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65bcdc541c
yap-6.3/C/parser.c
Vítor Santos Costa 53877ad426 docs
2014-12-24 15:32:29 +00:00

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/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: parser.c *
* Last rev: *
* mods: *
* comments: Prolog's parser *
* *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "%W% %G%";
#endif
/**
@defgroup YAPSyntax YAP Syntax
@ingroup YAPProgramming
@{
We will describe the syntax of YAP at two levels. We first will
describe the syntax for Prolog terms. In a second level we describe
the \a tokens from which Prolog \a terms are
built.
@defgroup Formal_Syntax Syntax of Terms
@ingroup Syntax
@{
Below, we describe the syntax of YAP terms from the different
classes of tokens defined above. The formalism used will be <em>BNF</em>,
extended where necessary with attributes denoting integer precedence or
operator type.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
term ----> subterm(1200) end_of_term_marker
subterm(N) ----> term(M) [M <= N]
term(N) ----> op(N, fx) subterm(N-1)
| op(N, fy) subterm(N)
| subterm(N-1) op(N, xfx) subterm(N-1)
| subterm(N-1) op(N, xfy) subterm(N)
| subterm(N) op(N, yfx) subterm(N-1)
| subterm(N-1) op(N, xf)
| subterm(N) op(N, yf)
term(0) ----> atom '(' arguments ')'
| '(' subterm(1200) ')'
| '{' subterm(1200) '}'
| list
| string
| number
| atom
| variable
arguments ----> subterm(999)
| subterm(999) ',' arguments
list ----> '[]'
| '[' list_expr ']'
list_expr ----> subterm(999)
| subterm(999) list_tail
list_tail ----> ',' list_expr
| ',..' subterm(999)
| '|' subterm(999)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Notes:
+ \a op(N,T) denotes an atom which has been previously declared with type
\a T and base precedence \a N.
+ Since ',' is itself a pre-declared operator with type \a xfy and
precedence 1000, is \a subterm starts with a '(', \a op must be
followed by a space to avoid ambiguity with the case of a functor
followed by arguments, e.g.:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ (a,b) [the same as '+'(','(a,b)) of arity one]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
versus
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+(a,b) [the same as '+'(a,b) of arity two]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
In the first rule for term(0) no blank space should exist between
\a atom and '('.
+
Each term to be read by the YAP parser must end with a single
dot, followed by a blank (in the sense mentioned in the previous
paragraph). When a name consisting of a single dot could be taken for
the end of term marker, the ambiguity should be avoided by surrounding the
dot with single quotes.
@}
*/
/*
* Description:
*
* parser: produces a prolog term from an array of tokens
*
* parser usage: the parser takes its input from an array of token descriptions
