public void Replace(INameLookup names, CatExpr fxns, List <AstMacroTerm> pattern)
{
CatExpr pNewFxns = PatternToFxns(names, pattern);
// For debugging purposes only
if (Config.gbShowRewritingRuleApplications)
{
string sFrom = "";
for (int i = mnFxnIndex; i < mnFxnIndex + mnFxnCount; ++i)
{
if (i > mnFxnIndex)
{
sFrom += " ";
}
sFrom += fxns[i].msName;
}
string sTo = "";
for (int i = 0; i < pNewFxns.Count; ++i)
{
if (i > 0)
{
sTo += " ";
}
sTo += pNewFxns[i].msName;
}
MainClass.WriteLine("Rewriting { " + sFrom + " } to { " + sTo + " }");
}
if (mnFxnIndex < fxns.Count)
{
fxns.RemoveRange(mnFxnIndex, mnFxnCount);
}
fxns.InsertRange(mnFxnIndex, pNewFxns);
}
public QuotedFunction(CatExpr children, CatFxnType pFxnType)
{
mSubFxns = new CatExpr(children.ToArray());
msDesc = "anonymous function";
msName = "_anonymous_";
mpFxnType = new CatQuotedType(pFxnType);
}
static public QuotedFunction ApplyMacros(INameLookup names, QuotedFunction f)
{
CatExpr list = new CatExpr(f.GetSubFxns().ToArray());
MetaCat.ApplyMacros(names, list);
return(new QuotedFunction(list));
}
public QuotedFunction(QuotedFunction first, QuotedFunction second)
{
mSubFxns = new CatExpr(first.GetSubFxns().ToArray());
mSubFxns.AddRange(second.GetSubFxns().ToArray());
msDesc = "anonymous composed function";
msName = "";
for (int i = 0; i < mSubFxns.Count; ++i)
{
if (i > 0)
{
msName += " ";
}
msName += mSubFxns[i].GetName();
}
try {
mpFxnType = new CatQuotedType(CatTypeReconstructor.ComposeTypes(first.GetFxnType(), second.GetFxnType()));
// TODO: remove once everythign tests okay.
//mpFxnType = new CatQuotedType(CatTypeReconstructor.ComposeTypes(first.GetUnquotedFxnType(), second.GetUnquotedFxnType()));
} catch (Exception e) {
Output.WriteLine("unable to type quotation: " + ToString());
Output.WriteLine("type error: " + e.Message);
mpFxnType = null;
}
}
static void ExpandInline(CatExpr fxns, DefinedFunction d, int nMaxDepth)
{
foreach (Function f in d.GetSubFxns())
{
ExpandInline(fxns, f, nMaxDepth - 1);
}
}
static public QuotedFunction ExpandInline(QuotedFunction f, int nMaxDepth)
{
CatExpr ret = new CatExpr();
ExpandInline(ret, f, nMaxDepth);
return(new QuotedFunction(ret));
}
static Node MakeNode(CatExpr expr)
{
Node ret = new Node();
ret.expr = expr;
return(ret);
}
public Function LiteralToFunction(string name, AstLiteral literal)
{
switch (literal.GetLabel())
{
case AstLabel.Int: {
AstInt tmp = literal as AstInt;
return(new PushInt(tmp.GetValue()));
}
case AstLabel.Bin: {
AstBin tmp = literal as AstBin;
return(new PushInt(tmp.GetValue()));
}
case AstLabel.Char: {
AstChar tmp = literal as AstChar;
return(new PushValue <char>(tmp.GetValue()));
}
case AstLabel.String: {
AstString tmp = literal as AstString;
return(new PushValue <string>(tmp.GetValue()));
}
case AstLabel.Float: {
AstFloat tmp = literal as AstFloat;
return(new PushValue <double>(tmp.GetValue()));
}
case AstLabel.Hex: {
AstHex tmp = literal as AstHex;
return(new PushInt(tmp.GetValue()));
}
case AstLabel.Quote: {
AstQuote tmp = literal as AstQuote;
CatExpr fxns = NodesToFxns(name, tmp.GetTerms());
if (Config.gbOptimizeQuotations)
{
MetaCat.ApplyMacros(this, fxns);
}
return(new PushFunction(fxns));
}
case AstLabel.Lambda: {
AstLambda tmp = literal as AstLambda;
CatLambdaConverter.Convert(tmp);
CatExpr fxns = NodesToFxns(name, tmp.GetTerms());
if (Config.gbOptimizeLambdas)
{
MetaCat.ApplyMacros(this, fxns);
}
return(new PushFunction(fxns));
}
default:
throw new Exception("unhandled literal " + literal.ToString());
}
}
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));
}
private static void ApplyMacrosInner(INameLookup names, CatExpr fxns)
{
// Recursively apply macros for all quotations.
