static void ExpandInline(CatExpr fxns, PushFunction q, int nMaxDepth)
{
CatExpr tmp = new CatExpr();
foreach (Function f in q.GetChildren())
{
ExpandInline(tmp, f, nMaxDepth - 1);
}
fxns.Add(new PushFunction(tmp));
}
public CatExpr NodesToFxns(string name, List <CatAstNode> nodes)
{
CatExpr result = new CatExpr();
for (int i = 0; i < nodes.Count; ++i)
{
CatAstNode node = nodes[i];
if (node.GetLabel().Equals(AstLabel.Name))
{
string s = node.ToString();
if (s.Equals(name))
{
result.Add(new SelfFunction(name));
}
else
{
result.Add(ThrowingLookup(s));
}
}
else if (node is AstLiteral)
{
result.Add(LiteralToFunction(name, node as AstLiteral));
}
else if (node is AstDef)
{
MakeFunction(node as AstDef);
}
else if (node is AstMacro)
{
MetaCat.AddMacro(node as AstMacro);
}
else
{
throw new Exception("unable to convert node to function: " + node.ToString());
}
}
return(result);
}
static void ExpandInline(CatExpr list, Function f, int nMaxDepth)
{
if (nMaxDepth == 0)
{
list.Add(f);
}
else if (f is PushFunction)
{
ExpandInline(list, f as PushFunction, nMaxDepth);
}
else if (f is QuotedFunction)
{
ExpandInline(list, f as QuotedFunction, nMaxDepth);
}
else if (f is DefinedFunction)
{
ExpandInline(list, f as DefinedFunction, nMaxDepth);
}
else
{
list.Add(f);
}
}
public CatExpr PatternToFxns(INameLookup names, List <AstMacroTerm> pattern)
{
CatExpr ret = new CatExpr();
foreach (AstMacroTerm t in pattern)
{
if (t is AstMacroTypeVar)
{
string s = t.ToString();
if (!mCapturedVars.ContainsKey(s))
{
throw new Exception("macro variable " + s + " was not captured");
}
CatExpr expr = mCapturedVars[s];
ret.AddRange(expr);
}
else if (t is AstMacroStackVar)
{
string s = (t as AstMacroStackVar).msName;
if (!mCapturedVars.ContainsKey(s))
{
throw new Exception("macro variable " + s + " was not captured");
}
CatExpr expr = mCapturedVars[s];
ret.AddRange(expr);
}
else if (t is AstMacroName)
{
string s = t.ToString();
if (s.Length < 1)
{
throw new Exception("internal error: macro name is empty string");
}
Function f = names.ThrowingLookup(s);
if (f == null)
{
if (Char.IsDigit(s[0]))
{
f = new PushInt(int.Parse(s));
}
else
{
throw new Exception("Could not find function " + s);
}
}
ret.Add(f);
}
else if (t is AstMacroQuote)
{
// TODO: handle typed terms within a quotation.
AstMacroQuote macroQuote = t as AstMacroQuote;
List <AstMacroTerm> localPattern = macroQuote.mTerms;
PushFunction q = new PushFunction(PatternToFxns(names, localPattern));
ret.Add(q);
}
else
{
throw new Exception("unrecognized macro term " + t.ToString());
}
}
return(ret);
}
/// <summary>
/// We attempt to execute an expression (list of functions) on an empty stack.
/// When no exception is raised we know that the subexpression can be replaced with anything
/// that generates the values.
/// </summary>
static CatExpr PartialEval(Executor exec, CatExpr fxns)
{
// Recursively partially evaluate all quotations
for (int i = 0; i < fxns.Count; ++i)
{
Function f = fxns[i];
if (f is PushFunction)
{
PushFunction q = f as PushFunction;
CatExpr tmp = PartialEval(new Executor(), q.GetSubFxns());
fxns[i] = new PushFunction(tmp);
}
}
CatExpr ret = new CatExpr();
object[] values = null;
int j = 0;
while (j < fxns.Count)
{
try {
Function f = fxns[j];
if (f is DefinedFunction)
{
f.Eval(exec);
}
else
{
if (f.GetFxnType() == null)
{
throw new Exception("no type availables");
}
if (f.GetFxnType().HasSideEffects())
{
throw new Exception("can't perform partial execution when an expression has side-effects");
}
f.Eval(exec);
}
// at each step, we have to get the values stored so far
// since they could keep changing and any exception
// will obliterate the old values.
values = exec.GetStackAsArray();
} catch {
if (values != null)
{
// Copy all of the values from the previous good execution
for (int k = values.Length - 1; k >= 0; --k)
{
ret.Add(ValueToFunction(values[k]));
}
}
ret.Add(fxns[j]);
exec.Clear();
values = null;
}
j++;
}
if (values != null)
{
for (int l = values.Length - 1; l >= 0; --l)
{
ret.Add(ValueToFunction(values[l]));
}
}
return(ret);
}
