Start adding files for Dart version of test script test.py.

tools/testing/dart/status_expressions_lib.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#library("status_expressions");
+
+/**
+ *  Parse and evaluate expressions in a .status file for Dart and V8.

[ngeoffray, 2011/10/26 12:01:37]

Extra space.

+ * There are set expressions and Boolean expressions in a .status file.
+ * The grammar is:
+ *   BooleanExpression := $variable_name == value |
+ *                        (BooleanExpression) | 
+ *                        BooleanExpression && BooleanExpression | 
+ *                        BooleanExpression || BooleanExpression
+ *
+ *   SetExpression := value | (SetExpression) |
+ *                    SetExpression || SetExpression |
+ *                    SetExpression if BooleanExpression |
+ *                    SetExpression , SetExpression
+ *
+ *   Production are listed in order of precedence, and the || and , operators

[Mads Ager (google), 2011/10/26 12:37:47]

Remove the extra leading space starting from here as well?

+ *   both evaluate to set union, but with different precedence.
+ *
+ *   Values and names are non-empty strings of word characters, matching
+ *   the RegExp \w+.
+ *
+ *   Expressions evaluate as expected, with values of variables found in
+ *   an environment passed to the evaluator.  The SetExpression "value"
+ *   evaluates to a singleton set containing that value. "A if B" evaluates
+ *   to A if B is true, and to the empty set if B is false.
+ */
+
+class Tokenizer {
+  String expression;
+  List<String> tokens;
+
+  Tokenizer(String this.expression)

[Søren Gjesse, 2011/10/26 13:36:24]

Fit on one line?

+    : tokens = new List<String>();
+
+  /**
+   *  Tokens are : "&&", "||", "==", "$", "(", ")", ",", and (maximal) \w+.

[Søren Gjesse, 2011/10/26 13:36:24]

Maybe list the tokens in the same order as they are matched by the regexp.

+   */
+  static final test_regexp =
+      const RegExp(@"^([()$\w\s,]|(\&\&)|(\|\|)|(\=\=))+$");
+  static final regexp = const RegExp(@"[()$,]|(\&\&)|(\|\|)|(\=\=)|\w+");
+
+  void tokenize() {
+    if (!test_regexp.hasMatch(expression)) {
+      throw new ExpectException("Syntax error in '" + expression + '"');
+    }
+    for (Match match in regexp.allMatches(expression)) tokens.add(match[0]);
+  }
+}
+
+
+interface BooleanExpression {
+  bool evaluate(Map<String, String> environment);
+}
+
+
+interface SetExpression {
+  // A set of test outcomes.

[Mads Ager (google), 2011/10/26 12:37:47]

Please update the comment here to actually describe the method. Or delete the
comment.

+  Set<String> evaluate(Map<String, String> environment);
+}
+
+
+class Comparison implements BooleanExpression {
+  Variable left;
+  TermConstant right;
+
+  Comparison(this.left, this.right);
+
+  bool evaluate(environment) => left.termValue() == right.termValue();
+  String toString() => "==(\$${left.name}, ${right.value})";

[Mads Ager (google), 2011/10/26 12:37:47]

Why not just "(\$${left.name} == ${right.value})"?

+}
+
+class Variable {
+  String name;
+  Variable(String this.name);
+
+  String termValue(environment) => environment[name];
+}
+
+class TermConstant {
+  String value;
+  TermConstant(String this.value);
+
+  String termValue(environment) => value;
+}
+     
+
+class BooleanOperation implements BooleanExpression {
+  String op;
+  BooleanExpression left;
+  BooleanExpression right;
+
+  BooleanOperation(this.op, this.left, this.right);
+
+  bool evaluate(environment) => (op == "&&") ?
+      left.evaluate(environment) && right.evaluate(environment) :
+      left.evaluate(environment) || right.evaluate(environment);
+  String toString() => "$op(${left.toString()},${right.toString()})";

[Mads Ager (google), 2011/10/26 12:37:47]

I would go for infix here and in the rest.

+}
+
+class SetUnion implements SetExpression {
+  SetExpression left;
+  SetExpression right;
+
+  SetUnion(this.left, this.right);
+
+  // Overwrites left.evaluate(env).
+  Set<String> evaluate(environment) =>
+      left.evaluate(environment).addAll(right.evaluate(environment));
+  String toString() => "||(${left.toString()},${right.toString()})";
+}
+
+class SetIf implements SetExpression {
+  SetExpression left;
+  BooleanExpression right;
+
+  SetIf(this.left, this.right);
+
+  Set<String> evaluate(environment) => right.evaluate(environment) ?
+    left.evaluate(environment) : new Set<String>();
+  String toString() => "if(${left.toString()},${right.toString()})";
+}
+    
+
+class SetConstant implements SetExpression {
+  String value;
+
+  SetConstant(this.value);
+
+  Set<String> evaluate(environment) => new Set<string>().add(value);
+  String toString() => value;
+}
+
+
+/* An iterator that provides peeking at the current token. */

[Mads Ager (google), 2011/10/26 12:37:47]

I think you should either make this a doc comment and use /** or just use //.

[William Hesse, 2011/10/26 15:15:03]

Done.

+class Scanner {

[Søren Gjesse, 2011/10/26 13:36:24]

Should we have token constants?

class Token {
  final String AND = "&&";
  final String OR = "||";
  ...

}

[William Hesse, 2011/10/26 15:15:03]

Done.

