/// <summary>
/// Given expression statement determines if it defines a function
/// and if so, returns the function definition and the variable
/// it is assigned to.
/// </summary>
public static IFunctionDefinition GetVariableOrFunctionDefinition(this IExpressionStatement es, out Variable v) {
v = null;
if (es == null || es.Expression == null) {
return null;
}
// Tree:
// <-
// x function(a)
//
//
var c = es.Expression.Children;
if (c.Count == 1) {
var op = c[0] as IOperator;
if (op != null) {
if (op.OperatorType == OperatorType.LeftAssign || op.OperatorType == OperatorType.Equals) {
v = op.LeftOperand as Variable;
if (v != null) {
return op.RightOperand as IFunctionDefinition;
}
}
else if (op.OperatorType == OperatorType.RightAssign) {
v = op.RightOperand as Variable;
}
}
}
return null;
}
public override bool Parse(ParseContext context, IAstNode parent) {
TokenStream<RToken> tokens = context.Tokens;
if (tokens.CurrentToken.IsVariableKind()) {
var v = new Variable();
v.Parse(context, this);
// Variables don't set parent since during complex
// exression parsing parent is determined by the
// expression parser based on precedence and grouping.
v.Parent = this;
this.Variable = v;
if (tokens.CurrentToken.IsKeywordText(context.TextProvider, "in")) {
this.InOperator = new TokenNode();
this.InOperator.Parse(context, this);
this.Expression = new Expression(inGroup: true);
if (this.Expression.Parse(context, this)) {
return base.Parse(context, parent);
}
} else {
context.AddError(new MissingItemParseError(ParseErrorType.InKeywordExpected, tokens.CurrentToken));
}
} else {
context.AddError(new MissingItemParseError(ParseErrorType.IndentifierExpected, tokens.PreviousToken));
}
return false;
}
private static bool GetFunction(AstRoot astRoot, ref int position, out FunctionCall functionCall, out Variable functionVariable)
{
functionVariable = null;
functionCall = astRoot.GetNodeOfTypeFromPosition<FunctionCall>(position);
if (functionCall == null && position > 0)
{
// Retry in case caret is at the very end of function signature
// that does not have final close brace yet.
functionCall = astRoot.GetNodeOfTypeFromPosition<FunctionCall>(position - 1, includeEnd: true);
if(functionCall != null)
{
// But if signature does have closing brace and caret
// is beyond it, we are really otuside of the signature.
if(functionCall.CloseBrace != null && position >= functionCall.CloseBrace.End) {
return false;
}
if (position > functionCall.SignatureEnd) {
position = functionCall.SignatureEnd;
}
}
}
if (functionCall != null && functionCall.Children.Count > 0)
{
functionVariable = functionCall.Children[0] as Variable;
return functionVariable != null;
}
return false;
}
public static IFunctionDefinition FindFunctionDefinition(ITextBuffer textBuffer, AstRoot ast, int position, out Variable v) {
v = null;
var exp = ast.GetNodeOfTypeFromPosition<IExpressionStatement>(position);
return exp?.GetVariableOrFunctionDefinition(out v);
}
private OperationType HandleIdentifier(ParseContext context) {
Variable variable = new Variable();
variable.Parse(context, null);
_operands.Push(variable);
return OperationType.Operand;
}