* addressed by the global variable 'tokptr' and produces a Term as result. A
* macro 'NextToken' should be defined in 'yap.h' for advancing 'tokptr' from
* one token to the next. In the distributed version this macro also updates
* a variable named 'toktide' for keeping track of how far the parser went
* before failling with a syntax error. The parser should be invoked with
* 'tokptr' pointing to the first token. The last token should have type
* 'eot_tok'. The parser return either a Term. Syntactic errors are signaled
* by a return value 0. The parser builds new terms on the 'global stack' and
* also uses an auxiliary stack pointed to by 'AuxSp'. In the distributed
* version this auxiliary stack is assumed to grow downwards. This
* assumption, however, is only relevant to routine 'ParseArgs', and to the
* variable toktide. conclusion: set tokptr pointing to first token set AuxSp
* Call Parse
*
* VSC: Working whithout known bugs in 87/4/6
*
* LD: -I or +I evaluated by parser 87/4/28
*
* LD: parser extended 87/4/28
*
*/
#include "Yap.h"
#include "Yatom.h"
#include "YapHeap.h"
#include "yapio.h"
#include "eval.h"
/* stuff we want to use in standard YAP code */
#include "pl-shared.h"
#include "YapText.h"
#include "pl-read.h"
#include "pl-text.h"
#if HAVE_STRING_H
#include <string.h>
#endif
#ifdef __STDC__XXX
#define Volatile volatile
#else
#define Volatile
#endif
/* weak backtraking mechanism based on long_jump */
typedef struct jmp_buff_struct {
sigjmp_buf JmpBuff;
} JMPBUFF;
static void GNextToken( CACHE_TYPE1 );
static void checkfor(wchar_t, JMPBUFF * CACHE_TYPE);
static Term ParseArgs(read_data *, Atom, wchar_t, JMPBUFF *, Term CACHE_TYPE);
static Term ParseList(read_data *, JMPBUFF * CACHE_TYPE);
static Term ParseTerm(read_data *, int, JMPBUFF * CACHE_TYPE);
#define TRY(S,P) \
{ Volatile JMPBUFF *saveenv, newenv; \
Volatile TokEntry *saveT=LOCAL_tokptr; \
Volatile CELL *saveH=HR; \
Volatile int savecurprio=curprio; \
saveenv=FailBuff; \
if(!sigsetjmp(newenv.JmpBuff, 0)) { \
FailBuff = &newenv; \
S; \
FailBuff=saveenv; \
P; \
} \
else { FailBuff=saveenv; \
HR=saveH; \
curprio = savecurprio; \
LOCAL_tokptr=saveT; \
} \
}
#define TRY3(S,P,F) \
{ Volatile JMPBUFF *saveenv, newenv; \
Volatile TokEntry *saveT=LOCAL_tokptr; \
Volatile CELL *saveH=HR; \
saveenv=FailBuff; \
if(!sigsetjmp(newenv.JmpBuff, 0)) { \
FailBuff = &newenv; \
S; \
FailBuff=saveenv; \
P; \
} \
else { \
FailBuff=saveenv; \
HR=saveH; \
LOCAL_tokptr=saveT; \
F } \
}
#define FAIL siglongjmp(FailBuff->JmpBuff,1)
VarEntry *
Yap_LookupVar(char *var) /* lookup variable in variables table */
{
CACHE_REGS
VarEntry *p;
#if DEBUG
if (GLOBAL_Option[4])
fprintf(stderr,"[LookupVar %s]", var);
#endif
if (var[0] != '_' || var[1] != '\0') {
VarEntry **op = &LOCAL_VarTable;
unsigned char *vp = (unsigned char *)var;
UInt hv;
p = LOCAL_VarTable;
hv = HashFunction(vp) % AtomHashTableSize;
while (p != NULL) {
CELL hpv = p->hv;
