/// <summary>
/// Parses a function definition.
/// </summary>
/// <remarks>
/// Assumes the 'function' keyword has already been consumed.
/// </remarks>
internal static ExpressionBase Parse(PositionalTokenizer tokenizer, int line = 0, int column = 0)
{
var locationStart = new TextLocation(line, column); // location of 'function' keyword
ExpressionBase.SkipWhitespace(tokenizer);
line = tokenizer.Line;
column = tokenizer.Column;
var functionName = tokenizer.ReadIdentifier();
var functionNameVariable = new VariableDefinitionExpression(functionName.ToString(), line, column);
var function = new UserFunctionDefinitionExpression(functionNameVariable);
function.Location = new TextRange(locationStart.Line, locationStart.Column, 0, 0);
if (functionName.IsEmpty)
{
return(ExpressionBase.ParseError(tokenizer, "Invalid function name"));
}
return(function.Parse(tokenizer));
}
private static ExpressionBase ParseClauseCore(PositionalTokenizer tokenizer)
{
ExpressionBase clause;
switch (tokenizer.NextChar)
{
case '!':
tokenizer.Advance();
clause = ParseClause(tokenizer);
if (clause.Type == ExpressionType.ParseError)
{
return(clause);
}
return(new ConditionalExpression(null, ConditionalOperation.Not, clause));
case '(':
if (AnonymousUserFunctionDefinitionExpression.IsAnonymousParameterList(tokenizer))
{
return(AnonymousUserFunctionDefinitionExpression.ParseAnonymous(tokenizer));
}
tokenizer.Advance();
clause = ExpressionBase.Parse(tokenizer);
if (clause.Type == ExpressionType.ParseError)
{
return(clause);
}
if (tokenizer.NextChar != ')')
{
if (tokenizer.NextChar == '\0')
{
return(ParseError(tokenizer, "No closing parenthesis found"));
}
return(ParseError(tokenizer, "Expected closing parenthesis, found: " + tokenizer.NextChar));
}
clause.IsLogicalUnit = true;
tokenizer.Advance();
return(clause);
case '"':
try
{
var stringValue = tokenizer.ReadQuotedString().ToString();
return(new StringConstantExpression(stringValue));
}
catch (InvalidOperationException ex)
{
return(ParseError(tokenizer, ex.Message));
}
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
return(ParseNumber(tokenizer, true));
case '-':
var tokenStart = tokenizer.Location;
tokenizer.Advance();
if (tokenizer.NextChar >= '0' && tokenizer.NextChar <= '9')
{
var result = ParseNumber(tokenizer, false);
var tokenEnd = result.Location.End;
switch (result.Type)
{
case ExpressionType.IntegerConstant:
result = new IntegerConstantExpression(-((IntegerConstantExpression)result).Value);
break;
case ExpressionType.FloatConstant:
result = new FloatConstantExpression(-((FloatConstantExpression)result).Value);
break;
default:
return(result);
}
result.Location = new TextRange(tokenStart, tokenEnd);
return(result);
}
return(ParseError(tokenizer, "Minus without value", tokenStart.Line, tokenStart.Column));
case '{':
tokenizer.Advance();
return(DictionaryExpression.Parse(tokenizer));
case '[':
tokenizer.Advance();
return(ParseArray(tokenizer));
default:
var line = tokenizer.Line;
var column = tokenizer.Column;
var identifier = tokenizer.ReadIdentifier();
if (identifier.IsEmpty)
{
var error = ParseError(tokenizer, "Unexpected character: " + tokenizer.NextChar);
tokenizer.Advance();
return(error);
}
SkipWhitespace(tokenizer);
if (identifier == "return")
{
clause = ExpressionBase.Parse(tokenizer);
if (clause.Type == ExpressionType.ParseError)
{
return(clause);
}
return(new ReturnExpression(new KeywordExpression(identifier.ToString(), line, column), clause));
}
if (identifier == "function")
{
return(UserFunctionDefinitionExpression.Parse(tokenizer, line, column));
}
if (identifier == "for")
{
return(ForExpression.Parse(tokenizer, line, column));
}
if (identifier == "if")
{
return(IfExpression.Parse(tokenizer, line, column));
}
if (identifier == "true")
{
return(new BooleanConstantExpression(true, line, column));
}
if (identifier == "false")
{
return(new BooleanConstantExpression(false, line, column));
}
if (tokenizer.NextChar == '(')
{
tokenizer.Advance();
var parameters = new List <ExpressionBase>();
ParseParameters(tokenizer, parameters);
var functionCall = new FunctionCallExpression(new FunctionNameExpression(identifier.ToString(), line, column), parameters);
functionCall.Location = new TextRange(line, column, tokenizer.Line, tokenizer.Column - 1);
return(functionCall);
}
if (tokenizer.NextChar == '[')
{
IndexedVariableExpression parent = null;
do
{
tokenizer.Advance();
var index = ExpressionBase.Parse(tokenizer);
if (index.Type == ExpressionType.ParseError)
{
return(index);
}
SkipWhitespace(tokenizer);
if (tokenizer.NextChar != ']')
{
return(ParseError(tokenizer, "Expecting closing bracket after index"));
}
tokenizer.Advance();
SkipWhitespace(tokenizer);
if (parent != null)
{
parent = new IndexedVariableExpression(parent, index);
}
else
{
parent = new IndexedVariableExpression(new VariableExpression(identifier.ToString(), line, column), index);
}
} while (tokenizer.NextChar == '[');
return(parent);
}
return(new VariableExpression(identifier.ToString(), line, column));
}
}
