public static LNode unroll(LNode var, LNode cases, LNode body, IMessageSink sink)
{
if (!cases.Calls(S.Tuple) && !cases.Calls(S.Braces))
return Reject(sink, cases, "unroll: the right-hand side of 'in' should be a tuple");
// Maps identifiers => replacements. The integer counts how many times replacement occurred.
var replacements = InternalList<Triplet<Symbol, LNode, int>>.Empty;
if (var.IsId && !var.HasPAttrs()) {
replacements.Add(Pair.Create(var.Name, (LNode)LNode.Missing, 0));
} else {
var vars = var.Args;
if ((var.Calls(S.Tuple) || var.Calls(S.Braces)) && vars.All(a => a.IsId && !a.HasPAttrs())) {
replacements = new Triplet<Symbol, LNode, int>[vars.Count].AsInternalList();
for (int i = 0; i < vars.Count; i++) {
replacements.InternalArray[i].A = vars[i].Name;
// Check for duplicate names
for (int j = 0; j < i; j++)
if (replacements[i].A == replacements[j].A && replacements[i].A.Name != "_")
sink.Write(Severity.Error, vars[i], "unroll: duplicate name in the left-hand tuple"); // non-fatal
}
} else
return Reject(sink, cases, "unroll: the left-hand side of 'in' should be a simple identifier or a tuple of simple identifiers.");
}
UnrollCtx ctx = new UnrollCtx { Replacements = replacements };
WList<LNode> output = new WList<LNode>();
int iteration = 0;
foreach (LNode replacement in cases.Args)
{
iteration++;
bool tuple = replacement.Calls(S.Tuple) || replacement.Calls(S.Braces);
int count = tuple ? replacement.ArgCount : 1;
if (replacements.Count != count)
{
sink.Write(Severity.Error, replacement, "unroll, iteration {0}: Expected {1} replacement items, got {2}", iteration, replacements.Count, count);
if (count < replacements.Count)
continue; // too few
}
for (int i = 0; i < replacements.Count; i++)
replacements.InternalArray[i].B = tuple ? replacement.Args[i] : replacement;
if (body.Calls(S.Braces)) {
foreach (LNode stmt in body.Args)
output.Add(ctx.Replace(stmt).Value);
} else
output.Add(ctx.Replace(body).Value);
}
foreach (var r in replacements)
if (r.C == 0 && !r.A.Name.StartsWith("_"))
sink.Write(Severity.Warning, var, "Replacement variable '{0}' was never used", r.A);
return body.With(S.Splice, output.ToVList());
}
public static LNode unroll(LNode var, VList <LNode> cases, LNode body, IMessageSink sink)
{
// Maps identifiers => replacements. The integer counts how many times replacement occurred.
var replacements = InternalList <Triplet <Symbol, LNode, int> > .Empty;
if (var.IsId && !var.HasPAttrs())
{
replacements.Add(Pair.Create(var.Name, (LNode)LNode.Missing, 0));
}
else
{
var vars = var.Args;
if ((var.Calls(S.Tuple) || var.Calls(S.Braces)) && vars.All(a => a.IsId && !a.HasPAttrs()))
{
replacements = new Triplet <Symbol, LNode, int> [vars.Count].AsInternalList();
for (int i = 0; i < vars.Count; i++)
{
replacements.InternalArray[i].A = vars[i].Name;
// Check for duplicate names
for (int j = 0; j < i; j++)
{
if (replacements[i].A == replacements[j].A && replacements[i].A.Name != "_")
{
sink.Error(vars[i], "Duplicate name in the left-hand tuple"); // non-fatal
}
}
}
}
else
{
return(Reject(sink, var, "The left-hand side of 'in' should be a simple identifier or a tuple of simple identifiers."));
}
}
UnrollCtx ctx = new UnrollCtx {
Replacements = replacements
};
WList <LNode> output = new WList <LNode>();
int iteration = 0;
foreach (LNode replacement in cases)
{
iteration++;
bool tuple = replacement.Calls(S.Tuple) || replacement.Calls(S.Braces);
int count = tuple ? replacement.ArgCount : 1;
if (replacements.Count != count)
{
sink.Error(replacement, "iteration {0}: Expected {1} replacement items, got {2}", iteration, replacements.Count, count);
if (count < replacements.Count)
{
continue; // too few
}
}
for (int i = 0; i < replacements.Count; i++)
{
replacements.InternalArray[i].B = tuple ? replacement.Args[i] : replacement;
}
if (body.Calls(S.Braces))
{
foreach (LNode stmt in body.Args)
{
output.Add(ctx.Replace(stmt).Value);
}
}
else
{
output.Add(ctx.Replace(body).Value);
}
}
foreach (var r in replacements)
{
if (r.C == 0 && !r.A.Name.StartsWith("_"))
{
sink.Write(Severity.Warning, var, "Replacement variable '{0}' was never used", r.A);
}
}
return(body.With(S.Splice, output.ToVList()));
}