if (hv == hpv) {
Int scmp;
if ((scmp = strcmp(var, p->VarRep)) == 0) {
p->refs++;
return(p);
} else if (scmp < 0) {
op = &(p->VarLeft);
p = p->VarLeft;
} else {
op = &(p->VarRight);
p = p->VarRight;
}
} else if (hv < hpv) {
op = &(p->VarLeft);
p = p->VarLeft;
} else {
op = &(p->VarRight);
p = p->VarRight;
}
}
p = (VarEntry *) Yap_AllocScannerMemory(strlen(var) + sizeof(VarEntry));
*op = p;
p->VarLeft = p->VarRight = NULL;
p->hv = hv;
p->refs = 1L;
strcpy(p->VarRep, var);
} else {
/* anon var */
p = (VarEntry *) Yap_AllocScannerMemory(sizeof(VarEntry) + 2);
p->VarLeft = LOCAL_AnonVarTable;
LOCAL_AnonVarTable = p;
p->VarRight = NULL;
p->refs = 0L;
p->hv = 1L;
p->VarRep[0] = '_';
p->VarRep[1] = '\0';
}
p->VarAdr = TermNil;
return (p);
}
static Term
VarNames(VarEntry *p,Term l USES_REGS)
{
if (p != NULL) {
if (strcmp(p->VarRep, "_") != 0) {
Term t[2];
Term o;
t[0] = MkAtomTerm(Yap_LookupAtom(p->VarRep));
t[1] = p->VarAdr;
o = Yap_MkApplTerm(FunctorEq, 2, t);
o = MkPairTerm(o, VarNames(p->VarRight,
VarNames(p->VarLeft,l PASS_REGS) PASS_REGS));
if (HR > ASP-4096) {
save_machine_regs();
siglongjmp(LOCAL_IOBotch,1);
}
return(o);
} else {
return VarNames(p->VarRight,VarNames(p->VarLeft,l PASS_REGS) PASS_REGS);
}
} else {
return (l);
}
}
Term
Yap_VarNames(VarEntry *p,Term l)
{
CACHE_REGS
return VarNames(p,l PASS_REGS);
}
static Term
Singletons(VarEntry *p,Term l USES_REGS)
{
if (p != NULL) {
if (p->VarRep && p->VarRep[0] != '_' && p->refs == 1) {
Term t[2];
Term o;
t[0] = MkAtomTerm(Yap_LookupAtom(p->VarRep));
t[1] = p->VarAdr;
o = Yap_MkApplTerm(FunctorEq, 2, t);
o = MkPairTerm(o, Singletons(p->VarRight,
Singletons(p->VarLeft,l PASS_REGS) PASS_REGS));
if (HR > ASP-4096) {
save_machine_regs();
siglongjmp(LOCAL_IOBotch,1);
}
return(o);
} else {
return Singletons(p->VarRight,Singletons(p->VarLeft,l PASS_REGS) PASS_REGS);
}
} else {
return (l);
}
}
Term
Yap_Singletons(VarEntry *p,Term l)
{
CACHE_REGS
return Singletons(p,l PASS_REGS);
}
static Term
Variables(VarEntry *p,Term l USES_REGS)
{
if (p != NULL) {
Term o;
o = MkPairTerm(p->VarAdr, Variables(p->VarRight,Variables(p->VarLeft,l PASS_REGS) PASS_REGS));
if (HR > ASP-4096) {
save_machine_regs();
siglongjmp(LOCAL_IOBotch,1);
}
return(o);
} else {
return (l);
}
}
Term
Yap_Variables(VarEntry *p,Term l)
{
CACHE_REGS
return Variables(p,l PASS_REGS);
}
static int
IsPrefixOp(Atom op,int *pptr, int *rpptr USES_REGS)
{
int p;
OpEntry *opp = Yap_GetOpProp(op, PREFIX_OP PASS_REGS);
if (!opp)
return FALSE;
if (opp->OpModule &&
opp->OpModule != CurrentModule) {
READ_UNLOCK(opp->OpRWLock);
return FALSE;
}
if ((p = opp->Prefix) != 0) {
READ_UNLOCK(opp->OpRWLock);
*pptr = *rpptr = p & MaskPrio;
if (p & DcrrpFlag)
--* rpptr;
return TRUE;
} else {
READ_UNLOCK(opp->OpRWLock);
return FALSE;
}
}
int
Yap_IsPrefixOp(Atom op,int *pptr, int *rpptr)
{
CACHE_REGS
return IsPrefixOp(op,pptr,rpptr PASS_REGS);
}
static int
