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());
}
}
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);
}