TERM cont_ApplyBindingsModuloMatching(const CONTEXT Context, TERM Term,
BOOL VarCheck)
/**********************************************************
INPUT: A context, a term, and a boolean flag.
RETURNS: <Term> is destructively changed with respect to
established bindings in the context.
If <VarCheck> is true, all variables in <Term>
must be bound in the context. When compiled with
"CHECK" on, this condition is in fact checked.
This function only makes sense after a matching operation.
***********************************************************/
{
TERM RplacTerm;
LIST Arglist;
SYMBOL Top;
#ifdef CHECK
if (VarCheck && symbol_IsVariable(term_TopSymbol(Term)) &&
!cont_VarIsBound(Context, term_TopSymbol(Term))) {
misc_StartErrorReport();
misc_ErrorReport("\n In cont_ApplyBindingsModuloMatching:");
misc_ErrorReport(" Used in forbidden context.\n");
misc_FinishErrorReport();
}
#endif
Top = term_TopSymbol(Term);
if (symbol_IsVariable(Top)) {
if (cont_VarIsBound(Context, Top)) {
RplacTerm = cont_ContextBindingTerm(Context, Top);
Arglist = term_CopyTermList(term_ArgumentList(RplacTerm));
term_RplacTop(Term, term_TopSymbol(RplacTerm));
term_DeleteTermList(term_ArgumentList(Term));
term_RplacArgumentList(Term, Arglist);
}
}
else {
for (Arglist = term_ArgumentList(Term);
!list_Empty(Arglist);
Arglist = list_Cdr(Arglist))
cont_ApplyBindingsModuloMatching(Context, list_Car(Arglist), VarCheck);
}
return Term;
}
void symbol_Delete(SYMBOL Symbol)
/**************************************************************
INPUT: A symbol.
RETURNS: Nothing.
SUMMARY: Deletes the symbol from the symbol table and frees its memory.
***************************************************************/
{
#ifdef CHECK
if (!symbol_SignatureExists()) {
misc_StartErrorReport();
misc_ErrorReport("\n In symbol_Delete: Module was initialized without signature.\n");
misc_FinishErrorReport();
}
if (!symbol_IsSymbol(Symbol)) {
misc_StartErrorReport();
misc_ErrorReport("\n In symbol_Delete: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
if (!symbol_IsVariable(Symbol)) {
int Index;
SIGNATURE Entry;
Index = symbol_Index(Symbol);
symbol_FREEDSYMBOLS = list_Cons((POINTER)Index,symbol_FREEDSYMBOLS);
Entry = symbol_Signature(Index);
symbol_SetSignature(Index, NULL);
symbol_FreeSignature(Entry);
}
}
static __inline__ int table_Index(SYMBOL symbol)
{
if (symbol_IsVariable(symbol))
return -(int) symbol;
else
return symbol_Index(symbol);
}
TERM cont_ApplyBindingsModuloMatchingReverse(const CONTEXT Context, TERM Term)
/**********************************************************
INPUT: A term.
RETURNS: <Term> is destructively changed with respect to
established bindings in the leftmost context. This
function only make sense after a matching operation (reverse).
***********************************************************/
{
TERM RplacTerm;
LIST Arglist;
SYMBOL Top;
#ifdef CHECK
if (symbol_IsVariable(term_TopSymbol(Term)) &&
!cont_VarIsBound(Context, term_TopSymbol(Term))) {
misc_StartErrorReport();
misc_ErrorReport("\n In cont_ApplyBindingsModuloMatchingReverse:");
misc_ErrorReport(" Used in forbidden context.\n");
misc_FinishErrorReport();
}
#endif
Top = term_TopSymbol(Term);
if (symbol_IsVariable(Top)) {
if (cont_VarIsBound(Context, Top)) {
RplacTerm =
cont_CopyAndApplyIndexVariableBindings(Context,
cont_ContextBindingTerm(Context, Top));
term_RplacTop(Term, term_TopSymbol(RplacTerm));
term_DeleteTermList(term_ArgumentList(Term));
term_RplacArgumentList(Term, term_ArgumentList(RplacTerm));
term_Free(RplacTerm);
}
}
else {
for (Arglist = term_ArgumentList(Term); !list_Empty(Arglist);
Arglist = list_Cdr(Arglist))
cont_ApplyBindingsModuloMatchingReverse(Context, list_Car(Arglist));
}
return Term;
}
BOOL symbol_IsSymbol(SYMBOL Symbol)
/**************************************************************
INPUT: A symbol.
RETURNS: TRUE if the symbols is a variable or contained
in the symbol table.
***************************************************************/
{
return
(!symbol_SignatureExists() ||
((!symbol_Equal(Symbol, symbol__NULL)) &&
((symbol_IsVariable(Symbol) && Symbol<symbol_MaxVars()) ||
(symbol_IsSignature(Symbol) && symbol_Index(Symbol)<symbol_ACTINDEX))));
}
void symbol_FPrintOtter(FILE* File, SYMBOL Symbol)
/**************************************************************
INPUT: A file and a symbol.
RETURNS: None.
SUMMARY: Prints a symbol in Otter format to stdout.