IsInfixOp(Atom op, int *pptr, int *lpptr, int *rpptr USES_REGS)
{
int p;
OpEntry *opp = Yap_GetOpProp(op, INFIX_OP PASS_REGS);
if (!opp)
return FALSE;
if (opp->OpModule &&
opp->OpModule != CurrentModule) {
READ_UNLOCK(opp->OpRWLock);
return FALSE;
}
if ((p = opp->Infix) != 0) {
READ_UNLOCK(opp->OpRWLock);
*pptr = *rpptr = *lpptr = p & MaskPrio;
if (p & DcrrpFlag)
--* rpptr;
if (p & DcrlpFlag)
--* lpptr;
return TRUE;
} else {
READ_UNLOCK(opp->OpRWLock);
return FALSE;
}
}
int
Yap_IsInfixOp(Atom op, int *pptr, int *lpptr, int *rpptr)
{
CACHE_REGS
return IsInfixOp(op, pptr, lpptr, rpptr PASS_REGS);
}
static int
IsPosfixOp(Atom op, int *pptr, int *lpptr USES_REGS)
{
int p;
OpEntry *opp = Yap_GetOpProp(op, POSFIX_OP PASS_REGS);
if (!opp)
return FALSE;
if (opp->OpModule &&
opp->OpModule != CurrentModule) {
READ_UNLOCK(opp->OpRWLock);
return FALSE;
}
if ((p = opp->Posfix) != 0) {
READ_UNLOCK(opp->OpRWLock);
*pptr = *lpptr = p & MaskPrio;
if (p & DcrlpFlag)
--* lpptr;
return (TRUE);
} else {
READ_UNLOCK(opp->OpRWLock);
return (FALSE);
}
}
int
Yap_IsPosfixOp(Atom op, int *pptr, int *lpptr)
{
CACHE_REGS
return IsPosfixOp(op, pptr, lpptr PASS_REGS);
}
inline static void
GNextToken( USES_REGS1 )
{
if (LOCAL_tokptr->Tok == Ord(eot_tok))
return;
if (LOCAL_tokptr == LOCAL_toktide)
LOCAL_toktide = LOCAL_tokptr = LOCAL_tokptr->TokNext;
else
LOCAL_tokptr = LOCAL_tokptr->TokNext;
}
inline static void
checkfor(wchar_t c, JMPBUFF *FailBuff USES_REGS)
{
if (LOCAL_tokptr->Tok != Ord(Ponctuation_tok)
|| LOCAL_tokptr->TokInfo != (Term)c)
FAIL;
NextToken;
}
#ifdef O_QUASIQUOTATIONS
static int
is_quasi_quotation_syntax(Term goal, ReadData _PL_rd, Atom *pat)
{ CACHE_REGS
Term m = CurrentModule, t;
Atom at;
UInt arity;
Functor f;
t = Yap_StripModule(goal, &m);
f = FunctorOfTerm( t );
*pat = at = NameOfFunctor( f );
arity = ArityOfFunctor( f );
if ( arity > 0 )
return TRUE;
return FALSE;
}
static int
get_quasi_quotation(term_t t, unsigned char **here, unsigned char *ein,
ReadData _PL_rd)
{ unsigned char *in, *start = *here;
for(in=start; in <= ein; in++)
{ if ( in[0] == '}' &&
in[-1] == '|' )
{ *here = in+1; /* after } */
in--; /* Before | */
if ( _PL_rd->quasi_quotations ) /* option; must return strings */
{ PL_chars_t txt;
int rc;
txt.text.t = (char*)start;
txt.length = in-start;
txt.storage = PL_CHARS_HEAP;
txt.encoding = ENC_UTF8;
txt.canonical = FALSE;
rc = PL_unify_text(t, 0, &txt, PL_CODE_LIST);
PL_free_text(&txt);
return rc;
} else
{ return PL_unify_term(t, PL_FUNCTOR, FUNCTOR_dquasi_quotation3,
PL_POINTER, _PL_rd,
PL_INTPTR, (intptr_t)(start),
PL_INTPTR, (intptr_t)(in-start));
}
}
}
return FALSE; //errorWarning("end_of_file_in_quasi_quotation", 0, _PL_rd);
}
#endif /*O_QUASIQUOTATIONS*/
static Term
ParseArgs(read_data *rd, Atom a, wchar_t close, JMPBUFF *FailBuff, Term arg1 USES_REGS)
{
int nargs = 0;
Term *p, t;
Functor func;
#ifdef SFUNC