for (int i = 0; i < fxns.Count; ++i)
{
if (fxns[i] is PushFunction)
{
PushFunction qf = fxns[i] as PushFunction;
CatExpr tmp = new CatExpr(qf.GetChildren());
ApplyMacros(names, tmp);
fxns[i] = new PushFunction(tmp);
}
}
// This could be done multiple time
List <MacroMatch> matches = new List <MacroMatch>();
// The peephole is the maximum size of the range of functions that we will consider
// for rewriting. This helps to reduces the overall complexity of the algorithm.
//int nPeephole = 20;
// This is the maximum size of the sub-expression that will be considered for matching.
int nMaxSubExpr = 10;
// Find matches
int nLastMatchPos = -1;
for (int nPos = 0; nPos < fxns.Count; ++nPos)
{
string s = fxns[nPos].msName;
if (mMacros.ContainsKey(s))
{
foreach (AstMacro m in mMacros[s])
{
MacroMatch match = MacroMatch.Create(m, fxns, nLastMatchPos, nPos, nMaxSubExpr);
if (match != null)
{
nLastMatchPos = nPos;
matches.Add(match);
}
}
}
}
// Replace matches
for (int i = matches.Count - 1; i >= 0; --i)
{
MacroMatch m = matches[i];
List <AstMacroTerm> pattern = m.mMacro.mDest.mPattern;
m.Replace(names, fxns, pattern);
}
}
private void ReplaceSelfFunctions(CatExpr fxns)
{
for (int i = 0; i < fxns.Count; ++i)
{
Function f = fxns[i];
if (f is SelfFunction)
{
fxns[i] = this;
}
if (f is PushFunction)
{
ReplaceSelfFunctions((f as PushFunction).GetChildren());
}
}
}
/// <summary>
/// This function is optimized to handle tail-calls with increasing the stack size.
/// </summary>
/// <param name="fxns"></param>
public void Execute(CatExpr fxns)
{
int i = 0;
while (i < fxns.Count)
{
Function f = fxns[i];
// Check if this is a tail call
// if so then we are going to avoid creating a new stack frame
if (i == fxns.Count - 1 && f.GetSubFxns() != null)
{
Trace("tail-call of '" + f.GetName() + "' function");
fxns = f.GetSubFxns();
i = 0;
}
else if (i == fxns.Count - 1 && f is Primitives.If)
{
Trace("tail-call of 'if' function");
QuotedFunction onfalse = PopFxn();
QuotedFunction ontrue = PopFxn();
if (PopBool())
{
fxns = ontrue.GetSubFxns();
}
else
{
fxns = onfalse.GetSubFxns();
}
i = 0;
}
else if (i == fxns.Count - 1 && f is Primitives.ApplyFxn)
{
Trace("tail-call of 'apply' function");
QuotedFunction q = PopFxn();
fxns = q.GetSubFxns();
i = 0;
}
else
{
Trace(f.ToString());
f.Eval(this);
++i;
}
}
}
public static Function ValueToFunction(Object o)
{
if (o is Int32)
{
return(new PushInt((int)o));
}
else if (o is Double)
{
return(new PushValue <double>((double)o));
}
else if (o is String)
{
return(new PushValue <string>((string)o));
}
else if (o is Boolean)
{
bool b = (bool)o;
if (b)
{
return(new Primitives.True());
}
else
{
return(new Primitives.False());
}
}
else if (o is CatList)
{
return(new PushValue <CatList>(o as CatList));
}
else if (o is QuotedFunction)
{
QuotedFunction qf = o as QuotedFunction;
CatExpr fxns = qf.GetSubFxns();
PushFunction q = new PushFunction(fxns);
return(q);
}
else
{
throw new Exception("Partial evaluator does not yet handle objects of type " + o);
}
}
public void AddFunctions(CatExpr fxns)
{
mFunctions.AddRange(fxns);
msDesc = "";
if (Config.gbVerboseInference && Config.gbTypeChecking)
{
Output.WriteLine("");
Output.WriteLine("inferring type of " + msName);
Output.WriteLine("===");
}
try {
mpFxnType = CatTypeReconstructor.Infer(mFunctions);
} catch (Exception e) {
Output.WriteLine("type error in function " + msName);
Output.WriteLine(e.Message);
mpFxnType = null;
}
}
public PushFunction(CatExpr children)
{
mSubFxns = children.GetRange(0, children.Count);
msDesc = "pushes an anonymous function onto the stack";
msName = "_function_";
if (Config.gbTypeChecking)
{
if (Config.gbVerboseInference)
{
Output.WriteLine("inferring type of quoted function " + msName);
}
try
{
// Quotations can be unclear?
