private static Statement ParseStatement(Scanner scanner)
{
if (scanner.TryGetIdentifier("if"))
{
scanner.GetDelimiter("(");
Expression condition = ParseExpression(scanner);
scanner.GetDelimiter(")");
Statement thenstatement = ParseStatement(scanner);
Statement elsestatement = new NullStatement();
if (scanner.TryGetIdentifier("else"))
{
elsestatement = ParseStatement(scanner);
}
return new IfStatement(condition,thenstatement,elsestatement);
}
else if (scanner.TryGetIdentifier("while"))
{
scanner.GetDelimiter("(");
Expression condition = ParseExpression(scanner);
scanner.GetDelimiter(")");
Statement loopstatement = ParseStatement(scanner);
Statement elsestatement = new NullStatement();
if (scanner.TryGetIdentifier("else"))
{
elsestatement = ParseStatement(scanner);
}
return new WhileStatement(condition,loopstatement,elsestatement);
}
else if (scanner.TryGetIdentifier("foreach"))
{
scanner.GetDelimiter("(");
string variabletype;
string variablename;
scanner.GetIdentifier(out variabletype);
scanner.GetIdentifier(out variablename);
scanner.GetIdentifier("in");
Expression collection = ParseExpression(scanner);
scanner.GetDelimiter(")");
Statement loopstatement = ParseStatement(scanner);
Statement elsestatement = new NullStatement();
if (scanner.TryGetIdentifier("else"))
{
elsestatement = ParseStatement(scanner);
}
return new ForEachStatement(variabletype,variablename,collection,loopstatement,elsestatement);
}
else if (scanner.TryGetIdentifier("var"))
{
string variablename;
scanner.GetIdentifier(out variablename);
scanner.GetDelimiter("=");
Expression expression = ParseExpression(scanner);
scanner.GetDelimiter(";");
return new VarStatement(variablename,expression);
}
else if (scanner.TryGetIdentifier("return"))
{
if (scanner.TryGetDelimiter(";"))
{
return new ReturnStatement(null);
}
else
{
Expression expression = ParseExpression(scanner);
scanner.GetDelimiter(";");
return new ReturnStatement(expression);
}
}
else if (scanner.TryGetDelimiter("{"))
{
return CodeParser.ParseBlock(scanner.ScanAcross("{","}"));
}
else if (scanner.TryGetDelimiter(";"))
{
return new NullStatement();
}
else
{
Expression expression = ParseExpression(scanner);
scanner.GetDelimiter(";");
return new ExpressionStatement(expression);
}
}
private static Statement ParseStatement(Scanner scanner)
{
if (scanner.TryGetIdentifier("if"))
{
scanner.GetDelimiter("(");
Expression condition = ParseExpression(scanner);
scanner.GetDelimiter(")");
Statement thenstatement = ParseStatement(scanner);
Statement elsestatement = new NullStatement();
if (scanner.TryGetIdentifier("else"))
{
elsestatement = ParseStatement(scanner);
}
return(new IfStatement(condition, thenstatement, elsestatement));
}
else if (scanner.TryGetIdentifier("while"))
{
scanner.GetDelimiter("(");
Expression condition = ParseExpression(scanner);
scanner.GetDelimiter(")");
Statement loopstatement = ParseStatement(scanner);
Statement elsestatement = new NullStatement();
if (scanner.TryGetIdentifier("else"))
{
elsestatement = ParseStatement(scanner);
}
return(new WhileStatement(condition, loopstatement, elsestatement));
}
else if (scanner.TryGetIdentifier("foreach"))
{
scanner.GetDelimiter("(");
string variabletype;
string variablename;
scanner.GetIdentifier(out variabletype);
scanner.GetIdentifier(out variablename);
scanner.GetIdentifier("in");
Expression collection = ParseExpression(scanner);
scanner.GetDelimiter(")");
Statement loopstatement = ParseStatement(scanner);
Statement elsestatement = new NullStatement();
if (scanner.TryGetIdentifier("else"))
{
elsestatement = ParseStatement(scanner);
}
return(new ForEachStatement(variabletype, variablename, collection, loopstatement, elsestatement));
}
else if (scanner.TryGetIdentifier("var"))
{
string variablename;
scanner.GetIdentifier(out variablename);
scanner.GetDelimiter("=");
Expression expression = ParseExpression(scanner);
scanner.GetDelimiter(";");
return(new VarStatement(variablename, expression));
}
else if (scanner.TryGetIdentifier("return"))
{
if (scanner.TryGetDelimiter(";"))
{
return(new ReturnStatement(null));
}
else
{
Expression expression = ParseExpression(scanner);
scanner.GetDelimiter(";");
return(new ReturnStatement(expression));
}
}
else if (scanner.TryGetDelimiter("{"))
{
return(CodeParser.ParseBlock(scanner.ScanAcross("{", "}")));
}
else if (scanner.TryGetDelimiter(";"))
{
return(new NullStatement());
}
else
{
Expression expression = ParseExpression(scanner);
scanner.GetDelimiter(";");
return(new ExpressionStatement(expression));
}
}