Support backslash based escaping for placeholders

README.md

@@ -313,7 +313,12 @@ var message = "Welcome, $1";
 $.i18n(message, 'Alice'); // This gives "Welcome, Alice"
 ```
 
-
+To escape the $ sign, use double blackslash in json file. Example:
+```javascript
+{
+	"messageKey": "Price of {{PLURAL:$1|an item|$1 items}} is $2, you get \\$2 discount."
+}
+```
 ## Plurals
 
 To make the syntax of sentence correct, plural forms are required. jquery.i18n support plural forms in the message using the syntax `{{PLURAL:$1|pluralform1|pluralform2|...}}`

src/jquery.i18n.js

@@ -142,7 +142,7 @@
 				source = 'i18n/' + $.i18n().locale + '.json';
 				locale = $.i18n().locale;
 			}
-			if ( typeof source === 'string'	&&
+			if ( typeof source === 'string' &&
 				source.split( '.' ).pop() !== 'json'
 			) {
 				// Load specified locale then check for fallbacks when directory is specified in load()
@@ -260,16 +260,22 @@
 	$.i18n.parser = {
 		// The default parser only handles variable substitution
 		parse: function ( message, parameters ) {
-			return message.replace( /\$(\d+)/g, function ( str, match ) {
-				var index = parseInt( match, 10 ) - 1;
-				return parameters[ index ] !== undefined ? parameters[ index ] : '$' + match;
+			return message.replace( /(\\?\$\d+)/g, function ( str, match ) {
+				var index;
+
+				if ( match[ 0 ] === '\\' ) {
+					// Escaped.
+					return match.slice( 1 );
+				}
+				index = parseInt( match.slice( 1 ), 10 ) - 1;
+				return parameters[ index ] !== undefined ? parameters[ index ] : match;
 			} );
 		},
 		emitter: {}
 	};
 	$.i18n.fallbacks = {};
 	$.i18n.debug = false;
-	$.i18n.log = function ( /* arguments */ ) {
+	$.i18n.log = function () {
 		if ( window.console && $.i18n.debug ) {
 			window.console.log.apply( window.console, arguments );
 		}

src/jquery.i18n.parser.js

@@ -27,10 +27,15 @@
 		constructor: MessageParser,
 
 		simpleParse: function ( message, parameters ) {
-			return message.replace( /\$(\d+)/g, function ( str, match ) {
-				var index = parseInt( match, 10 ) - 1;
+			return message.replace( /(\\?\$\d+)/g, function ( str, match ) {
+				var index;
 
-				return parameters[ index ] !== undefined ? parameters[ index ] : '$' + match;
+				if ( match[ 0 ] === '\\' ) {
+					// Escaped.
+					return match.slice( 1 );
+				}
+				index = parseInt( match.slice( 1 ), 10 ) - 1;
+				return parameters[ index ] !== undefined ? parameters[ index ] : match;
 			} );
 		},
 

test/i18n/test-en.json

@@ -1,5 +1,6 @@
 {
 	"message_1": "ONE",
 	"message_2": "TWO",
-	"message_3": "THREE"
+	"message_3": "THREE",
+	"message_4": "Total \\$1 of \\$1500"
 }

test/jquery.i18n.test.js

@@ -34,7 +34,7 @@
 		}
 	} );
 
-	QUnit.test( 'Message parse tests (en)', 14, function ( assert ) {
+	QUnit.test( 'Message parse tests (en)', 16, function ( assert ) {
 		var pluralAndGenderMessage,
 			pluralAndGenderMessageWithLessParaMS,
 			pluralAndGenderMessageWithCase,
@@ -49,13 +49,18 @@
 			QUnit.start();
 			assert.strictEqual( i18n.locale, 'en', 'Locale is English' );
 			assert.strictEqual( $.i18n( 'message_1' ), 'ONE', 'Simple message' );
+			assert.strictEqual( $.i18n( 'message_4', 5 ), 'Total $1 of $1500', 'Parameter replacement escaped' );
 		} );
 		assert.strictEqual(
 			$.i18n( 'This message key does not exist' ),
 			'This message key does not exist',
 			'This message key does not exist'
 		);
 		assert.strictEqual( $.i18n( 'Hello $1', 'Bob' ), 'Hello Bob', 'Parameter replacement' );
+		assert.strictEqual(
+			$.i18n( 'Price of {{PLURAL:$1|an item|$1 items}} is $2, you get \\$2 discount', 5, 2000 ),
+			'Price of 5 items is 2000, you get $2 discount', 'Parameter replacement with dollar sign escaped, not parsed using simplePaser'
+		);
 		pluralAndGenderMessage = '$1 has $2 {{plural:$2|kitten|kittens}}. ' +
 			'{{gender:$3|He|She}} loves to play with {{plural:$2|it|them}}.';
 		pluralAndGenderMessageWithLessParaMS = '$1 has $2 {{plural:$2|kitten}}. ' +