public AstMacroQuote(PegAstNode node)
: base(node)
{
CheckLabel(AstLabel.MacroQuote);
foreach (PegAstNode child in node.GetChildren())
{
AstMacroTerm term = Create(child) as AstMacroTerm;
if (term == null)
{
throw new Exception("internal grammar error: macro quotations can only contain macro terms");
}
mTerms.Add(term);
}
}
public AstMacroPattern(PegAstNode node)
: base(node)
{
CheckLabel(AstLabel.MacroPattern);
foreach (PegAstNode child in node.GetChildren())
{
AstMacroTerm tmp = CatAstNode.Create(child) as AstMacroTerm;
if (tmp == null)
{
throw new Exception("invalid grammar: only macro terms can be children of an ast macro mPattern");
}
mPattern.Add(tmp);
}
}
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 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);
}
