diff options
Diffstat (limited to 'AppPkg/Applications/Python/Python-2.7.2/Parser/parser.c')
| -rw-r--r-- | AppPkg/Applications/Python/Python-2.7.2/Parser/parser.c | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/AppPkg/Applications/Python/Python-2.7.2/Parser/parser.c b/AppPkg/Applications/Python/Python-2.7.2/Parser/parser.c new file mode 100644 index 0000000000..d98dfaaca5 --- /dev/null +++ b/AppPkg/Applications/Python/Python-2.7.2/Parser/parser.c @@ -0,0 +1,436 @@ +
+/* Parser implementation */
+
+/* For a description, see the comments at end of this file */
+
+/* XXX To do: error recovery */
+
+#include "Python.h"
+#include "pgenheaders.h"
+#include "token.h"
+#include "grammar.h"
+#include "node.h"
+#include "parser.h"
+#include "errcode.h"
+
+
+#ifdef Py_DEBUG
+extern int Py_DebugFlag;
+#define D(x) if (!Py_DebugFlag); else x
+#else
+#define D(x)
+#endif
+
+
+/* STACK DATA TYPE */
+
+static void s_reset(stack *);
+
+static void
+s_reset(stack *s)
+{
+ s->s_top = &s->s_base[MAXSTACK];
+}
+
+#define s_empty(s) ((s)->s_top == &(s)->s_base[MAXSTACK])
+
+static int
+s_push(register stack *s, dfa *d, node *parent)
+{
+ register stackentry *top;
+ if (s->s_top == s->s_base) {
+ fprintf(stderr, "s_push: parser stack overflow\n");
+ return E_NOMEM;
+ }
+ top = --s->s_top;
+ top->s_dfa = d;
+ top->s_parent = parent;
+ top->s_state = 0;
+ return 0;
+}
+
+#ifdef Py_DEBUG
+
+static void
+s_pop(register stack *s)
+{
+ if (s_empty(s))
+ Py_FatalError("s_pop: parser stack underflow -- FATAL");
+ s->s_top++;
+}
+
+#else /* !Py_DEBUG */
+
+#define s_pop(s) (s)->s_top++
+
+#endif
+
+
+/* PARSER CREATION */
+
+parser_state *
+PyParser_New(grammar *g, int start)
+{
+ parser_state *ps;
+
+ if (!g->g_accel)
+ PyGrammar_AddAccelerators(g);
+ ps = (parser_state *)PyMem_MALLOC(sizeof(parser_state));
+ if (ps == NULL)
+ return NULL;
+ ps->p_grammar = g;
+#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
+ ps->p_flags = 0;
+#endif
+ ps->p_tree = PyNode_New(start);
+ if (ps->p_tree == NULL) {
+ PyMem_FREE(ps);
+ return NULL;
+ }
+ s_reset(&ps->p_stack);
+ (void) s_push(&ps->p_stack, PyGrammar_FindDFA(g, start), ps->p_tree);
+ return ps;
+}
+
+void
+PyParser_Delete(parser_state *ps)
+{
+ /* NB If you want to save the parse tree,
+ you must set p_tree to NULL before calling delparser! */
+ PyNode_Free(ps->p_tree);
+ PyMem_FREE(ps);
+}
+
+
+/* PARSER STACK OPERATIONS */
+
+static int
+shift(register stack *s, int type, char *str, int newstate, int lineno, int col_offset)
+{
+ int err;
+ assert(!s_empty(s));
+ err = PyNode_AddChild(s->s_top->s_parent, type, str, lineno, col_offset);
+ if (err)
+ return err;
+ s->s_top->s_state = newstate;
+ return 0;
+}
+
+static int
+push(register stack *s, int type, dfa *d, int newstate, int lineno, int col_offset)
+{
+ int err;
+ register node *n;
+ n = s->s_top->s_parent;
+ assert(!s_empty(s));
+ err = PyNode_AddChild(n, type, (char *)NULL, lineno, col_offset);
+ if (err)
+ return err;
+ s->s_top->s_state = newstate;
+ return s_push(s, d, CHILD(n, NCH(n)-1));
+}
+
+
+/* PARSER PROPER */
+
+static int
+classify(parser_state *ps, int type, char *str)
+{
+ grammar *g = ps->p_grammar;
+ register int n = g->g_ll.ll_nlabels;
+
+ if (type == NAME) {
+ register char *s = str;
+ register label *l = g->g_ll.ll_label;
+ register int i;
+ for (i = n; i > 0; i--, l++) {
+ if (l->lb_type != NAME || l->lb_str == NULL ||
+ l->lb_str[0] != s[0] ||
+ strcmp(l->lb_str, s) != 0)
+ continue;
+#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
