Adding Angular and dependent packages for testing

third_party/pkg/angular/lib/core/parser/lexer.dart

+part of angular.core.parser;
+
+@NgInjectableService()
+class Lexer {
+  List<Token> call(String text) {
+    Scanner scanner = new Scanner(text);
+    List<Token> tokens = [];
+    Token token = scanner.scanToken();
+    while (token != null) {
+      tokens.add(token);
+      token = scanner.scanToken();
+    }
+    return tokens;
+  }
+}
+
+class Scanner {
+  final String input;
+  final int length;
+
+  // TODO(kasperl): Get rid of this buffer. It is currently used for
+  // pushing back tokens for method calls found while scanning
+  // identifiers. We should be able to do this in the parser instead.
+  final List<Token> buffer = [];
+
+  int peek = 0;
+  int index = -1;
+
+  Scanner(String input) : this.input = input, this.length = input.length {
+    advance();
+  }
+
+  Token scanToken() {
+    // TODO(kasperl): The current handling of method calls is somewhat
+    // complicated. We should simplify it by dealing with it in the parser.
+    if (!buffer.isEmpty) return buffer.removeLast();
+
+    // Skip whitespace.
+    while (isWhitespace(peek)) advance();
+
+    // Handle identifiers and numbers.
+    if (isIdentifierStart(peek)) return scanIdentifier();
+    if (isDigit(peek)) return scanNumber(index);
+
+    int start = index;
+    switch (peek) {
+      case $EOF:
+        return null;
+      case $PERIOD:
+        advance();
+        return isDigit(peek) ? scanNumber(start) : new Token(start, '.');
+      case $LPAREN:
+        return scanCharacter(start, '(');
+      case $RPAREN:
+        return scanCharacter(start, ')');
+      case $LBRACE:
+        return scanCharacter(start, '{');
+      case $RBRACE:
+        return scanCharacter(start, '}');
+      case $LBRACKET:
+        return scanCharacter(start, '[');
+      case $RBRACKET:
+        return scanCharacter(start, ']');
+      case $COMMA:
+        return scanCharacter(start, ',');
+      case $COLON:
+        return scanCharacter(start, ':');
+      case $SEMICOLON:
+        return scanCharacter(start, ';');
+      case $SQ:
+      case $DQ:
+        return scanString();
+      case $PLUS:
+        return scanOperator(start, '+');
+      case $MINUS:
+        return scanOperator(start, '-');
+      case $STAR:
+        return scanOperator(start, '*');
+      case $SLASH:
+        return scanOperator(start, '/');
+      case $PERCENT:
+        return scanOperator(start, '%');
+      case $CARET:
+        return scanOperator(start, '^');
+      case $QUESTION:
+        return scanOperator(start, '?');
+      case $LT:
+        return scanComplexOperator(start, $EQ, '<', '<=');
+      case $GT:
+        return scanComplexOperator(start, $EQ, '>', '>=');
+      case $BANG:
+        return scanComplexOperator(start, $EQ, '!', '!=');
+      case $EQ:
+        return scanComplexOperator(start, $EQ, '=', '==');
+      case $AMPERSAND:
+        return scanComplexOperator(start, $AMPERSAND, '&', '&&');
+      case $BAR:
+        return scanComplexOperator(start, $BAR, '|', '||');
+      case $TILDE:
+        return scanComplexOperator(start, $SLASH, '~', '~/');
+    }
+
+    String character = new String.fromCharCode(peek);
+    error('Unexpected character [$character]');
+  }
+
+  Token scanCharacter(int start, String string) {
+    assert(peek == string.codeUnitAt(0));
+    advance();
+    return new Token(start, string);
+  }
+
+  Token scanOperator(int start, String string) {
+    assert(peek == string.codeUnitAt(0));
+    assert(OPERATORS.containsKey(string));
+    advance();
+    return new Token(start, string)..withOp(string);
+  }
+
+  Token scanComplexOperator(int start, int code, String one, String two) {
+    assert(peek == one.codeUnitAt(0));
+    advance();
+    String string = one;
+    if (peek == code) {
+      advance();
+      string = two;
+    }
+    assert(OPERATORS.containsKey(string));
+    return new Token(start, string)..withOp(string);
+  }
+
+  Token scanIdentifier() {
+    assert(isIdentifierStart(peek));
+    int start = index;
+    int dot = -1;
+    advance();
+    while (true) {
+      if (peek == $PERIOD) {
+        dot = index;
+      } else if (!isIdentifierPart(peek)) {
+        break;
+      }
+      advance();
+    }
+    if (dot == -1) {
+      String string = input.substring(start, index);
+      Token result = new Token(start, string);
+      // TODO(kasperl): Deal with null, undefined, true, and false in
+      // a cleaner and faster way.
