generator: add keyword method, remove __ident method and implement better position tracking

lib/6to5/generator.js

@@ -20,6 +20,9 @@ function CodeGenerator(code, ast, opts) {
   this.ast      = ast;
   this.buf      = "";
 
+  this.line   = 1;
+  this.column = 0;
+
   if (opts.sourceMap) {
     this.map = new sourceMap.SourceMapGenerator({
       file: opts.sourceMapName
@@ -38,16 +41,11 @@ CodeGenerator.prototype.mark = function (node, locType) {
   var map = this.map;
   if (!map) return; // no source map
 
-  var lines = this.buf.split("\n");
-
-  var line = lines.length;
-  var col  = _.last(lines).length;
-
   map.addMapping({
     source: this.opts.sourceFileName,
     generated: {
-      line: line,
-      column: col
+      line: this.line,
+      column: this.column
     },
     original: loc[locType]
   });
@@ -55,10 +53,12 @@ CodeGenerator.prototype.mark = function (node, locType) {
 
 CodeGenerator.prototype.newline = function () {
   this.buf += "\n";
+  this.line++;
 };
 
 CodeGenerator.prototype.semicolon = function () {
   this.buf += ";";
+  this.column++;
 };
 
 CodeGenerator.prototype.push = function (str) {
@@ -73,6 +73,17 @@ CodeGenerator.prototype.push = function (str) {
     if (_.last(this.buf) === "\n") str = indent + str;
   }
 
+  var self = this;
+
+  _.each(str, function (cha) {
+    if (cha === "\n") {
+      self.line++;
+      self.column = 0;
+    } else {
+      self.column++;
+    }
+  });
+
   this.buf += str;
 };
 
@@ -88,12 +99,6 @@ CodeGenerator.prototype.dedent = function () {
   this._indent--;
 };
 
-CodeGenerator.prototype.__indent = function (str) {
-  return str.split("\n").map(function (line) {
-    return "  " + line;
-  }).join("\n");
-};
-
 CodeGenerator.prototype.generate = function () {
   var ast = this.ast;
 
@@ -142,6 +147,11 @@ CodeGenerator.prototype.print = function (node, parent) {
   }
 };
 
+CodeGenerator.prototype.keyword = function (name) {
+  this.push(name);
+  this.push(" ");
+};
+
 CodeGenerator.prototype.generateComment = function (comment) {
   var val = comment.value;
   if (comment.type === "Line") {