMixin.firstSets = function firstSets() {
         nonterminals = this.nonterminals,
         self = this,
         cont = true,
-        symbol,firsts;
+        symbol, firsts;
 
     // loop until no further changes have been made
     while (cont) {
@@ -1106,8 +1106,13 @@ lrGeneratorMixin.Item = typal.construct({
     toString: function () {
         var temp = this.production.handle.slice(0);
         temp[this.dotPosition] = '.' + (temp[this.dotPosition] || '');
-        return this.production.symbol + ' -> ' + temp.join(' ') +
-            (this.follows.length === 0 ? '' : '     #lookaheads= ' + this.follows.join(' '));
+        var s = this.production.symbol + ' -> ' + temp.join(' ');
+        var padlen = Math.max(4, 40 - s.length);
+        var pad = new Array(padlen);
+        if (this.follows.length) {
+            s = s + pad.join(' ') + '#lookaheads= ' + this.follows.join(' ');
+        }
+        return s;
     }
 });
 
@@ -2147,7 +2152,11 @@ lrGeneratorMixin.generateModule_ = function generateModule_() {
         return nt;
     }
 
-    function produceProductionsForDebugging(tbl, sym) {
+    function produceProductionsForDebugging(tbl, sym, options) {
+        if (!options.outputDebugTables) {
+            return undefined;
+        }
+
         var prods = {};
         for (var nonterm in tbl) {
             var entry = tbl[nonterm];
@@ -2156,9 +2165,9 @@ lrGeneratorMixin.generateModule_ = function generateModule_() {
             var item_tbl = entry.productions._items;
             for (var i = 0, len = item_tbl.length; i < len; i++) {
                 var p = item_tbl[i];
-                item_prods[p.id] = p.handle.map(function (t) {
+                var rulestr = p.handle.map(function (t) {
                     if (!t) {
-                        t = '<epsilon>';
+                        t = '%epsilon';
                     }
                     // `$eof` is a synonym of `$end` for bison compatibility; 
                     // this is the only place where two symbol names may map to a single symbol ID number
@@ -2169,6 +2178,11 @@ lrGeneratorMixin.generateModule_ = function generateModule_() {
                     }
                     return t;
                 }).join(' ');
+                item_prods[p.id] = {
+                    handle: rulestr,
+                    first: [0],
+                    follow: [0]
+                };
             }
             prods[nonterm] = item_prods;
         }
@@ -2196,6 +2210,7 @@ lrGeneratorMixin.generateModule_ = function generateModule_() {
           _: 1,
           noMain: 1,
           compressTables: 1,
+          outputDebugTables: 1,
           file: 1,
           outfile: 1,
           inputPath: 1,
@@ -2237,6 +2252,10 @@ lrGeneratorMixin.generateModule_ = function generateModule_() {
     if (descrLst) {
         descrLst = descrLst.replace(/"([0-9]+)":/g, '$1:');
     }
+    var rulesLst = JSON.stringify(produceProductionsForDebugging(this.nonterminals, this.symbols_, this.options), null, 2);
+    if (rulesLst) {
+        rulesLst = rulesLst.replace(/"([0-9]+)":/g, '$1:');
+    }
 
     var moduleCode = '{\n';
     moduleCode += [
@@ -2248,8 +2267,11 @@ lrGeneratorMixin.generateModule_ = function generateModule_() {
         'options: ' + produceOptions(this.options),
         'symbols_: ' + JSON.stringify(produceSymbolTable(this.symbols_), null, 2),
         'terminals_: ' + JSON.stringify(this.terminals_, null, 2).replace(/"([0-9]+)":/g, '$1:'),
-        'nonterminals_: ' + JSON.stringify(produceProductionsForDebugging(this.nonterminals, this.symbols_), null, 2).replace(/"([0-9]+)":/g, '$1:'),
     ].concat(
+        rulesLst ?
+        'nonterminals_: ' + rulesLst :
+        []
+    ).concat(
         descrLst ?
         'terminal_descriptions_: ' + descrLst :
         []