public void LexerBackTrackingThrowsIfCalledWithNonFullBufferTooManyTimes()
{
var reporter = new ErrorReporter();
var lexer = new Lexer(@"..\..\example_program.txt", reporter);
bool throws = false;
try
{
lexer.Backtrack();
}
catch (InternalCompilerError e)
{
throws = true;
}
Assert.IsTrue(throws);
Assert.AreEqual(0, reporter.Errors.Count);
}
public void LexerPeekingWorksWithBacktracking()
{
var reporter = new ErrorReporter();
var lexer = new Lexer(@"..\..\example_program.txt", reporter);
lexer.NextToken();
lexer.NextToken();
lexer.NextToken();
Assert.AreEqual(new VarToken(), lexer.PeekToken());
lexer.Backtrack();
Assert.AreEqual(new SemicolonToken(), lexer.PeekToken());
Assert.AreEqual(new SemicolonToken(), lexer.NextToken());
Assert.AreEqual(new VarToken(), lexer.PeekToken());
Assert.AreEqual(new VarToken(), lexer.PeekToken());
lexer.Backtrack();
lexer.Backtrack();
Assert.AreEqual(new TextToken("Give a number"), lexer.PeekToken());
Assert.AreEqual(new TextToken("Give a number"), lexer.NextToken());
Assert.AreEqual(0, reporter.Errors.Count);
}
public void LexerBackTrackingThrowsIfCalledTooManyTimes()
{
var reporter = new ErrorReporter();
var lexer = new Lexer(@"..\..\example_program.txt", reporter);
Assert.AreEqual(new PrintToken(), lexer.NextToken());
Assert.AreEqual(new TextToken("Give a number"), lexer.NextToken());
Assert.AreEqual(new SemicolonToken(), lexer.NextToken());
lexer.NextToken();
for (int i = 0; i < Lexer.BACKTRACK_BUFFER_SIZE; ++i)
{
lexer.Backtrack();
}
bool throws = false;
try
{
lexer.Backtrack();
} catch (InternalCompilerError e)
{
throws = true;
}
Assert.IsTrue(throws);
Assert.AreEqual(0, reporter.Errors.Count);
}