+      if (OPERATORS.containsKey(string)) {
+        result.withOp(string);
+      } else {
+        result.withGetterSetter(string);
+      }
+      return result;
+    }
+
+    int end = index;
+    while (isWhitespace(peek)) advance();
+    if (peek == $LPAREN) {
+      buffer.add(new Token(dot + 1, input.substring(dot + 1, end)));
+      buffer.add(new Token(dot, '.'));
+      end = dot;
+    }
+    String string = input.substring(start, end);
+    return new Token(start, string)..withGetterSetter(string);
+  }
+
+  Token scanNumber(int start) {
+    assert(isDigit(peek));
+    bool simple = (index == start);
+    while (true) {
+      if (isDigit(peek)) {
+        // Do nothing.
+      } else if (peek == $PERIOD) {
+        simple = false;
+      } else if (isExponentStart(peek)) {
+        advance();
+        if (isExponentSign(peek)) advance();
+        if (!isDigit(peek)) error('Invalid exponent', -1);
+        simple = false;
+      } else {
+        break;
+      }
+      advance();
+    }
+    String string = input.substring(start, index);
+    num value = simple ? int.parse(string) : double.parse(string);
+    return new Token(start, string)..withValue(value);
+  }
+
+  Token scanString() {
+    assert(peek == $SQ || peek == $DQ);
+    int start = index;
+    int quote = peek;
+    advance();  // Skip initial quote.
+
+    StringBuffer buffer;
+    int marker = index;
+
+    while (peek != quote) {
+      if (peek == $BACKSLASH) {
+        if (buffer == null) buffer = new StringBuffer();
+        buffer.write(input.substring(marker, index));
+        advance();
+        int unescaped;
+        if (peek == $u) {
+          // TODO(kasperl): Check bounds? Make sure we have test
+          // coverage for this.
+          String hex = input.substring(index + 1, index + 5);
+          unescaped = int.parse(hex, radix: 16, onError: (ignore) {
+            error('Invalid unicode escape [\\u$hex]'); });
+          for (int i = 0; i < 5; i++) advance();
+        } else {
+          unescaped = unescape(peek);
+          advance();
+        }
+        buffer.writeCharCode(unescaped);
+        marker = index;
+      } else if (peek == $EOF) {
+        error('Unterminated quote');
+      } else {
+        advance();
+      }
+    }
+
+    String last = input.substring(marker, index);
+    advance();  // Skip terminating quote.
+    String string = input.substring(start, index);
+
+    // Compute the unescaped string value.
+    String unescaped = last;
+    if (buffer != null) {
+      buffer.write(last);
+      unescaped = buffer.toString();
+    }
+    return new Token(start, string)..withValue(unescaped);
+  }
+
+  void advance() {
+    if (++index >= length) peek = $EOF;
+    else peek = input.codeUnitAt(index);
+  }
+
+  void error(String message, [int offset = 0]) {
+    // TODO(kasperl): Try to get rid of the offset. It is only used to match
+    // the error expectations in the lexer tests for numbers with exponents.
+    int position = index + offset;
+    throw "Lexer Error: $message at column $position in expression [$input]";
+  }
+}