/// <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));
}
protected new ExpressionBase Parse(PositionalTokenizer tokenizer)
{
ExpressionBase.SkipWhitespace(tokenizer);
if (tokenizer.NextChar != '(')
{
return(ExpressionBase.ParseError(tokenizer, "Expected '(' after function name", Name));
}
tokenizer.Advance();
ExpressionBase.SkipWhitespace(tokenizer);
if (tokenizer.NextChar != ')')
{
do
{
var line = tokenizer.Line;
var column = tokenizer.Column;
var parameter = tokenizer.ReadIdentifier();
if (parameter.IsEmpty)
{
return(ExpressionBase.ParseError(tokenizer, "Invalid parameter name", line, column));
}
var variableDefinition = new VariableDefinitionExpression(parameter.ToString(), line, column);
Parameters.Add(variableDefinition);
ExpressionBase.SkipWhitespace(tokenizer);
if (tokenizer.NextChar == '=')
{
tokenizer.Advance();
ExpressionBase.SkipWhitespace(tokenizer);
var value = ExpressionBase.Parse(tokenizer);
if (value.Type == ExpressionType.ParseError)
{
return(ExpressionBase.ParseError(tokenizer, "Invalid default value for " + parameter.ToString(), value));
}
var scope = new InterpreterScope(AchievementScriptInterpreter.GetGlobalScope());
scope.Context = new TriggerBuilderContext(); // prevent errors passing memory references as default parameters
ExpressionBase evaluated;
if (!value.ReplaceVariables(scope, out evaluated))
{
return(ExpressionBase.ParseError(tokenizer, "Default value for " + parameter.ToString() + " is not constant", evaluated));
}
DefaultParameters[parameter.ToString()] = evaluated;
}
else if (DefaultParameters.Count > 0)
{
return(ExpressionBase.ParseError(tokenizer,
string.Format("Non-default parameter {0} appears after default parameters", parameter.ToString()), variableDefinition));
}
if (tokenizer.NextChar == ')')
{
break;
}
if (tokenizer.NextChar != ',')
{
return(ExpressionBase.ParseError(tokenizer, "Expected ',' or ')' after parameter name, found: " + tokenizer.NextChar));
}
tokenizer.Advance();
ExpressionBase.SkipWhitespace(tokenizer);
} while (true);
}
tokenizer.Advance(); // closing parenthesis
ExpressionBase.SkipWhitespace(tokenizer);
ExpressionBase expression;
if (tokenizer.Match("=>"))
{
return(ParseShorthandBody(tokenizer));
}
if (tokenizer.NextChar != '{')
{
return(ExpressionBase.ParseError(tokenizer, "Expected '{' after function declaration", Name));
}
tokenizer.Advance();
ExpressionBase.SkipWhitespace(tokenizer);
bool seenReturn = false;
while (tokenizer.NextChar != '}')
{
expression = ExpressionBase.Parse(tokenizer);
if (expression.Type == ExpressionType.ParseError)
{
// the ExpressionTokenizer will capture the error, we should still return the incomplete FunctionDefinition
if (tokenizer is ExpressionTokenizer)
{
break;
}
// not an ExpressionTokenizer, just return the error
return(expression);
}
if (expression.Type == ExpressionType.Return)
{
seenReturn = true;
}
else if (seenReturn)
{
ExpressionBase.ParseError(tokenizer, "Expression after return statement", expression);
}
Expressions.Add(expression);
ExpressionBase.SkipWhitespace(tokenizer);
}
Location = new TextRange(Location.Start, tokenizer.Location);
tokenizer.Advance();
return(MakeReadOnly(this));
}
/// <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 function = new FunctionDefinitionExpression();
function._keyword = new KeywordExpression("function", line, column);
ExpressionBase.SkipWhitespace(tokenizer);
line = tokenizer.Line;
column = tokenizer.Column;
var functionName = tokenizer.ReadIdentifier();
function.Name = new VariableDefinitionExpression(functionName.ToString(), line, column);
if (functionName.IsEmpty)
{
ExpressionBase.ParseError(tokenizer, "Invalid function name");
return(function);
}
ExpressionBase.SkipWhitespace(tokenizer);
if (tokenizer.NextChar != '(')
{
ExpressionBase.ParseError(tokenizer, "Expected '(' after function name", function.Name);
return(function);
}
tokenizer.Advance();
ExpressionBase.SkipWhitespace(tokenizer);
if (tokenizer.NextChar != ')')
{
do
{
line = tokenizer.Line;
column = tokenizer.Column;
var parameter = tokenizer.ReadIdentifier();
if (parameter.IsEmpty)
{
ExpressionBase.ParseError(tokenizer, "Invalid parameter name", line, column);
return(function);
}
function.Parameters.Add(new VariableDefinitionExpression(parameter.ToString(), line, column));
ExpressionBase.SkipWhitespace(tokenizer);
if (tokenizer.NextChar == ')')
{
break;
}
if (tokenizer.NextChar != ',')
{
ExpressionBase.ParseError(tokenizer, "Expected ',' or ')' after parameter name, found: " + tokenizer.NextChar);
return(function);
}
tokenizer.Advance();
ExpressionBase.SkipWhitespace(tokenizer);
} while (true);
}
tokenizer.Advance(); // closing parenthesis
ExpressionBase.SkipWhitespace(tokenizer);
ExpressionBase expression;
if (tokenizer.Match("=>"))
{
ExpressionBase.SkipWhitespace(tokenizer);
expression = ExpressionBase.Parse(tokenizer);
if (expression.Type == ExpressionType.ParseError)
{
return(expression);
}
if (expression.Type == ExpressionType.Return)
{
return(new ParseErrorExpression("Return statement is implied by =>", ((ReturnExpression)expression).Keyword));
}
var returnExpression = new ReturnExpression(expression);
function.Expressions.Add(returnExpression);
return(function);
}
if (tokenizer.NextChar != '{')
{
ExpressionBase.ParseError(tokenizer, "Expected '{' after function declaration", function.Name);
return(function);
}
line = tokenizer.Line;
column = tokenizer.Column;
tokenizer.Advance();
ExpressionBase.SkipWhitespace(tokenizer);
bool seenReturn = false;
while (tokenizer.NextChar != '}')
{
expression = ExpressionBase.Parse(tokenizer);
if (expression.Type == ExpressionType.ParseError)
{
return(expression);
}
if (expression.Type == ExpressionType.Return)
{
seenReturn = true;
}
else if (seenReturn)
{
ExpressionBase.ParseError(tokenizer, "Expression after return statement", expression);
}
function.Expressions.Add(expression);
ExpressionBase.SkipWhitespace(tokenizer);
}
tokenizer.Advance();
return(function);
}
