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Revision 9b88e1587f7c0b9119c8ba2a11f9d4855f14aa0c authored by Raymond Hettinger on 29 April 2003, 04:37:13 UTC, committed by Raymond Hettinger on 29 April 2003, 04:37:13 UTC
A newbie found it difficult to translate the exampe into a case that used only short options or long options but not both. He tried to shorten the tuple search but forgot the trailing comma, The appropriate pattern is an equality check. Revised the example to point him in the right direction.
1 parent 971f0f0
Tip revision: 9b88e1587f7c0b9119c8ba2a11f9d4855f14aa0c authored by Raymond Hettinger on 29 April 2003, 04:37:13 UTC
SF bug #729096: getopt online documentation example improvement
SF bug #729096: getopt online documentation example improvement
Tip revision: 9b88e15
acceler.c
/* Parser accelerator module */
/* The parser as originally conceived had disappointing performance.
This module does some precomputation that speeds up the selection
of a DFA based upon a token, turning a search through an array
into a simple indexing operation. The parser now cannot work
without the accelerators installed. Note that the accelerators
are installed dynamically when the parser is initialized, they
are not part of the static data structure written on graminit.[ch]
by the parser generator. */
#include "pgenheaders.h"
#include "grammar.h"
#include "node.h"
#include "token.h"
#include "parser.h"
/* Forward references */
static void fixdfa(grammar *, dfa *);
static void fixstate(grammar *, state *);
void
PyGrammar_AddAccelerators(grammar *g)
{
dfa *d;
int i;
#ifdef Py_DEBUG
fprintf(stderr, "Adding parser accelerators ...\n");
#endif
d = g->g_dfa;
for (i = g->g_ndfas; --i >= 0; d++)
fixdfa(g, d);
g->g_accel = 1;
#ifdef Py_DEBUG
fprintf(stderr, "Done.\n");
#endif
}
void
PyGrammar_RemoveAccelerators(grammar *g)
{
dfa *d;
int i;
g->g_accel = 0;
d = g->g_dfa;
for (i = g->g_ndfas; --i >= 0; d++) {
state *s;
int j;
s = d->d_state;
for (j = 0; j < d->d_nstates; j++, s++) {
if (s->s_accel)
PyMem_DEL(s->s_accel);
s->s_accel = NULL;
}
}
}
static void
fixdfa(grammar *g, dfa *d)
{
state *s;
int j;
s = d->d_state;
for (j = 0; j < d->d_nstates; j++, s++)
fixstate(g, s);
}
static void
fixstate(grammar *g, state *s)
{
arc *a;
int k;
int *accel;
int nl = g->g_ll.ll_nlabels;
s->s_accept = 0;
accel = PyMem_NEW(int, nl);
for (k = 0; k < nl; k++)
accel[k] = -1;
a = s->s_arc;
for (k = s->s_narcs; --k >= 0; a++) {
int lbl = a->a_lbl;
label *l = &g->g_ll.ll_label[lbl];
int type = l->lb_type;
if (a->a_arrow >= (1 << 7)) {
printf("XXX too many states!\n");
continue;
}
if (ISNONTERMINAL(type)) {
dfa *d1 = PyGrammar_FindDFA(g, type);
int ibit;
if (type - NT_OFFSET >= (1 << 7)) {
printf("XXX too high nonterminal number!\n");
continue;
}
for (ibit = 0; ibit < g->g_ll.ll_nlabels; ibit++) {
if (testbit(d1->d_first, ibit)) {
#ifdef applec
#define MPW_881_BUG /* Undefine if bug below is fixed */
#endif
#ifdef MPW_881_BUG
/* In 881 mode MPW 3.1 has a code
generation bug which seems to
set the upper bits; fix this by
explicitly masking them off */
int temp;
#endif
if (accel[ibit] != -1)
printf("XXX ambiguity!\n");
#ifdef MPW_881_BUG
temp = 0xFFFF &
(a->a_arrow | (1 << 7) |
((type - NT_OFFSET) << 8));
accel[ibit] = temp;
#else
accel[ibit] = a->a_arrow | (1 << 7) |
((type - NT_OFFSET) << 8);
#endif
}
}
}
else if (lbl == EMPTY)
s->s_accept = 1;
else if (lbl >= 0 && lbl < nl)
accel[lbl] = a->a_arrow;
}
while (nl > 0 && accel[nl-1] == -1)
nl--;
for (k = 0; k < nl && accel[k] == -1;)
k++;
if (k < nl) {
int i;
s->s_accel = PyMem_NEW(int, nl-k);
if (s->s_accel == NULL) {
fprintf(stderr, "no mem to add parser accelerators\n");
exit(1);
}
s->s_lower = k;
s->s_upper = nl;
for (i = 0; k < nl; i++, k++)
s->s_accel[i] = accel[k];
}
PyMem_DEL(accel);
}
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