/// <summary>
/// Parses a for loop.
/// </summary>
/// <remarks>
/// Assumes the 'for' keyword has already been consumed.
/// </remarks>
internal static ExpressionBase Parse(PositionalTokenizer tokenizer, int line = 0, int column = 0)
{
ExpressionBase.SkipWhitespace(tokenizer);
var keywordFor = new KeywordExpression("for", line, column);
line = tokenizer.Line;
column = tokenizer.Column;
var iteratorName = tokenizer.ReadIdentifier();
if (iteratorName.IsEmpty)
{
return(ParseError(tokenizer, "Invalid function name", line, column));
}
var iterator = new VariableDefinitionExpression(iteratorName.ToString(), line, column);
ExpressionBase.SkipWhitespace(tokenizer);
line = tokenizer.Line;
column = tokenizer.Column;
if (!tokenizer.Match("in"))
{
return(ParseError(tokenizer, "Expected 'in' after loop variable"));
}
var keywordIn = new KeywordExpression("in", line, column);
var range = ExpressionBase.Parse(tokenizer);
if (range.Type == ExpressionType.ParseError)
{
return(range);
}
var loop = new ForExpression(iterator, range);
var error = ExpressionBase.ParseStatementBlock(tokenizer, loop.Expressions);
if (error != null)
{
return(error);
}
loop._keywordFor = keywordFor;
loop._keywordIn = keywordIn;
loop.Line = keywordFor.Line;
loop.Column = keywordFor.Column;
loop.EndLine = tokenizer.Line;
loop.EndColumn = tokenizer.Column;
return(loop);
}
/// <summary>
/// Parses a if definition.
/// </summary>
/// <remarks>
/// Assumes the 'if' keyword has already been consumed.
/// </remarks>
internal static ExpressionBase Parse(PositionalTokenizer tokenizer, int line = 0, int column = 0)
{
ExpressionBase.SkipWhitespace(tokenizer);
var condition = ExpressionBase.Parse(tokenizer);
if (condition.Type == ExpressionType.ParseError)
{
return(condition);
}
if (condition.Type != ExpressionType.Conditional && condition.Type != ExpressionType.Comparison)
{
return(ParseError(tokenizer, "Expected conditional statement following if", condition));
}
var ifExpression = new IfExpression(condition);
ifExpression._keyword = new KeywordExpression("if", line, column);
var error = ExpressionBase.ParseStatementBlock(tokenizer, ifExpression.Expressions);
if (error != null)
{
return(error);
}
ExpressionBase.SkipWhitespace(tokenizer);
if (tokenizer.Match("else"))
{
error = ExpressionBase.ParseStatementBlock(tokenizer, ifExpression.ElseExpressions);
if (error != null)
{
return(error);
}
}
return(ifExpression);
}
/// <summary>
/// Parses a if definition.
/// </summary>
/// <remarks>
/// Assumes the 'if' keyword has already been consumed.
/// </remarks>
internal static ExpressionBase Parse(PositionalTokenizer tokenizer, int line = 0, int column = 0)
{
ExpressionBase.SkipWhitespace(tokenizer);
var condition = ExpressionBase.Parse(tokenizer);
if (condition.Type == ExpressionType.ParseError)
{
return(condition);
}
var ifExpression = new IfExpression(condition);
ifExpression._keyword = new KeywordExpression("if", line, column);
var error = ExpressionBase.ParseStatementBlock(tokenizer, ifExpression.Expressions);
if (error != null)
{
return(error);
}
ExpressionBase.SkipWhitespace(tokenizer);
line = tokenizer.Line;
column = tokenizer.Column;
if (tokenizer.Match("else"))
{
ifExpression._elseKeyword = new KeywordExpression("else", line, column);
error = ExpressionBase.ParseStatementBlock(tokenizer, ifExpression.ElseExpressions);
if (error != null)
{
return(error);
}
}
return(ifExpression);
}
