private bool GetSingleParameter(FunctionDefinitionExpression function, InterpreterScope parameterScope, out ExpressionBase error)
{
var funcParameter = function.Parameters.First();
ExpressionBase value = Parameters.First();
if (value.IsConstant)
{
// already a basic type, just proceed to storing it
error = null;
}
else
{
var assignedParameter = value as AssignmentExpression;
if (assignedParameter == null)
{
assignedParameter = new AssignmentExpression(new VariableExpression(funcParameter.Name), value);
}
else if (funcParameter.Name != assignedParameter.Variable.Name)
{
error = new ParseErrorExpression(String.Format("'{0}' does not have a '{1}' parameter", function.Name.Name, assignedParameter.Variable.Name), value);
return(true);
}
value = GetParameter(parameterScope, parameterScope, assignedParameter);
error = value as ParseErrorExpression;
if (error != null)
{
return(true);
}
}
parameterScope.DefineVariable(new VariableDefinitionExpression(funcParameter.Name), value);
return(true);
}
/// <summary>
/// Adds the function definition.
/// </summary>
public void AddFunction(FunctionDefinitionExpression function)
{
if (_functions == null)
{
_functions = new Dictionary <string, FunctionDefinitionExpression>();
}
_functions[function.Name.Name] = function;
}
/// <summary>
/// Creates a new scope for calling a function and populates values for parameters passed to the function.
/// </summary>
/// <param name="function">The function defining the parameters to populate.</param>
/// <param name="scope">The outer scope containing the function call.</param>
/// <param name="error">[out] A <see cref="ParseErrorExpression"/> indicating why constructing the new scope failed.</param>
/// <returns>The new scope, <c>null</c> if an error occurred - see <paramref name="error"/> for error details.</returns>
public InterpreterScope GetParameters(FunctionDefinitionExpression function, InterpreterScope scope, out ExpressionBase error)
{
var parameterScope = function.CreateCaptureScope(scope);
// optimization for no parameter function
if (function.Parameters.Count == 0 && Parameters.Count == 0)
{
error = null;
return(parameterScope);
}
// optimization for single parameter function
if (function.Parameters.Count == 1 && Parameters.Count == 1)
{
if (GetSingleParameter(function, parameterScope, out error))
{
return(parameterScope);
}
if (error != null)
{
return(null);
}
}
var providedParameters = new List <string>(function.Parameters.Count);
foreach (var parameter in function.Parameters)
{
providedParameters.Add(parameter.Name);
}
ArrayExpression varargs = null;
if (providedParameters.Remove("..."))
{
varargs = new ArrayExpression();
parameterScope.DefineVariable(new VariableDefinitionExpression("varargs"), varargs);
}
var parameterCount = providedParameters.Count;
int index = 0;
bool namedParameters = false;
foreach (var parameter in Parameters)
{
var assignedParameter = parameter as AssignmentExpression;
if (assignedParameter != null)
{
if (!providedParameters.Remove(assignedParameter.Variable.Name))
{
if (!function.Parameters.Any(p => p.Name == assignedParameter.Variable.Name))
{
error = new ParseErrorExpression(String.Format("'{0}' does not have a '{1}' parameter", function.Name.Name, assignedParameter.Variable.Name), parameter);
return(null);
}
error = new ParseErrorExpression(String.Format("'{0}' already has a value", assignedParameter.Variable.Name), assignedParameter.Variable);
return(null);
}
var value = GetParameter(parameterScope, scope, assignedParameter);
error = value as ParseErrorExpression;
if (error != null)
{
return(null);
}
parameterScope.DefineVariable(new VariableDefinitionExpression(assignedParameter.Variable), value);
namedParameters = true;
}
else
{
if (namedParameters)
{
error = new ParseErrorExpression("Non-named parameter following named parameter", parameter);
