public override bool Unify(BaseTerm t, VarStack varStack)
{
if (t is Variable)
{
return(t.Unify(this, varStack));
}
NextUnifyCount();
const double eps = 1.0e-6; // arbitrary, cosmetic
if (t is DecimalTerm)
{
return(Math.Abs(im) < eps &&
Math.Abs(re - ((DecimalTerm)t).ValueD) < eps);
}
if (t is ComplexTerm)
{
return(Math.Abs(re - ((ComplexTerm)t).Re) < eps &&
Math.Abs(im - ((ComplexTerm)t).Im) < eps);
}
//if (t is ComplexTerm)
// return ( re == ((ComplexTerm)t).Re && im == ((ComplexTerm)t).Im );
return(false);
}
public static bool SetWorkingDirectory(BaseTerm term, VarStack varStack)
{
if (term.Arity == 0)
{
workingDirectory = GetConfigSetting("WorkingDirectory", null);
IO.Message("Working directory set to '{0}'", WorkingDirectory);
return(true);
}
BaseTerm t0 = term.Arg(0);
if (t0.IsVar)
{
t0.Unify(new StringTerm(workingDirectory), varStack); // symbolic names
return(true);
}
string wd = Utils.DirectoryNameFromTerm(t0);
if (wd == null)
{
IO.Error("Illegal name '{0}' for working directory", t0.FunctorToString);
return(false);
}
workingDirectory = wd;
IO.Message("Working directory set to '{0}'", WorkingDirectory);
return(true);
}
// try to bind the variable associated with the list of search alternatives
// (t1|t2|...|tn) to the target term found matching one of these alternatives
bool TryBindingAltListVarToMatch(BaseTerm AltListVar, BaseTerm searchTerm, VarStack varStack)
{
if (AltListVar == null)
{
return(true);
}
return(AltListVar.Unify(searchTerm, varStack));
}
private AltLoopStatus TryOneAlternative(int ip, VarStack varStack, ListPatternElem e, int k,
int marker, ListTerm RangeList, int i, BaseTerm t, ref bool negSearchSucceeded, BaseTerm searchTerm)
{
bool unified = searchTerm.Unify(t, varStack);
if (e.IsNegSearch) // none of the terms in the inner loop may match. ~(a | b | c) = ~a & ~b & ~c
{
if (unified) // ... no point in investigating the other alternatives if one does
{
negSearchSucceeded = false;
return(AltLoopStatus.Break); // don't try the other alternatives
}
return(AltLoopStatus.TryNextDown); // non of the downranges matches may lead to a success
}
else
{
if (unified && // we found a match. Unify, and
TryBindingAltListVarToMatch(e.AltListBindVar, t, varStack) && // bind the AltListBindVar to the match
TryBindingRangeRelatedVars(e, i, RangeList, varStack)) // bind the range to the range variables
{
if (ip == pattern.Length - 1) // this was the last pattern element
{
if (k == target.Count - 1) // both pattern and target exhausted
{
return(AltLoopStatus.MatchFound);
}
}
else if (UnifyTailEx(ip + 1, k + 1, varStack)) // now deal with the rest
{
return(AltLoopStatus.MatchFound);
}
}
// if we arrive here, it was not possible to ...
// (1) ... unify the range's SearchTerm with the target element, or
// (2) ... unify the range variable with the range list, or
// (3) ... successfully process the rest of the pattern and target
// Now unbind and try matching with the next target element
BaseTerm.UnbindToMarker(varStack, marker);
return(AltLoopStatus.TryNextDown); // try the next downrange match
}
}
// try to bind the variable associated with the last of search alternatives
// (t1|t2|...|tn) to the target term found matching one of these alternatives
bool TryBindingAltListVarToMatch (BaseTerm AltListVar, BaseTerm searchTerm, VarStack varStack)
{
if (AltListVar == null) return true;
return AltListVar.Unify (searchTerm, varStack);
}
private AltLoopStatus TryOneAlternative (int ip, VarStack varStack, ListPatternElem e, int k,
int marker, ListTerm RangeList, int i, BaseTerm t, ref bool negSearchSucceeded, BaseTerm searchTerm)
{
bool unified = searchTerm.Unify (t, varStack);
if (e.IsNegSearch) // none of the terms in the inner loop may match. ~(a | b | c) = ~a & ~b & ~c
{
if (unified) // ... no point in investigating the other alternatives if one does
{
negSearchSucceeded = false;
return AltLoopStatus.Break; // don't try the other alternatives
}
return AltLoopStatus.TryNextDown; // non of the downranges matches may lead to a success
}
else
{
if (unified && // we found a match. Unify, and
TryBindingAltListVarToMatch (e.AltListBindVar, t, varStack) && // bind the AltListBindVar to the match
TryBindingRangeRelatedVars (e, i, RangeList, varStack)) // bind the range to the range variables
{
if (ip == pattern.Length - 1) // this was the last pattern element
{
if (k == target.Count - 1) // both pattern and target exhausted
return AltLoopStatus.MatchFound;
}
else if (UnifyTailEx (ip + 1, k + 1, varStack)) // now deal with the rest
return AltLoopStatus.MatchFound;
}
// if we arrive here, it was not possible to ...
// (1) ... unify the range's SearchTerm with the target element, or
// (2) ... unify the range variable with the range last, or
// (3) ... successfully process the rest of the pattern and target
// Now unbind and try matching with the next target element
BaseTerm.UnbindToMarker (varStack, marker);
return AltLoopStatus.TryNextDown; // try the next downrange match
}
}