+  List<String> tokens;
+  Iterator token_iterator;
+  String current;
+
+  Scanner(this.tokens) {
+    //print(tokens[0] + tokens[1]);

[Mads Ager (google), 2011/10/26 12:37:47]

remove.

[William Hesse, 2011/10/26 15:15:03]

Done.

+    token_iterator = tokens.iterator();
+    current = token_iterator.next();

[Mads Ager (google), 2011/10/26 12:37:47]

Shouldn't this just call advance?

[William Hesse, 2011/10/26 15:15:03]

Done.

+    //print(current);

[Mads Ager (google), 2011/10/26 12:37:47]

remove.

[William Hesse, 2011/10/26 15:15:03]

Done.

+  }
+
+  bool hasMore() => current != null;
+
+  void advance() {
+    current = token_iterator.hasNext() ? token_iterator.next() : null;
+    print(current);

[Mads Ager (google), 2011/10/26 12:37:47]

remove

[William Hesse, 2011/10/26 15:15:03]

Done.

+  }
+}
+
+class ExpressionParser {
+  Scanner scanner;

[Søren Gjesse, 2011/10/26 13:36:24]

Empty line before the constructor.

[William Hesse, 2011/10/26 15:15:03]

Done.

+  ExpressionParser(this.scanner);
+
+  SetExpression parseSetExpression() => parseSetUnion();
+
+  SetExpression parseSetUnion() {
+    SetExpression left = parseSetIf();
+    while (scanner.hasMore() && scanner.current == ","){
+      scanner.advance();
+      SetExpression right = parseSetIf();
+      left = new SetUnion(left, right);
+    }
+    return left;
+  }
+
+  SetExpression parseSetIf() {
+    SetExpression left = parseSetOr();
+    while (scanner.hasMore() && scanner.current == "if") {
+      scanner.advance();
+      BooleanExpression right = parseBooleanExpression();
+      left = new SetIf(left, right);
+    }
+    return left;
+  }
+
+  SetExpression parseSetOr() {
+    SetExpression left = parseSetAtomic();
+    while (scanner.hasMore() && scanner.current == "||"){
+      scanner.advance();
+      SetExpression right = parseSetIf();
+      left = new SetUnion(left, right);
+    }
+    return left;
+  }
+
+
+  SetExpression parseSetAtomic() {
+    if (scanner.current == "(") {
+      scanner.advance();
+      SetExpression value = parseSetUnion();
+      Expect.equals(scanner.current, ")",
+          "Missing right parenthesis in expression");

[Mads Ager (google), 2011/10/26 12:37:47]

Please align with first parameter.

[William Hesse, 2011/10/26 15:15:03]

Done.

+      scanner.advance();
+      return value;
+    }
+    Expect.isTrue(const RegExp(@"^\w+$").hasMatch(scanner.current),
+          "Expected identifier in expression, got " + scanner.current);

[Mads Ager (google), 2011/10/26 12:37:47]

Please align with first parameter or move both to new lines.

[William Hesse, 2011/10/26 15:15:03]

Done.

+    SetExpression value = new SetConstant(scanner.current);
+    scanner.advance();
+    return value;
+  }
+
+  BooleanExpression parseBooleanExpression() => parseBooleanOr();
+
+  BooleanExpression parseBooleanOr() {
+    BooleanExpression left = parseBooleanAnd();
+    while (scanner.hasMore() && scanner.current == "||") {
+      scanner.advance();
+      BooleanExpression right = parseBooleanAnd();
+      left = new BooleanOperation("||", left, right);
+    }
+    return left;
+  }
+
+
+  BooleanExpression parseBooleanAnd() {
+    BooleanExpression left = parseBooleanAtomic();
+    while (scanner.hasMore() && scanner.current == "&&") {
+      scanner.advance();
+      BooleanExpression right = parseBooleanAtomic();
+      left = new BooleanOperation("&&", left, right);
+    }
+    return left;
+  }
+
+  BooleanExpression parseBooleanAtomic() {
+    if (scanner.current == "(") {
+      scanner.advance();
+      SetExpression value = parseBooleanExpression();
+      Expect.equals(scanner.current, ")",
+          "Missing right parenthesis in expression");

[Mads Ager (google), 2011/10/26 12:37:47]

align

[William Hesse, 2011/10/26 15:15:03]

Done.

+      scanner.advance();
+      return value;
+    }
+
+    // The only atomic booleans are of the form $variable == value.
+    Expect.equals(scanner.current, @"$",
+        @"Expected $identifier in expression, got " + scanner.current);

[Mads Ager (google), 2011/10/26 12:37:47]

$identifier -> $

[William Hesse, 2011/10/26 15:15:03]

Done.

+    scanner.advance();
+    Expect.isTrue(const RegExp(@"^\w+$").hasMatch(scanner.current),
+        @"Expected $identifier in expression, got " + scanner.current);
+    Variable left = new Variable(scanner.current);
+    scanner.advance();
+    Expect.equals(scanner.current, "==",
+        "Expected == in expression, got " + scanner.current);
+    scanner.advance();
+    Expect.isTrue(const RegExp(@"^\w+$").hasMatch(scanner.current),
+        @"Expected identifier in expression, got " + scanner.current);

[Søren Gjesse, 2011/10/26 13:36:24]

No need for @ here.

[William Hesse, 2011/10/26 15:15:03]

Done.

+    TermConstant right = new TermConstant(scanner.current);
+    scanner.advance();
+    return new Comparison(left, right); 
+  }
+}
+