private IEnumerable <IRFunctionSignatureHelp> GetSignaturesAsync(RFunctionSignatureInfo signatureInfo, IRIntellisenseContext context, Action <IEnumerable <IRFunctionSignatureHelp> > callback)
{
var snapshot = context.EditorBuffer.CurrentSnapshot;
var position = Math.Min(Math.Min(signatureInfo.FunctionCall.SignatureEnd, context.Position), snapshot.Length);
var applicableToSpan = GetApplicableSpan(signatureInfo, context);
IFunctionInfo functionInfo = null;
string packageName = null;
// First try user-defined function
if (string.IsNullOrEmpty(signatureInfo.PackageName))
{
functionInfo = context.AstRoot.GetUserFunctionInfo(signatureInfo.FunctionName, position);
}
else
{
packageName = signatureInfo.PackageName;
}
if (functionInfo != null)
{
return(MakeSignatures(functionInfo, applicableToSpan, context));
}
if (callback != null)
{
// Get collection of function signatures from documentation (parsed RD file)
_functionIndex.GetFunctionInfoAsync(signatureInfo.FunctionName, packageName, (fi, o) => {
InvokeSignaturesCallback(fi, applicableToSpan, context, callback);
});
}
return(null);
}
private ITrackingTextRange GetApplicableSpan(RFunctionSignatureInfo signatureInfo, IRIntellisenseContext context)
{
var snapshot = context.EditorBuffer.CurrentSnapshot;
var start = signatureInfo.FunctionCall.OpenBrace.End;
var end = Math.Min(signatureInfo.FunctionCall.SignatureEnd, snapshot.Length);
return(snapshot.CreateTrackingRange(TextRange.FromBounds(start, end)));
}