Make the scanner comment-aware so <% # ... : %> works as expected. F…

…ixes sstephenson#18.

lib/scanner.js

@@ -4,8 +4,9 @@
   trim = require("./util").trim;
   module.exports = Scanner = (function() {
     Scanner.modePatterns = {
-      data: /(.*?)(<%%|<%(([=-])?)|\n|$)/,
-      code: /(.*?)(((:|(->|=>))\s*)?%>|\n|$)/
+      data: /(.*?)(<%%|<%\s*(\#)|<%(([=-])?)|\n|$)/,
+      code: /(.*?)((((:|(->|=>))\s*))?%>|\n|$)/,
+      comment: /(.*?)(%>|\n|$)/
     };
     Scanner.dedentablePattern = /^(end|when|else|catch|finally)(?:\W|$)/;
     Scanner.scan = function(source) {
@@ -45,15 +46,18 @@
             return this.scanData(callback);
           case "code":
             return this.scanCode(callback);
+          case "comment":
+            return this.scanComment(callback);
         }
       }
     };
     Scanner.prototype.advance = function() {
       this.scanner.scanUntil(Scanner.modePatterns[this.mode]);
       this.buffer += this.scanner.getCapture(0);
       this.tail = this.scanner.getCapture(1);
-      this.directive = this.scanner.getCapture(3);
-      return this.arrow = this.scanner.getCapture(4);
+      this.comment = this.scanner.getCapture(2);
+      this.directive = this.scanner.getCapture(4);
+      return this.arrow = this.scanner.getCapture(5);
     };
     Scanner.prototype.scanData = function(callback) {
       if (this.tail === "<%%") {
@@ -64,14 +68,18 @@
         this.lineNo++;
         return this.scan(callback);
       } else if (this.tail) {
-        this.mode = "code";
         callback(["printString", this.flush()]);
-        return callback([
-          "beginCode", {
-            print: this.directive != null,
-            safe: this.directive === "-"
-          }
-        ]);
+        if (this.comment) {
+          return this.mode = "comment";
+        } else {
+          this.mode = "code";
+          return callback([
+            "beginCode", {
+              print: this.directive != null,
+              safe: this.directive === "-"
+            }
+          ]);
+        }
       }
     };
     Scanner.prototype.scanCode = function(callback) {
@@ -93,6 +101,14 @@
         }
       }
     };
+    Scanner.prototype.scanComment = function(callback) {
+      if (this.tail === "\n") {
+        return callback(["fail", "unexpected newline in code block"]);
+      } else if (this.tail) {
+        this.mode = "data";
+        return this.buffer = "";
+      }
+    };
     Scanner.prototype.flush = function() {
       var buffer;
       buffer = this.buffer;

src/scanner.coffee

@@ -2,10 +2,10 @@
 {trim}          = require "./util"
 
 module.exports = class Scanner
-  @modePatterns: {
-    data: /(.*?)(<%%|<%(([=-])?)|\n|$)/
-    code: /(.*?)(((:|(->|=>))\s*)?%>|\n|$)/
-  }
+  @modePatterns:
+    data:    /(.*?)(<%%|<%\s*(\#)|<%(([=-])?)|\n|$)/
+    code:    /(.*?)((((:|(->|=>))\s*))?%>|\n|$)/
+    comment: /(.*?)(%>|\n|$)/
 
   @dedentablePattern: /^(end|when|else|catch|finally)(?:\W|$)/
 
@@ -43,13 +43,16 @@ module.exports = class Scanner
           @scanData callback
         when "code"
           @scanCode callback
+        when "comment"
+          @scanComment callback
 
   advance: ->
     @scanner.scanUntil Scanner.modePatterns[@mode]
     @buffer   += @scanner.getCapture 0
     @tail      = @scanner.getCapture 1
-    @directive = @scanner.getCapture 3
-    @arrow     = @scanner.getCapture 4
+    @comment   = @scanner.getCapture 2
+    @directive = @scanner.getCapture 4
+    @arrow     = @scanner.getCapture 5
 
   scanData: (callback) ->
     if @tail is "<%%"
@@ -62,9 +65,12 @@ module.exports = class Scanner
       @scan callback
 
     else if @tail
-      @mode = "code"
       callback ["printString", @flush()]
-      callback ["beginCode", print: @directive?, safe: @directive is "-"]
+      if @comment
+        @mode = "comment"
+      else
+        @mode = "code"
+        callback ["beginCode", print: @directive?, safe: @directive is "-"]
 
   scanCode: (callback) ->
     if @tail is "\n"
@@ -79,6 +85,14 @@ module.exports = class Scanner
       callback ["recordCode", code]
       callback ["indent", @arrow] if @directive
 
+  scanComment: (callback) ->
+    if @tail is "\n"
+      callback ["fail", "unexpected newline in code block"]
+
+    else if @tail
+      @mode   = "data"
+      @buffer = ""
+
   flush: ->
     buffer  = @buffer
     @buffer = ""

test/test_scanner.coffee

@@ -90,3 +90,14 @@ module.exports =
     test.same ["fail", "unexpected end of template"], tokens.shift()
     test.done()
 
+  "comments are ignored": (test) ->
+    tokens = scan "foo\n<%# bar %>\nbaz"
+    test.same ["printString", "foo\n"], tokens.shift()
+    test.same ["printString", "\nbaz"], tokens.shift()
+    test.done()
+
+  "a comment tag can end with a colon": (test) ->
+    tokens = scan "foo\n<% # This is a comment: %>\nbar"
+    test.same ["printString", "foo\n"], tokens.shift()
+    test.same ["printString", "\nbar"], tokens.shift()
+    test.done()