/// <summary>
/// Returns a sequence of suggestions for replacing ranges over array indices with the corresponding library call,
/// provided the corresponding library is referenced.
/// Returns an empty enumerable if this is not the case or any of the given arguments is null.
/// </summary>
internal static IEnumerable <(string, WorkspaceEdit)> SuggestionsForIndexRange
(this FileContentManager file, CompilationUnit compilation, LSP.Range range)
{
if (file == null || compilation == null || range?.Start == null)
{
return(Enumerable.Empty <(string, WorkspaceEdit)>());
}
var indexRangeNamespaces = compilation.GlobalSymbols.NamespacesContainingCallable(BuiltIn.IndexRange.Name);
if (!indexRangeNamespaces.Contains(BuiltIn.IndexRange.Namespace))
{
return(Enumerable.Empty <(string, WorkspaceEdit)>());
}
var suggestedOpenDir = file.OpenDirectiveSuggestions(range.Start.Line, BuiltIn.IndexRange.Namespace);
/// Returns true the given expression is of the form "0 .. Length(args) - 1",
/// as well as the range of the entire expression and the argument tuple "(args)" as out parameters.
bool IsIndexRange(QsExpression iterExpr, Position offset, out LSP.Range exprRange, out LSP.Range argRange)
{
if (iterExpr.Expression is QsExpressionKind <QsExpression, QsSymbol, QsType> .RangeLiteral rangeExpression && iterExpr.Range.IsValue && // iterable expression is a valid range literal
rangeExpression.Item1.Expression is QsExpressionKind <QsExpression, QsSymbol, QsType> .IntLiteral intLiteralExpression && intLiteralExpression.Item == 0L && // .. starting at 0 ..
rangeExpression.Item2.Expression is QsExpressionKind <QsExpression, QsSymbol, QsType> .SUB SUBExpression && // .. and ending in subracting ..
SUBExpression.Item2.Expression is QsExpressionKind <QsExpression, QsSymbol, QsType> .IntLiteral subIntLiteralExpression && subIntLiteralExpression.Item == 1L && // .. 1 from ..
SUBExpression.Item1.Expression is QsExpressionKind <QsExpression, QsSymbol, QsType> .CallLikeExpression callLikeExression && // .. a call ..
callLikeExression.Item1.Expression is QsExpressionKind <QsExpression, QsSymbol, QsType> .Identifier identifier && // .. to and identifier ..
identifier.Item1.Symbol is QsSymbolKind <QsSymbol> .Symbol symName && symName.Item.Value == BuiltIn.Length.Name.Value && // .. "Length" called with ..
callLikeExression.Item2.Expression is QsExpressionKind <QsExpression, QsSymbol, QsType> .ValueTuple valueTuple && callLikeExression.Item2.Range.IsValue) // .. a valid argument tuple
{
exprRange = DiagnosticTools.GetAbsoluteRange(offset, iterExpr.Range.Item);
argRange = DiagnosticTools.GetAbsoluteRange(offset, callLikeExression.Item2.Range.Item);
return(true);
}
(exprRange, argRange) = (null, null);
return(false);
}
/// Returns the text edits for replacing an range over the indices with the corresponding library call if the given code fragment is a suitable for-loop intro.
/// The returned edits do *not* include an edit for adding the corresponding open-directive if necessary.
IEnumerable <TextEdit> IndexRangeEdits(CodeFragment fragment)
{
if (fragment.Kind is QsFragmentKind.ForLoopIntro forLoopIntro && // todo: in principle we could give these suggestions for any index range
IsIndexRange(forLoopIntro.Item2, fragment.GetRange().Start, out var iterExprRange, out var argTupleRange))
{
yield return(new TextEdit()
{
Range = new LSP.Range()
{
Start = iterExprRange.Start, End = argTupleRange.Start
},
NewText = BuiltIn.IndexRange.Name.Value
});
yield return(new TextEdit()
{
Range = new LSP.Range()
{
Start = argTupleRange.End, End = iterExprRange.End
},
NewText = ""
});
}
}
var fragments = file.FragmentsOverlappingWithRange(range);
var edits = fragments.SelectMany(IndexRangeEdits);
return(edits.Any()
? new[] { ("Use IndexRange to iterate over indices.", file.GetWorkspaceEdit(suggestedOpenDir.Concat(edits).ToArray())) }