CatFxnType childType = CatTypeReconstructor.Infer(mSubFxns);
// Honestly this should never be true.
if (childType == null)
{
throw new Exception("unknown type error");
}
mpFxnType = new CatQuotedType(childType);
mpFxnType = CatVarRenamer.RenameVars(mpFxnType);
}
catch (Exception e)
{
Output.WriteLine("Could not type quotation: " + msName);
Output.WriteLine("Type error: " + e.Message);
mpFxnType = null;
}
}
else
{
mpFxnType = null;
}
}
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);
}
public Function MakeFunction(AstDef def)
{
bool bLambda = def.mParams.Count > 0 || def.mLocals.Count > 0;
if (bLambda)
{
CatLambdaConverter.Convert(def);
}
CatExpr fxns = NodesToFxns(def.mName, def.mTerms);
Function ret = new DefinedFunction(def.mName, fxns);
if (def.mpMetaData != null)
{
ret.SetMetaData(new CatMetaDataBlock(def.mpMetaData));
}
if (bLambda && Config.gbOptimizeLambdas)
{
MetaCat.ApplyMacros(this, fxns);
}
AddFunction(ret);
return(ret);
}
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 override bool Equals(object obj)
{
if (!(obj is CatExpr))
{
return(false);
}
CatExpr expr = obj as CatExpr;
if (expr.Count != this.Count)
{
return(false);
}
for (int i = 0; i < Count; ++i)
{
Function f = this[i];
Function g = expr[i];
if (!f.Equals(g))
{
return(false);
}
}
return(true);
}
public static void ApplyMacros(INameLookup names, CatExpr fxns)
{
if (Config.gbShowRewritingRuleApplications)
{
Output.Write("Before rewriting: ");
Output.WriteLine(fxns);
}
// repeat until a fix-point is reached (the algorithm converges)
bool bDone = false;
while (!bDone)
{
CatExpr original = fxns.Clone();
ApplyMacrosInner(names, fxns);
bDone = fxns.Equals(original);
}
if (Config.gbShowRewritingRuleApplications)
{
Output.Write("After rewriting: ");
Output.WriteLine(fxns);
}
}
public IEnumerator <Node> GetNodes(int cutAt)
{
if (cutAt < 0)
{
yield return(null);
}
if (cutAt >= expr.Count)
{
yield return(null);
}
CatExpr leftSubExpr = expr.GetRangeFromTo(0, cutAt);
CatExpr rightSubExpr = expr.GetRangeFromTo(cutAt + 1, expr.Count - 1);
Node leftNode = MakeNode(leftSubExpr);
Node rightNode = MakeNode(rightSubExpr);
foreach (Node node in leftNode.GetNodeIter())
{
yield return(Compose(leftNode, node));
}
foreach (Node node in rightNode.GetNodeIter())
{
yield return(Compose(node, rightNode));
}
}
public DefinedFunction(string s, CatExpr fxns)
{
msName = s;
AddFunctions(fxns);
ReplaceSelfFunctions(fxns);
}
public QuotedFunction()
{
mSubFxns = new CatExpr();
}
public QuotedFunction(CatExpr children)
: this(children, CatTypeReconstructor.Infer(children))
{
}
/// <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);
}
public static Node MakeNode(CatExpr expr)
{
return(CodeGraph.MakeNode(expr));
}
public bool DoesTokenMatch(AstMacroTerm tkn, CatExpr x, out bool bRecoverable)
{
bRecoverable = true;
if (tkn is AstMacroName)
{
bRecoverable = false;
if (x.Count != 1)
{
return(false);
}
Function f = x[0];
string sName = f.GetName();
return(sName == tkn.ToString());
}
else if (tkn is AstMacroTypeVar)
{
if (x.GetFxnType() == null)
{
return(false);
}
if (!CatFxnType.CompareFxnTypes(x.GetFxnType(), CatFxnType.PushSomethingType))
{
return(false);
}
mCapturedVars.Add(tkn.ToString(), x);
return(true);
}
else if (tkn is AstMacroQuote)
{
AstMacroQuote macroQuote = tkn as AstMacroQuote;
if (x.Count != 1)
{
return(false);
}
PushFunction quote = x[0] as PushFunction;
if (quote == null)
{
return(false);
}
for (int i = 0; i < macroQuote.mTerms.Count; ++i)
{
// Are we are at a stack variable in the matching pattern
// if so it must be the last token in the pattern
// e.g. [1 2 $A] is legal [1 $A 2] is not.