SFEntry *pe = (SFEntry *) Yap_GetAProp(a, SFProperty);
#endif
NextToken;
p = (Term *) ParserAuxSp;
if (arg1) {
*p = arg1;
nargs++;
ParserAuxSp = (char *)(p+1);
if (LOCAL_tokptr->Tok == Ord(Ponctuation_tok)
&& LOCAL_tokptr->TokInfo == close) {
func = Yap_MkFunctor(a, 1);
if (func == NULL) {
LOCAL_ErrorMessage = "Heap Overflow";
FAIL;
}
t = Yap_MkApplTerm(func, nargs, p);
if (HR > ASP-4096) {
LOCAL_ErrorMessage = "Stack Overflow";
return TermNil;
}
NextToken;
return t;
}
}
while (1) {
Term *tp = (Term *)ParserAuxSp;
if (ParserAuxSp+1 > LOCAL_TrailTop) {
LOCAL_ErrorMessage = "Trail Overflow";
FAIL;
}
*tp++ = Unsigned(ParseTerm(rd, 999, FailBuff PASS_REGS));
ParserAuxSp = (char *)tp;
++nargs;
if (LOCAL_tokptr->Tok != Ord(Ponctuation_tok))
break;
if (((int) LOCAL_tokptr->TokInfo) != ',')
break;
NextToken;
}
ParserAuxSp = (char *)p;
/*
* Needed because the arguments for the functor are placed in reverse
* order
*/
if (HR > ASP-(nargs+1)) {
LOCAL_ErrorMessage = "Stack Overflow";
FAIL;
}
func = Yap_MkFunctor(a, nargs);
if (func == NULL) {
LOCAL_ErrorMessage = "Heap Overflow";
FAIL;
}
#ifdef SFUNC
if (pe)
t = MkSFTerm(Yap_MkFunctor(a, SFArity), nargs, p, pe->NilValue);
else
t = Yap_MkApplTerm(Yap_MkFunctor(a, nargs), nargs, p);
#else
if (a == AtomDBref && nargs == 2)
t = MkDBRefTerm((DBRef)IntegerOfTerm(p[0]));
else
t = Yap_MkApplTerm(func, nargs, p);
#endif
if (HR > ASP-4096) {
LOCAL_ErrorMessage = "Stack Overflow";
return TermNil;
}
/* check for possible overflow against local stack */
checkfor(close, FailBuff PASS_REGS);
return t;
}
static Term MakeAccessor( Term t, Functor f USES_REGS )
{
UInt arity = ArityOfFunctor(FunctorOfTerm(t)), i;
Term tf[2], tl= TermNil;
tf[1] = ArgOfTerm(1, t);
for (i = arity; i > 1; i--) {
tl = MkPairTerm(ArgOfTerm(i, t), tl);
}
tf[0] = tl;
return Yap_MkApplTerm( f, 2, tf );
}
static Term
ParseList(read_data *rd, JMPBUFF *FailBuff USES_REGS)
{
Term o;
CELL *to_store;
o = AbsPair(HR);
loop:
to_store = HR;
HR+=2;
to_store[0] = ParseTerm(rd, 999, FailBuff PASS_REGS);
if (LOCAL_tokptr->Tok == Ord(Ponctuation_tok)) {
if (((int) LOCAL_tokptr->TokInfo) == ',') {
NextToken;
if (LOCAL_tokptr->Tok == Ord(Name_tok)
&& strcmp(RepAtom((Atom)(LOCAL_tokptr->TokInfo))->StrOfAE, "..") == 0) {
NextToken;
to_store[1] = ParseTerm(rd, 999, FailBuff PASS_REGS);
} else {
/* check for possible overflow against local stack */
if (HR > ASP-4096) {
to_store[1] = TermNil;
LOCAL_ErrorMessage = "Stack Overflow";
FAIL;
} else {
to_store[1] = AbsPair(HR);
goto loop;
}
}
} else if (((int) LOCAL_tokptr->TokInfo) == '|') {
NextToken;
to_store[1] = ParseTerm(rd, 999, FailBuff PASS_REGS);
} else {
to_store[1] = MkAtomTerm(AtomNil);
}
} else
FAIL;
return (o);
}
static Term
ParseTerm(read_data *rd, int prio, JMPBUFF *FailBuff USES_REGS)
{
/* parse term with priority prio */
Volatile Term t;
Volatile Functor func;
Volatile VarEntry *varinfo;
Volatile int curprio = 0, opprio, oplprio, oprprio;
