public static LoopHeader Loop(MatchIterator iterator)
{
Expression array;
iterator.AssertKeyword(Keywords.Loop);
Token loop = (Token)iterator.Current;
if (iterator.AtEnd())
{
LoopHeader result = new LoopHeader(loop);
return(result);
}
iterator.AssertExpression(out Expression firstExpression);
if (iterator.AtEnd())
{
// Actually checking that this expression is an array is for
// a later step, when the messenger is available.
array = firstExpression;
LoopHeader result = new LoopHeader(loop, array);
return(result);
}
if (iterator.NextIsKeyword(Keywords.In, out Token inToken))
{
// Again, actually checking that this is indeed just a name
// has to wait for a later stage.
Expression name = firstExpression;
iterator.AssertExpression(out array);
iterator.AssertEnd();
LoopHeader result = new LoopHeader(loop, name, inToken, array);
return(result);
}
if (iterator.NextIsKeyword(Keywords.From, out Token from))
{
Expression name = firstExpression;
iterator.AssertExpression(out Expression start);
iterator.AssertKeyword(Keywords.To, out Token to);
iterator.AssertExpression(out Expression end);
iterator.AssertEnd();
LoopHeader result = new LoopHeader(
loop, name, from, start, to, end);
return(result);
}
throw iterator.UnexpectedEnd();
}
private Color GetColor(SprakExpression item)
{
return(item switch
{
Block block => GetColor(block.Header),
Command _ => Colors.Blue,
FunctionCall _ => Colors.Orange,
FunctionHeader _ => Colors.Blue,
IfHeader _ => Colors.DarkRed,
LiteralArrayGet _ => Colors.Yellow,
LiteralGet _ => Colors.Yellow,
LoopHeader _ => Colors.Red,
MainHeader _ => Colors.Orange,
OperatorCall _ => Colors.Green,
Return _ => Colors.Blue,
VariableAssignment _ => Colors.Orange,
VariableReference _ => Colors.Yellow,
_ => Colors.Black
});
public static void GenerateCode(LoopHeader header, GeneratorContext builder)
{
bool requiresOuterScope = !header.IsInfinite;
bool requiresInnerScope = header.RequiresScopeHint;
if (requiresOuterScope)
{
builder.AddOp(new ScopeBegin(), header.LoopToken);
}
string endLabel = builder.DeclareLabel("LoopEnd");
builder.BreakLabels.Push(endLabel);
string continueLabel = builder.DeclareLabel("LoopContinue");
builder.ContinueLabels.Push(continueLabel);
string indexName = null;
if (header.IsInfinite)
{
builder.SetLabelToNext(continueLabel);
}
else if (header.IsRange)
{
builder.PushIndex();
indexName = header.Name;
// For the end expression, don't use a variable if a literal could be used instead
// Actually, it would be better if this were generalized to statements that translate to a single
// op, but that is an optimization for another day.
Op endOp;
if (header.RangeEnd is LiteralGet end)
{
endOp = new LiteralValue(end.Value);
}
else
{
string endName = builder.GetIndexedName("end");
builder.AddCode(header.RangeEnd);
builder.AddOp(new VariableCreate(endName), header.LoopToken);
endOp = new VariableGet(endName);
}
builder.AddCode(header.RangeStart);
builder.AddOp(new VariableCreate(indexName), header.NameToken);
builder.SetLabelToNext(continueLabel);
builder.AddOp(new VariableGet(indexName), header.NameToken);
builder.AddOp(endOp);
builder.AddOp(new GreaterThan(), header.FromToken);
builder.AddOp(new JumpLabelConditional(endLabel), header.FromToken);
}
else
{
builder.PushIndex();
indexName = builder.GetIndexedName("index");
string arrayName = builder.GetIndexedName("array");
string countName = builder.GetIndexedName("count");
string currentName = header.Name ?? "@";
builder.AddCode(header.Array);
builder.AddOp(new VariableCreate(arrayName), header.LoopToken);
builder.AddOp(new ArrayCount(arrayName), header.LoopToken);
builder.AddOp(new VariableCreate(countName), header.LoopToken);
builder.AddOp(new LiteralValue(new SprakNumber(0)), header.LoopToken);
builder.AddOp(new VariableCreate(indexName), header.LoopToken);
builder.AddOp(new LiteralValue(SprakUnit.Value), header.LoopToken);
builder.AddOp(new VariableCreate(currentName), header.LoopToken);
builder.SetLabelToNext(continueLabel);
builder.AddOp(new VariableGet(indexName), header.LoopToken);
builder.AddOp(new VariableGet(countName), header.LoopToken);
builder.AddOp(new GreaterThanOrEqualTo(), header.LoopToken);
builder.AddOp(new JumpLabelConditional(endLabel), header.LoopToken);
builder.AddOp(new VariableGet(arrayName), header.InToken);
builder.AddOp(new VariableGet(indexName), header.InToken);
builder.AddOp(new ArrayElementGet(), header.InToken);
builder.AddOp(new VariableSet(currentName), header.InToken);
builder.AddOp(new Increment(indexName), header.InToken);
};
// This is used by the continue command, currently.
header.IndexNameHint = indexName;
if (requiresInnerScope)
{
builder.AddOp(new ScopeBegin(), header.LoopToken);
}
foreach (Expression statement in header.ParentBlockHint.Statements)
{
builder.AddCode(statement);
}
if (requiresInnerScope)
{
builder.AddOp(new ScopeEnd(), header.EndToken);
}
if (header.IsRange)
{
builder.AddOp(new Increment(indexName), header.EndToken);
}
builder.AddOp(new JumpLabel(continueLabel), header.EndToken);
builder.SetLabelToNext(endLabel);
if (!header.IsInfinite)
{
builder.PopIndex();
}
if (requiresOuterScope)
{
builder.AddOp(new ScopeEnd(), header.EndToken);
}
builder.BreakLabels.Pop();
builder.ContinueLabels.Pop();
}