***************************************************************/
{
#ifdef CHECK
if (!symbol_IsSymbol(Symbol)) {
misc_StartErrorReport();
misc_ErrorReport("\n In symbol_FPrintOtter: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
if (symbol_IsVariable(Symbol)) {
SYMBOL NormSymbol;
NormSymbol = symbol_NormVar(Symbol);
if (symbol_IsStandardVariable(Symbol)) {
if (Symbol <= 6)
/* u, v, w, x, y, z */
sprintf(symbol_VARSTRING,"%c", 116 + NormSymbol);
else
/* x1, x2, x3, ... */
sprintf(symbol_VARSTRING,"x%d", NormSymbol - 6);
}
else if (symbol_IsIndexVariable(Symbol))
/* I1, I2, I3, ... */
sprintf(symbol_VARSTRING,"I%d", NormSymbol);
fputs(symbol_VARSTRING, File);
}
else
if (symbol_SignatureExists()) {
if (symbol_IsConstant(Symbol))
fprintf(File, "c%s", symbol_Name(Symbol));
else
if (symbol_IsFunction(Symbol))
fprintf(File, "f%s", symbol_Name(Symbol));
else
if (symbol_IsPredicate(Symbol))
fprintf(File, "P%s", symbol_Name(Symbol));
else
fputs(symbol_Name(Symbol), File);
}
else
fprintf(File, "%d", Symbol);
}
BOOL cont_BindingsAreRenamingModuloMatching(const CONTEXT RenamingContext)
{
CONTEXT Context;
#ifdef CHECK
if (!cont_IsContextEmpty(RenamingContext)) {
misc_StartErrorReport();
misc_ErrorReport("\n In cont_BindingsAreRenamingModuloMatching:");
misc_ErrorReport(" Renaming context contains bindings.\n");
misc_FinishErrorReport();
}
#endif
cont_StartBinding();
Context = cont_LastBinding();
while (Context) {
if (!symbol_IsIndexVariable(cont_BindingSymbol(Context))) {
SYMBOL CodomainSymbol;
CodomainSymbol = term_TopSymbol(cont_BindingTerm(Context));
if (symbol_IsVariable(CodomainSymbol)) {
if (cont_VarIsRenamed(RenamingContext, CodomainSymbol)) {
cont_BackTrack();
return FALSE;
} else {
cont_CreateBinding(RenamingContext, CodomainSymbol, NULL, NULL);
cont_SetContextBindingRenaming(RenamingContext, CodomainSymbol, CodomainSymbol);
}
} else {
cont_BackTrack();
return FALSE;
}
}
Context = cont_BindingLink(Context);
}
cont_BackTrack();
return TRUE;
}
void symbol_FPrint(FILE* File, SYMBOL Symbol)
/**************************************************************
INPUT: A file and a symbol.
RETURNS: None.
SUMMARY: Prints a symbol to the file.
***************************************************************/
{
#ifdef CHECK
if (!symbol_IsSymbol(Symbol)) {
misc_StartErrorReport();
misc_ErrorReport("\n In symbol_FPrint: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
if (symbol_Equal(symbol_Null(),Symbol))
fputs("NULL", File);
else if (symbol_IsVariable(Symbol)) {
SYMBOL NormSymbol;
NormSymbol = symbol_NormVar(Symbol);
if (symbol_IsStandardVariable(Symbol)) {
if (Symbol <= 6)
/* U, V, W, X, Y, Z */
sprintf(symbol_VARSTRING,"%c", 'U' + NormSymbol - 1);
else
/* X1, X2, X3, ... */
sprintf(symbol_VARSTRING,"X%d", NormSymbol - 6);
}
else if (symbol_IsIndexVariable(Symbol))
/* I1, I2, I3, ... */
sprintf(symbol_VARSTRING,"I%d", NormSymbol);
fputs(symbol_VARSTRING, File);
}
else if (symbol_SignatureExists())
fputs(symbol_Name(Symbol), File);
else
fprintf(File, "%d", Symbol);
}
TERM cont_SymbolApplyBindings(CONTEXT TermContext, SYMBOL Symbol)
/**************************************************************
INPUT: A call-by-ref context and a variable symbol.
RETURNS: The recursively dereferenced term and the corresponding context,
NULL if the symbol is not bound
SUMMARY: Dereferences bindings of variables.
CAUTION: In general, the context of the returned term
is different to the input context.
***************************************************************/
{
TERM Term;
Term = (TERM)NULL;
while (symbol_IsVariable(Symbol)) {
if (cont_VarIsBound(TermContext, Symbol)) {
CONTEXT HelpContext;
HelpContext = cont_ContextBindingContext(TermContext, Symbol);
Term = cont_ContextBindingTerm(TermContext, Symbol);
TermContext = HelpContext;
Symbol = term_TopSymbol(Term);
} else
break;
}
if (Term != (TERM)NULL && term_IsComplex(Term)) {
LIST Scan, ArgumentList;
for (Scan = ArgumentList = list_Copy(term_ArgumentList(Term));
!list_Empty(Scan);
Scan = list_Cdr(Scan))
list_Rplaca(Scan, cont_CopyAndApplyBindings(TermContext, list_Car(Scan)));
return term_Create(term_TopSymbol(Term), ArgumentList);
}
return Term;
}