Volatile Atom opinfo;
switch (LOCAL_tokptr->Tok) {
case Name_tok:
t = LOCAL_tokptr->TokInfo;
NextToken;
/* special rules apply for +1, -2.3, etc... */
if (LOCAL_tokptr->Tok == Number_tok) {
if ((Atom)t == AtomMinus) {
t = LOCAL_tokptr->TokInfo;
if (IsIntTerm(t))
t = MkIntTerm(-IntOfTerm(t));
else if (IsFloatTerm(t))
t = MkFloatTerm(-FloatOfTerm(t));
#ifdef USE_GMP
else if (IsBigIntTerm(t)) {
t = Yap_gmp_neg_big(t);
}
#endif
else
t = MkLongIntTerm(-LongIntOfTerm(t));
NextToken;
break;
}
}
if ((LOCAL_tokptr->Tok != Ord(Ponctuation_tok)
|| Unsigned(LOCAL_tokptr->TokInfo) != 'l')
&& IsPrefixOp((Atom)t, &opprio, &oprprio PASS_REGS)
) {
if (LOCAL_tokptr->Tok == Name_tok) {
Atom at = (Atom)LOCAL_tokptr->TokInfo;
#ifndef _MSC_VER
if ((Atom)t == AtomPlus) {
if (at == AtomInf) {
t = MkFloatTerm(INFINITY);
NextToken;
break;
} else if (at == AtomNan) {
t = MkFloatTerm(NAN);
NextToken;
break;
}
} else if ((Atom)t == AtomMinus) {
if (at == AtomInf) {
t = MkFloatTerm(-INFINITY);
NextToken;
break;
} else if (at == AtomNan) {
t = MkFloatTerm(NAN);
NextToken;
break;
}
}
#endif
}
if (opprio <= prio) {
/* try to parse as a prefix operator */
TRY(
/* build appl on the heap */
func = Yap_MkFunctor((Atom) t, 1);
if (func == NULL) {
LOCAL_ErrorMessage = "Heap Overflow";
FAIL;
}
t = ParseTerm(rd, oprprio, FailBuff PASS_REGS);
t = Yap_MkApplTerm(func, 1, &t);
/* check for possible overflow against local stack */
if (HR > ASP-4096) {
LOCAL_ErrorMessage = "Stack Overflow";
FAIL;
}
curprio = opprio;
,
break;
)
}
}
if (LOCAL_tokptr->Tok == Ord(Ponctuation_tok)
&& Unsigned(LOCAL_tokptr->TokInfo) == 'l')
t = ParseArgs(rd, (Atom) t, ')', FailBuff, 0L PASS_REGS);
else
t = MkAtomTerm((Atom)t);
break;
case Number_tok:
t = LOCAL_tokptr->TokInfo;
NextToken;
break;
case String_tok: /* build list on the heap */
{
Volatile char *p = (char *) LOCAL_tokptr->TokInfo;
t = Yap_CharsToTDQ(p, CurrentModule PASS_REGS);
if (!t) {
FAIL;
}
NextToken;
}
break;
case WString_tok: /* build list on the heap */
{
Volatile wchar_t *p = (wchar_t *) LOCAL_tokptr->TokInfo;
t = Yap_WCharsToTDQ(p, CurrentModule PASS_REGS);
if (!t) {
FAIL;
}
NextToken;
}
break;
case Var_tok:
varinfo = (VarEntry *) (LOCAL_tokptr->TokInfo);
if ((t = varinfo->VarAdr) == TermNil) {
t = varinfo->VarAdr = MkVarTerm();
}
NextToken;
break;
case Error_tok:
FAIL;
case Ponctuation_tok:
switch ((int) LOCAL_tokptr->TokInfo) {
case '(':
case 'l': /* non solo ( */
NextToken;
t = ParseTerm(rd, 1200, FailBuff PASS_REGS);
checkfor(')', FailBuff PASS_REGS);
break;
case '[':
NextToken;
if (LOCAL_tokptr->Tok == Ponctuation_tok &&
(int) LOCAL_tokptr->TokInfo == ']') {
t = TermNil;
NextToken;
break;
}
t = ParseList(rd, FailBuff PASS_REGS);
checkfor(']', FailBuff PASS_REGS);
break;
case '{':
NextToken;
if (LOCAL_tokptr->Tok == Ponctuation_tok &&
(int) LOCAL_tokptr->TokInfo == '}') {
t = MkAtomTerm(AtomBraces);
NextToken;