+ if (ps->p_flags & CO_FUTURE_PRINT_FUNCTION &&
+ s[0] == 'p' && strcmp(s, "print") == 0) {
+ break; /* no longer a keyword */
+ }
+#endif
+ D(printf("It's a keyword\n"));
+ return n - i;
+ }
+ }
+
+ {
+ register label *l = g->g_ll.ll_label;
+ register int i;
+ for (i = n; i > 0; i--, l++) {
+ if (l->lb_type == type && l->lb_str == NULL) {
+ D(printf("It's a token we know\n"));
+ return n - i;
+ }
+ }
+ }
+
+ D(printf("Illegal token\n"));
+ return -1;
+}
+
+#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
+static void
+future_hack(parser_state *ps)
+{
+ node *n = ps->p_stack.s_top->s_parent;
+ node *ch, *cch;
+ int i;
+
+ /* from __future__ import ..., must have at least 4 children */
+ n = CHILD(n, 0);
+ if (NCH(n) < 4)
+ return;
+ ch = CHILD(n, 0);
+ if (STR(ch) == NULL || strcmp(STR(ch), "from") != 0)
+ return;
+ ch = CHILD(n, 1);
+ if (NCH(ch) == 1 && STR(CHILD(ch, 0)) &&
+ strcmp(STR(CHILD(ch, 0)), "__future__") != 0)
+ return;
+ ch = CHILD(n, 3);
+ /* ch can be a star, a parenthesis or import_as_names */
+ if (TYPE(ch) == STAR)
+ return;
+ if (TYPE(ch) == LPAR)
+ ch = CHILD(n, 4);
+
+ for (i = 0; i < NCH(ch); i += 2) {
+ cch = CHILD(ch, i);
+ if (NCH(cch) >= 1 && TYPE(CHILD(cch, 0)) == NAME) {
+ char *str_ch = STR(CHILD(cch, 0));
+ if (strcmp(str_ch, FUTURE_WITH_STATEMENT) == 0) {
+ ps->p_flags |= CO_FUTURE_WITH_STATEMENT;
+ } else if (strcmp(str_ch, FUTURE_PRINT_FUNCTION) == 0) {
+ ps->p_flags |= CO_FUTURE_PRINT_FUNCTION;
+ } else if (strcmp(str_ch, FUTURE_UNICODE_LITERALS) == 0) {
+ ps->p_flags |= CO_FUTURE_UNICODE_LITERALS;
+ }
+ }
+ }
+}
+#endif /* future keyword */
+
+int
+PyParser_AddToken(register parser_state *ps, register int type, char *str,
+ int lineno, int col_offset, int *expected_ret)
+{
+ register int ilabel;
+ int err;
+
+ D(printf("Token %s/'%s' ... ", _PyParser_TokenNames[type], str));
+
+ /* Find out which label this token is */
+ ilabel = classify(ps, type, str);
+ if (ilabel < 0)
+ return E_SYNTAX;
+
+ /* Loop until the token is shifted or an error occurred */
+ for (;;) {
+ /* Fetch the current dfa and state */
+ register dfa *d = ps->p_stack.s_top->s_dfa;
+ register state *s = &d->d_state[ps->p_stack.s_top->s_state];
+
+ D(printf(" DFA '%s', state %d:",
+ d->d_name, ps->p_stack.s_top->s_state));
+
+ /* Check accelerator */
+ if (s->s_lower <= ilabel && ilabel < s->s_upper) {
+ register int x = s->s_accel[ilabel - s->s_lower];
+ if (x != -1) {
+ if (x & (1<<7)) {
+ /* Push non-terminal */
+ int nt = (x >> 8) + NT_OFFSET;
+ int arrow = x & ((1<<7)-1);
+ dfa *d1 = PyGrammar_FindDFA(
+ ps->p_grammar, nt);
+ if ((err = push(&ps->p_stack, nt, d1,
+ arrow, lineno, col_offset)) > 0) {
+ D(printf(" MemError: push\n"));
+ return err;
+ }
+ D(printf(" Push ...\n"));
+ continue;
+ }
+
+ /* Shift the token */
+ if ((err = shift(&ps->p_stack, type, str,
+ x, lineno, col_offset)) > 0) {
+ D(printf(" MemError: shift.\n"));
+ return err;
+ }
+ D(printf(" Shift.\n"));
+ /* Pop while we are in an accept-only state */
+ while (s = &d->d_state
+ [ps->p_stack.s_top->s_state],
+ s->s_accept && s->s_narcs == 1) {
+ D(printf(" DFA '%s', state %d: "
+ "Direct pop.\n",
+ d->d_name,
+ ps->p_stack.s_top->s_state));
+#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
+ if (d->d_name[0] == 'i' &&
+ strcmp(d->d_name,
+ "import_stmt") == 0)
+ future_hack(ps);
+#endif
+ s_pop(&ps->p_stack);
+ if (s_empty(&ps->p_stack)) {
+ D(printf(" ACCEPT.\n"));
+ return E_DONE;
+ }
+ d = ps->p_stack.s_top->s_dfa;
+ }
+ return E_OK;
+ }
+ }
+