if (macroQuote.mTerms[i] is AstMacroStackVar)
{
if (i != macroQuote.mTerms.Count - 1)
{
throw new Exception("within a quotation, expression variables can only be used in the right-most postition");
}
AstMacroStackVar v = macroQuote.mTerms[0] as AstMacroStackVar;
CatExpr expr = quote.GetChildren().GetRangeFrom(i);
mCapturedVars.Add(v.msName, expr);
return(true);
}
else if (macroQuote.mTerms[i] is AstMacroName)
{
// Well this is just an ordinary name pattern
AstMacroName name = macroQuote.mTerms[i] as AstMacroName;
if (quote.GetChildren().Count <= i)
{
return(false);
}
Function f = quote.GetChildren()[i];
if (!f.GetName().Equals(name.ToString()))
{
return(false);
}
}
else
{
return(false);
}
}
// No stack variable was encountered in the pattern
// therefore the match must have been perfect, which means there are no
// more terms in the input
if (quote.GetChildren().Count != macroQuote.mTerms.Count)
{
return(false);
}
return(true);
}
else if (tkn is AstMacroStackVar)
{
AstMacroStackVar v = tkn as AstMacroStackVar;
if (v.mType == null)
{
return(false);
}
if (x.GetFxnType() == null)
{
return(false);
}
if (!CatFxnType.CompareFxnTypes(x.GetFxnType(), v.mType))
{
return(false);
}
mCapturedVars.Add(v.msName, x);
return(true);
}
else
{
throw new Exception("unrecognized macro term " + tkn.ToString());
}
}
static public MacroMatch Create(AstMacro m, CatExpr fxns, int nPrevMatchPos, int nFxnIndex, int nSubExprSize)
{
if (nFxnIndex < 0)
{
return(null);
}
if (nFxnIndex >= fxns.Count)
{
return(null);
}
List <AstMacroTerm> pattern = m.mSrc.mPattern;
MacroMatch match = new MacroMatch(m);
int nFirst = nFxnIndex;
int nLast = nFxnIndex;
int nTokenIndex = pattern.Count - 1;
// Start at the end of the pattern and move backwards comparing expressions
while (nFirst > nPrevMatchPos)
{
Trace.Assert(nTokenIndex <= pattern.Count);
Trace.Assert(nFirst >= 0);
Trace.Assert(nLast >= nFirst);
Trace.Assert(nTokenIndex < pattern.Count);
// get the current sub-expression that we are evaluating
CatExpr expr = fxns.GetRangeFromTo(nFirst, nLast);
AstMacroTerm tkn = pattern[nTokenIndex];
bool bRecoverable = false;
if (match.DoesTokenMatch(tkn, expr, out bRecoverable))
{
// Check if we have matched the whole pattern
if (nTokenIndex == 0)
{
match.mnFxnIndex = nFirst;
match.mnFxnCount = (nFxnIndex - nFirst) + 1;
return(match);
}
// Go to the previous token
nTokenIndex -= 1;
// Adjust the sub-expression range
nFirst -= 1;
nLast = nFirst;
}
else
{
// Some failed matches (such as identifier names) can not be recovered from.
if (!bRecoverable)
{
return(null);
}
// Widen the sub-expression.
nFirst -= 1;
// Check if we have passed the limit of how big of a
// sub-expression will be examined
if (nLast - nFirst > nSubExprSize)
{
return(null);
}
}
}
// The loop was finished and no match was found.
return(null);
}
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);
}
public CodeGraph(CatExpr expr)
{
root = MakeNode(expr);
}