break;
}
t = ParseTerm(rd, 1200, FailBuff PASS_REGS);
t = Yap_MkApplTerm(FunctorBraces, 1, &t);
/* check for possible overflow against local stack */
if (HR > ASP-4096) {
LOCAL_ErrorMessage = "Stack Overflow";
FAIL;
}
checkfor('}', FailBuff PASS_REGS);
break;
default:
FAIL;
}
break;
case QuasiQuotes_tok:
{
qq_t *qq = (qq_t *)(LOCAL_tokptr->TokInfo);
term_t pv, positions = rd->subtpos, to;
Atom at;
Term tn;
CELL *tnp;
// from SWI, enter the list
/* prepare (if we are the first in term) */
if ( !rd->varnames )
rd->varnames = PL_new_term_ref();
if ( !rd->qq )
{ if ( rd->quasi_quotations )
{ rd->qq = rd->quasi_quotations;
} else
{ if ( !(rd->qq = PL_new_term_ref()) )
return FALSE;
}
// create positions term
if ( positions )
{ if ( !(pv = PL_new_term_refs(3)) ||
!PL_unify_term(positions,
PL_FUNCTOR, FUNCTOR_quasi_quotation_position5,
PL_INTPTR, qq->start.charno,
PL_VARIABLE,
PL_TERM, pv+0, // leave three open slots
PL_TERM, pv+1,
PL_TERM, pv+2) )
return FALSE;
} else
pv = 0;
/* push type */
if ( !(rd->qq_tail = PL_copy_term_ref(rd->qq)) )
return FALSE;
}
NextToken;
t = ParseTerm(rd, 1200, FailBuff PASS_REGS);
if (LOCAL_tokptr->Tok != QuasiQuotes_tok) {
FAIL;
}
if ( !( is_quasi_quotation_syntax(t, rd, &at)) )
FAIL;
/* Arg 2: the content */
tn = Yap_MkNewApplTerm( SWIFunctorToFunctor(FUNCTOR_quasi_quotation4), 4 );
tnp = RepAppl(tn)+1;
tnp[0] = MkAtomTerm(at);
if ( !get_quasi_quotation(Yap_InitSlot( ArgOfTerm(2, tn) PASS_REGS), &qq->text, qq->text+strlen((const char *)qq->text), rd) )
FAIL;
if ( positions )
{ intptr_t qqend = qq->end.charno;
// set_range_position(positions, -1, qqend PASS_LD);
if ( !PL_unify_term( Yap_InitSlot( ArgOfTerm(2, t) PASS_REGS),
PL_FUNCTOR, FUNCTOR_minus2,
PL_INTPTR, qq->mid.charno+2, /* end of | token */
PL_INTPTR, qqend-2) ) /* end minus "|}" */
FAIL;
}
tnp[2] = Yap_GetFromSlot(rd->varnames PASS_REGS); /* Arg 3: the var dictionary */
/* Arg 4: the result */
t = ArgOfTerm(4, tn);
if ( !(to = PL_new_term_ref()) ||
!PL_unify_list(rd->qq_tail, to, rd->qq_tail) ||
!PL_unify(to, Yap_InitSlot(tn PASS_REGS)) )
FAIL;
}
NextToken;
break;
default:
FAIL;
}
/* main loop to parse infix and posfix operators starts here */
while (TRUE) {
if (LOCAL_tokptr->Tok == Ord(Name_tok)
&& Yap_HasOp((Atom)(LOCAL_tokptr->TokInfo))) {
Atom save_opinfo = opinfo = (Atom)(LOCAL_tokptr->TokInfo);
if (IsInfixOp(save_opinfo, &opprio, &oplprio, &oprprio PASS_REGS)
&& opprio <= prio && oplprio >= curprio) {
/* try parsing as infix operator */
Volatile int oldprio = curprio;
TRY3(
func = Yap_MkFunctor((Atom) LOCAL_tokptr->TokInfo, 2);
if (func == NULL) {
LOCAL_ErrorMessage = "Heap Overflow";
FAIL;
}
NextToken;
{
Term args[2];
args[0] = t;
args[1] = ParseTerm(rd, oprprio, FailBuff PASS_REGS);
t = Yap_MkApplTerm(func, 2, args);
/* check for possible overflow against local stack */
if (HR > ASP-4096) {
LOCAL_ErrorMessage = "Stack Overflow";
FAIL;
}
},