+ if (s->s_accept) {
+#ifdef PY_PARSER_REQUIRES_FUTURE_KEYWORD
+ if (d->d_name[0] == 'i' &&
+ strcmp(d->d_name, "import_stmt") == 0)
+ future_hack(ps);
+#endif
+ /* Pop this dfa and try again */
+ s_pop(&ps->p_stack);
+ D(printf(" Pop ...\n"));
+ if (s_empty(&ps->p_stack)) {
+ D(printf(" Error: bottom of stack.\n"));
+ return E_SYNTAX;
+ }
+ continue;
+ }
+
+ /* Stuck, report syntax error */
+ D(printf(" Error.\n"));
+ if (expected_ret) {
+ if (s->s_lower == s->s_upper - 1) {
+ /* Only one possible expected token */
+ *expected_ret = ps->p_grammar->
+ g_ll.ll_label[s->s_lower].lb_type;
+ }
+ else
+ *expected_ret = -1;
+ }
+ return E_SYNTAX;
+ }
+}
+
+
+#ifdef Py_DEBUG
+
+/* DEBUG OUTPUT */
+
+void
+dumptree(grammar *g, node *n)
+{
+ int i;
+
+ if (n == NULL)
+ printf("NIL");
+ else {
+ label l;
+ l.lb_type = TYPE(n);
+ l.lb_str = STR(n);
+ printf("%s", PyGrammar_LabelRepr(&l));
+ if (ISNONTERMINAL(TYPE(n))) {
+ printf("(");
+ for (i = 0; i < NCH(n); i++) {
+ if (i > 0)
+ printf(",");
+ dumptree(g, CHILD(n, i));
+ }
+ printf(")");
+ }
+ }
+}
+
+void
+showtree(grammar *g, node *n)
+{
+ int i;
+
+ if (n == NULL)
+ return;
+ if (ISNONTERMINAL(TYPE(n))) {
+ for (i = 0; i < NCH(n); i++)
+ showtree(g, CHILD(n, i));
+ }
+ else if (ISTERMINAL(TYPE(n))) {
+ printf("%s", _PyParser_TokenNames[TYPE(n)]);
+ if (TYPE(n) == NUMBER || TYPE(n) == NAME)
+ printf("(%s)", STR(n));
+ printf(" ");
+ }
+ else
+ printf("? ");
+}
+
+void
+printtree(parser_state *ps)
+{
+ if (Py_DebugFlag) {
+ printf("Parse tree:\n");
+ dumptree(ps->p_grammar, ps->p_tree);
+ printf("\n");
+ printf("Tokens:\n");
+ showtree(ps->p_grammar, ps->p_tree);
+ printf("\n");
+ }
+ printf("Listing:\n");
+ PyNode_ListTree(ps->p_tree);
+ printf("\n");
+}
+
+#endif /* Py_DEBUG */
+
+/*
+
+Description
+-----------
+
+The parser's interface is different than usual: the function addtoken()
+must be called for each token in the input. This makes it possible to
+turn it into an incremental parsing system later. The parsing system
+constructs a parse tree as it goes.
+
+A parsing rule is represented as a Deterministic Finite-state Automaton
+(DFA). A node in a DFA represents a state of the parser; an arc represents
+a transition. Transitions are either labeled with terminal symbols or
+with non-terminals. When the parser decides to follow an arc labeled
+with a non-terminal, it is invoked recursively with the DFA representing
+the parsing rule for that as its initial state; when that DFA accepts,
+the parser that invoked it continues. The parse tree constructed by the
+recursively called parser is inserted as a child in the current parse tree.
+
+The DFA's can be constructed automatically from a more conventional
+language description. An extended LL(1) grammar (ELL(1)) is suitable.
+Certain restrictions make the parser's life easier: rules that can produce
+the empty string should be outlawed (there are other ways to put loops
+or optional parts in the language). To avoid the need to construct
+FIRST sets, we can require that all but the last alternative of a rule
+(really: arc going out of a DFA's state) must begin with a terminal
+symbol.
+
+As an example, consider this grammar:
+
+expr: term (OP term)*
+term: CONSTANT | '(' expr ')'
+
+The DFA corresponding to the rule for expr is:
+
+------->.---term-->.------->
+ ^ |
+ | |
+ \----OP----/
+
+The parse tree generated for the input a+b is:
+
+(expr: (term: (NAME: a)), (OP: +), (term: (NAME: b)))
+
+*/
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