return(null);
}
if (index >= parameterCount && varargs == null)
{
error = new ParseErrorExpression("Too many parameters passed to function", parameter);
return(null);
}
var variableName = (index < parameterCount) ? function.Parameters.ElementAt(index).Name : "...";
assignedParameter = new AssignmentExpression(new VariableExpression(variableName), parameter);
var value = GetParameter(parameterScope, scope, assignedParameter);
error = value as ParseErrorExpression;
if (error != null)
{
return(null);
}
if (index < parameterCount)
{
providedParameters.Remove(variableName);
parameterScope.DefineVariable(new VariableDefinitionExpression(variableName), value);
}
else
{
varargs.Entries.Add(value);
}
}
++index;
}
foreach (var parameter in providedParameters)
{
ExpressionBase value;
if (!function.DefaultParameters.TryGetValue(parameter, out value))
{
error = new ParseErrorExpression(String.Format("Required parameter '{0}' not provided", parameter), FunctionName);
return(null);
}
var assignmentScope = new InterpreterScope(scope)
{
Context = new AssignmentExpression(new VariableExpression(parameter), value)
};
if (!value.ReplaceVariables(assignmentScope, out value))
{
error = new ParseErrorExpression(value, this);
return(null);
}
parameterScope.DefineVariable(new VariableDefinitionExpression(parameter), value);
}
error = null;
return(parameterScope);
}
/// <summary>
/// Adds the function definition.
/// </summary>
public void AddFunction(FunctionDefinitionExpression function)
{
_functions[function.Name.Name] = function;
}
/// <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);
}
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 '(':
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':
if (tokenizer.Match("0x"))
{
string hexNumber = "";
while (Char.IsDigit(tokenizer.NextChar) || (tokenizer.NextChar >= 'A' && tokenizer.NextChar <= 'F') || (tokenizer.NextChar >= 'a' && tokenizer.NextChar <= 'f'))
{
hexNumber += tokenizer.NextChar;
tokenizer.Advance();
}
int hexValue = 0;
Int32.TryParse(hexNumber, System.Globalization.NumberStyles.HexNumber, System.Globalization.CultureInfo.CurrentCulture, out hexValue);
return(new IntegerConstantExpression(hexValue));
}
goto case '1';
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
{
var number = tokenizer.ReadNumber();
uint value;
UInt32.TryParse(number.ToString(), out value);
return(new IntegerConstantExpression((int)value));
}
case '-':
tokenizer.Advance();
if (tokenizer.NextChar >= '0' && tokenizer.NextChar <= '9')
{
if (tokenizer.Match("0x"))
{
string hexNumber = "";
while (Char.IsDigit(tokenizer.NextChar) || (tokenizer.NextChar >= 'A' && tokenizer.NextChar <= 'F') || (tokenizer.NextChar >= 'a' && tokenizer.NextChar <= 'f'))
{
hexNumber += tokenizer.NextChar;
tokenizer.Advance();
}
int hexValue = 0;
Int32.TryParse(hexNumber, System.Globalization.NumberStyles.HexNumber, System.Globalization.CultureInfo.CurrentCulture, out hexValue);
return(new IntegerConstantExpression(-hexValue));
}
var number = tokenizer.ReadNumber();
int value;
Int32.TryParse(number.ToString(), out value);
return(new IntegerConstantExpression(-value));
}
return(ParseError(tokenizer, "Minus without value"));
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(FunctionDefinitionExpression.Parse(tokenizer, line, column));
}
if (identifier == "for")
{
return(ForExpression.Parse(tokenizer, line, column));
}
if (identifier == "if")
{
return(IfExpression.Parse(tokenizer, line, column));
}
if (tokenizer.NextChar == '(')
{
tokenizer.Advance();
var parameters = new List <ExpressionBase>();
ParseParameters(tokenizer, parameters);
var functionCall = new FunctionCallExpression(new VariableExpression(identifier.ToString(), line, column), parameters);
functionCall.EndLine = tokenizer.Line;
functionCall.EndColumn = 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));
}
}