curprio = opprio;
opinfo = save_opinfo;
continue;
,
opinfo = save_opinfo;
curprio = oldprio;
)
}
if (IsPosfixOp(opinfo, &opprio, &oplprio PASS_REGS)
&& opprio <= prio && oplprio >= curprio) {
/* parse as posfix operator */
Functor func = Yap_MkFunctor((Atom) LOCAL_tokptr->TokInfo, 1);
if (func == NULL) {
LOCAL_ErrorMessage = "Heap Overflow";
FAIL;
}
t = Yap_MkApplTerm(func, 1, &t);
/* check for possible overflow against local stack */
if (HR > ASP-4096) {
LOCAL_ErrorMessage = "Stack Overflow";
FAIL;
}
curprio = opprio;
NextToken;
continue;
}
break;
}
if (LOCAL_tokptr->Tok == Ord(Ponctuation_tok)) {
if (Unsigned(LOCAL_tokptr->TokInfo) == ',' &&
prio >= 1000 && curprio <= 999) {
Volatile Term args[2];
NextToken;
args[0] = t;
args[1] = ParseTerm(rd, 1000, FailBuff PASS_REGS);
t = Yap_MkApplTerm(FunctorComma, 2, args);
/* check for possible overflow against local stack */
if (HR > ASP-4096) {
LOCAL_ErrorMessage = "Stack Overflow";
FAIL;
}
curprio = 1000;
continue;
} else if (Unsigned(LOCAL_tokptr->TokInfo) == '|' &&
IsInfixOp(AtomVBar, &opprio, &oplprio, &oprprio PASS_REGS)
&& opprio <= prio && oplprio >= curprio) {
Volatile Term args[2];
NextToken;
args[0] = t;
args[1] = ParseTerm(rd, oprprio, FailBuff PASS_REGS);
t = Yap_MkApplTerm(FunctorVBar, 2, args);
/* check for possible overflow against local stack */
if (HR > ASP-4096) {
LOCAL_ErrorMessage = "Stack Overflow";
FAIL;
}
curprio = opprio;
continue;
} else if (Unsigned(LOCAL_tokptr->TokInfo) == '(' &&
IsPosfixOp(AtomEmptyBrackets, &opprio, &oplprio PASS_REGS)
&& opprio <= prio && oplprio >= curprio) {
t = ParseArgs(rd, AtomEmptyBrackets, ')', FailBuff, t PASS_REGS);
curprio = opprio;
continue;
} else if (Unsigned(LOCAL_tokptr->TokInfo) == '[' &&
IsPosfixOp(AtomEmptySquareBrackets, &opprio, &oplprio PASS_REGS)
&& opprio <= prio && oplprio >= curprio) {
t = ParseArgs(rd, AtomEmptySquareBrackets, ']', FailBuff, t PASS_REGS);
t = MakeAccessor(t, FunctorEmptySquareBrackets PASS_REGS);
curprio = opprio;
continue;
} else if (Unsigned(LOCAL_tokptr->TokInfo) == '{' &&
IsPosfixOp(AtomEmptyCurlyBrackets, &opprio, &oplprio PASS_REGS)
&& opprio <= prio && oplprio >= curprio) {
t = ParseArgs(rd, AtomEmptyCurlyBrackets, '}', FailBuff, t PASS_REGS);
t = MakeAccessor(t, FunctorEmptyCurlyBrackets PASS_REGS);
curprio = opprio;
continue;
}
}
if (LOCAL_tokptr->Tok <= Ord(WString_tok))
FAIL;
break;
}
#if DEBUG
if (GLOBAL_Option['p' - 'a' + 1]) {
Yap_DebugPutc(LOCAL_c_error_stream,'[');
Yap_DebugPlWrite(t);
Yap_DebugPutc(LOCAL_c_error_stream,']');
Yap_DebugPutc(LOCAL_c_error_stream,'\n');
}
#endif
return t;
}
Term
Yap_Parse(read_data *rd)
{
CACHE_REGS
Volatile Term t;
JMPBUFF FailBuff;
if (!sigsetjmp(FailBuff.JmpBuff, 0)) {
t = ParseTerm(rd, 1200, &FailBuff PASS_REGS);
if (LOCAL_tokptr->Tok != Ord(eot_tok))
return (0L);
return (t);
} else
return (0);
}
//! @}
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