Initial bits for parser

src/ol/expression/expression.js

@@ -0,0 +1,112 @@
+/**
+ * Support a very limited subset of ECMAScript 5.1
+ * http://www.ecma-international.org/ecma-262/5.1/
+ *
+ * Inspired by Esprima (https://github.com/ariya/esprima)
+ * BSD Licensed
+ */
+
+
+/**
+ * @enum {string}
+ */
+ol.expression.Syntax = {
+  BinaryExpression: 'BinaryExpression',
+  CallExpression: 'CallExpression',
+  Identifier: 'Identifier',
+  Literal: 'Literal',
+  LogicalExpression: 'LogicalExpression',
+  MemberExpression: 'MemberExpression',
+  Property: 'Property', // dot notation only
+  UnaryExpression: 'UnaryExpression' // only with logical not
+};
+
+
+/**
+ * @enum {string}
+ */
+ol.expression.Token = {
+  BooleanLiteral: 'Boolean',
+  EOF: '<end>',
+  Identifier: 'Identifier',
+  Keyword: 'Keyword',
+  NullLiteral: 'Null',
+  NumericLiteral: 'Numeric',
+  Punctuator: 'Punctuator',
+  StringLiteral: 'String'
+};
+
+
+/**
+ * http://www.ecma-international.org/ecma-262/5.1/#sec-7.2
+ * @param {number} ch The unicode of a character.
+ * @return {boolean} The character is whitespace.
+ */
+ol.expression.isWhitespace = function(ch) {
+  return (ch === 32) || // <SP>
+      (ch === 9) || // <TAB>
+      (ch === 0xB) || // <VT>
+      (ch === 0xC) || // <FF>
+      (ch === 0xA0) || // <NBSP>
+      (ch >= 0x1680 && '\u1680\u180E\u2000\u2001\u2002\u2003\u2004\u2005' +
+          '\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000\uFEFF'
+          .indexOf(String.fromCharCode(ch)) > 0);
+};
+
+
+/**
+ * http://www.ecma-international.org/ecma-262/5.1/#sec-7.3
+ * @param {number} ch The unicode of a character.
+ * @return {boolean} The character is a line terminator.
+ */
+ol.expression.isLineTerminator = function(ch) {
+  return (ch === 10) || // <LF>
+      (ch === 13) || // <CR>
+      (ch === 0x2028) || // <LS>
+      (ch === 0x2029); // <PS>
+};
+
+
+/**
+ * http://www.ecma-international.org/ecma-262/5.1/#sec-7.6
+ * Doesn't deal with non-ascii identifiers.
+ * @param {number} ch The unicode of a character.
+ * @return {boolean} The character is a valid identifier start.
+ */
+ol.expression.isIdentifierStart = function(ch) {
+  return (ch === 36) || (ch === 95) || // $ (dollar) and _ (underscore)
+      (ch >= 65 && ch <= 90) ||        // A..Z
+      (ch >= 97 && ch <= 122);         // a..z
+};
+
+
+/**
+ * http://www.ecma-international.org/ecma-262/5.1/#sec-7.6
+ * Doesn't deal with non-ascii identifiers.
+ * @param {number} ch The unicode of a character.
+ * @return {boolean} The character is a valid identifier part.
+ */
+ol.expression.isIdentifierPart = function(ch) {
+  return ol.expression.isIdentifierStart(ch) ||
+      (ch >= 48 && ch <= 57); // 0..9
+};
+
+
+/**
+ * http://www.ecma-international.org/ecma-262/5.1/#sec-7.6.1.2
+ * @param {string} id A string identifier.
+ * @return {boolean} The identifier is a future reserved word.
+ */
+ol.expression.isFutureReservedWord = function(id) {
+  switch (id) {
+    case 'class':
+    case 'enum':
+    case 'export':
+    case 'extends':
+    case 'import':
+    case 'super':
+      return true;
+    default:
+      return false;
+  }
+};