public static void GenerateCode(Command command, GeneratorContext builder)
{
string label = null;
switch (command.Keyword)
{
case Keywords.End:
// End keywords were used to make the tree. They exist as
// statements beyond that only so that the tree (and editor
// functions that depend on the tree) are aware of them.
return;
case Keywords.Break:
if (builder.BreakLabels.Count == 0)
{
builder.ThrowError("Encountered break statement outside of loop");
}
label = builder.BreakLabels.Peek();
break;
case Keywords.Continue:
if (builder.ContinueLabels.Count == 0)
{
builder.ThrowError("Encountered continue statement outside of loop");
}
label = builder.ContinueLabels.Peek();
break;
default:
builder.ThrowError("Encountered unexpected command expression");
break;
}
if (label == null)
{
throw new Exception("Missing label");
}
Header ancestor = command.ParentBlockHint.Header;
while (true)
{
// There might be intermediate if blocks that have scopes that
// need ending. Also, the loop iteration we are breaking/skipping
// might have one too.
if (ancestor.RequiresScopeHint)
{
builder.AddOp(new ScopeEnd(), command.Token);
}
if (ancestor is LoopHeader loopHeader)
{
if (command.Keyword == Keywords.Continue &&
loopHeader.IsRange)
{
// For from-to loops, the increment is done at the end
// of the loop, and needs to be done here too. (loop-in
// loops do the incrementing at the beginning)
builder.AddOp(new Increment(loopHeader.IndexNameHint),
command.Token);
}
break;
}
// The parent of a header is the block it is a header of
// (confusing, when one puts it that way)
// So to get the parent block of the current block we need
// the parent of the parent
ancestor = command.ParentBlockHint.ParentBlockHint?.Header;
}
if (ancestor == null)
{
throw new Exception("Unable to locate continue command loop header");
}
builder.AddOp(new JumpLabel(label), command.Token);
}