private ast.IStatement CompleteStatement(ast.IExpression expression)
{
if (expression == null) // there was a parse error in the expression
{
RecoverUntilPunctuationTokenAndConsume(";");
return null;
}
else if (Input.NextTokenIs<OperatorToken>("="))
{
return MakeAssignmentStatement(expression);
}
else if (expression is ast.MethodInvocation)
{
Input.MatchAndConsume<PunctuationToken>(";");
return (ast.MethodInvocation)expression;
}
else
{
var expr = (ast.SyntaxElement)expression;
throw new SyntaxError(String.Format("Expression of type {0} cannot form a statement on its own.", expression.Describe()),
expr.Row, expr.Col);
}
}
private ast.VariableDeclaration VariableOrFormalParameterDeclaration(ast.VariableDeclaration.Kind kind, params string[] followSet)
{
try
{
var typeInfo = Type();
var type = typeInfo.typeToken;
var variableIdent = Input.MatchAndConsume<IdentifierToken>();
return new ast.VariableDeclaration(variableIdent.Lexeme, type.Lexeme,
typeInfo.isArray, kind, type.Row, type.Col);
}
catch (SyntaxError e)
{
if (DebugMode) throw;
ErrorReporter.ReportError(ErrorTypes.Syntax, e.Message, e.Row, e.Col);
}
catch (LexicalError)
{
if (DebugMode) throw;
}
ParsingFailed = true;
RecoverFromVariableDeclarationMatching(followSet);
return null;
}
public bool TryParse(out ast.Program program)
{
program = Program();
return !ParsingFailed;
}
private ast.VariableDeclaration VariableDeclaration(ast.VariableDeclaration.Kind kind)
{
var variableDecl = VariableOrFormalParameterDeclaration(kind, ";");
Input.MatchAndConsume<PunctuationToken>(";");
return variableDecl;
}
private ast.IStatement MakeAssignmentStatement(ast.IExpression lhs)
{
var assignment = Input.MatchAndConsume<OperatorToken>("=");
ast.IExpression rhs = Expression();
Input.MatchAndConsume<PunctuationToken>(";");
return new ast.AssignmentStatement(lhs, rhs,
assignment.Row, assignment.Col);
}
