Fix bug with Lexer not recognizing exponential values and values starting with dots

Shyam Seshadri · mhevery · commit 8490bb921bd0 · 2010-10-08T20:41:19.000-07:00
diff --git a/src/Parser.js b/src/Parser.js
@@ -53,6 +53,9 @@ function lex(text, parseStrings){
       tokens.push({index:index, text:ch});
       index++;
       canStartRegExp = false;
+    } else if (ch == '.' && isNumber(peek())) {
+      readNumber();
+      canStartRegExp = false;
     } else if ( ch == ':' || ch == '.' || ch == ',' || ch == ';') {
       tokens.push({index:index, text:ch});
       index++;
@@ -104,6 +107,9 @@ function lex(text, parseStrings){
            'A' <= ch && ch <= 'Z' ||
            '_' == ch || ch == '$';
   }
+  function isExpOperator(ch) {
+    return ch == '-' || ch == '+';
+  }
   function readNumber() {
     var number = "";
     var start = index;
@@ -112,7 +118,20 @@ function lex(text, parseStrings){
       if (ch == '.' || isNumber(ch)) {
         number += ch;
       } else {
-        break;
+        var peekCh = peek();
+        if (ch == 'E' && isExpOperator(peekCh)) {
+          number += ch;
+        } else if (isExpOperator(ch) &&
+            peekCh && isNumber(peekCh) &&
+            number.charAt(number.length - 1) == 'E') {
+          number += ch;
+        } else if (isExpOperator(ch) &&
+            (!peekCh || !isNumber(peekCh)) &&
+            number.charAt(number.length - 1) == 'E') {
+          throw 'Lexer found invalid exponential value "' + text + '"';
+        } else {
+          break;
+        }
       }
       index++;
     }
diff --git a/test/ParserTest.js b/test/ParserTest.js
@@ -141,6 +141,38 @@ LexerTest.prototype.testNumber = function(){
   expect(tokens[0].text).toEqual(0.5);
 };
 
+LexerTest.prototype.testNegativeNumber = function(){
+  var value = createScope().$eval("-0.5");
+  expect(value).toEqual(-0.5);
+
+  value = createScope().$eval("{a:-0.5}");
+  expect(value).toEqual({a:-0.5});
+};
+
+LexerTest.prototype.testNumberExponent = function(){
+  var tokens = lex("0.5E-10");
+  expect(tokens[0].text).toEqual(0.5E-10);
+  expect(createScope().$eval("0.5E-10")).toEqual(0.5E-10);
+
+  tokens = lex("0.5E+10");
+  expect(tokens[0].text).toEqual(0.5E+10);
+};
+
+LexerTest.prototype.testNumberExponentInvalid = function(){
+  assertThrows('Lexer found invalid exponential value "0.5E-"', function(){
+    lex("0.5E-");
+  });
+  assertThrows('Lexer found invalid exponential value "0.5E-A"', function(){
+    lex("0.5E-A");
+  });
+};
+
+LexerTest.prototype.testNumberStartingWithDot = function(){
+  var tokens = lex(".5");
+  expect(tokens[0].text).toEqual(0.5);
+};
+
+
 ParserTest = TestCase('ParserTest');
 
 ParserTest.prototype.testExpressions = function(){
