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micropython/py/parse.c

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#include <unistd.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>
#include "misc.h"
#include "mpyconfig.h"
#include "lexer.h"
#include "parse.h"
#define RULE_ACT_KIND_MASK (0xf0)
#define RULE_ACT_ARG_MASK (0x0f)
#define RULE_ACT_OR (0x10)
#define RULE_ACT_AND (0x20)
#define RULE_ACT_LIST (0x30)
#define RULE_ARG_BLANK (0x0000)
#define RULE_ARG_KIND_MASK (0xf000)
#define RULE_ARG_ARG_MASK (0x0fff)
#define RULE_ARG_TOK (0x1000)
#define RULE_ARG_RULE (0x2000)
#define RULE_ARG_OPT_TOK (0x3000)
#define RULE_ARG_OPT_RULE (0x4000)
// (un)comment to use rule names; for debugging
//#define USE_RULE_NAME (1)
typedef struct _rule_t {
byte rule_id;
byte act;
#ifdef USE_RULE_NAME
const char *rule_name;
#endif
uint16_t arg[];
} rule_t;
enum {
RULE_none = 0,
#define DEF_RULE(rule, comp, kind, arg...) RULE_##rule,
#include "grammar.h"
#undef DEF_RULE
RULE_maximum_number_of,
};
#define or(n) (RULE_ACT_OR | n)
#define and(n) (RULE_ACT_AND | n)
#define one_or_more (RULE_ACT_LIST | 2)
#define list (RULE_ACT_LIST | 1)
#define list_with_end (RULE_ACT_LIST | 3)
#define tok(t) (RULE_ARG_TOK | PY_TOKEN_##t)
#define rule(r) (RULE_ARG_RULE | RULE_##r)
#define opt_tok(t) (RULE_ARG_OPT_TOK | PY_TOKEN_##t)
#define opt_rule(r) (RULE_ARG_OPT_RULE | RULE_##r)
#ifdef USE_RULE_NAME
#define DEF_RULE(rule, comp, kind, arg...) static rule_t rule_##rule = { RULE_##rule, kind, #rule, { arg } };
#else
#define DEF_RULE(rule, comp, kind, arg...) static rule_t rule_##rule = { RULE_##rule, kind, { arg } };
#endif
#include "grammar.h"
#undef or
#undef and
#undef list
#undef list_with_end
#undef tok
#undef rule
#undef opt_tok
#undef opt_rule
#undef one_or_more
#undef DEF_RULE
static rule_t *rules[] = {
NULL,
#define DEF_RULE(rule, comp, kind, arg...) &rule_##rule,
#include "grammar.h"
#undef DEF_RULE
};
typedef struct _rule_stack_t {
byte rule_id;
int32_t arg_i; // what should be the size and signedness?
} rule_stack_t;
typedef struct _parser_t {
uint rule_stack_alloc;
uint rule_stack_top;
rule_stack_t *rule_stack;
uint result_stack_top;
py_parse_node_t *result_stack;
} parser_t;
static void push_rule(parser_t *parser, rule_t *rule, int arg_i) {
if (parser->rule_stack_top >= parser->rule_stack_alloc) {
parser->rule_stack_alloc *= 2;
parser->rule_stack = m_renew(rule_stack_t, parser->rule_stack, parser->rule_stack_alloc);
}
parser->rule_stack[parser->rule_stack_top].rule_id = rule->rule_id;
parser->rule_stack[parser->rule_stack_top].arg_i = arg_i;
parser->rule_stack_top += 1;
}
static void push_rule_from_arg(parser_t *parser, uint arg) {
assert((arg & RULE_ARG_KIND_MASK) == RULE_ARG_RULE || (arg & RULE_ARG_KIND_MASK) == RULE_ARG_OPT_RULE);
uint rule_id = arg & RULE_ARG_ARG_MASK;
assert(rule_id < RULE_maximum_number_of);
push_rule(parser, rules[rule_id], 0);
}
static void pop_rule(parser_t *parser, rule_t **rule, uint *arg_i) {
parser->rule_stack_top -= 1;
*rule = rules[parser->rule_stack[parser->rule_stack_top].rule_id];
*arg_i = parser->rule_stack[parser->rule_stack_top].arg_i;
}
py_parse_node_t py_parse_node_new_leaf(machine_int_t kind, machine_int_t arg) {
return (py_parse_node_t)(kind | (arg << 4));
}
int num_parse_nodes_allocated = 0;
py_parse_node_struct_t *parse_node_new_struct(int rule_id, int num_args) {
py_parse_node_struct_t *pn = m_malloc(sizeof(py_parse_node_struct_t) + num_args * sizeof(py_parse_node_t));
pn->source = 0; // TODO
pn->kind_num_nodes = (rule_id & 0xff) | (num_args << 8);
num_parse_nodes_allocated += 1;
return pn;
}
void parse_node_show(py_parse_node_t pn, int indent) {
for (int i = 0; i < indent; i++) {
printf(" ");
}
if (PY_PARSE_NODE_IS_NULL(pn)) {
printf("NULL\n");
} else if (PY_PARSE_NODE_IS_LEAF(pn)) {
int arg = PY_PARSE_NODE_LEAF_ARG(pn);
switch (PY_PARSE_NODE_LEAF_KIND(pn)) {
case PY_PARSE_NODE_ID: printf("id(%s)\n", qstr_str(arg)); break;
case PY_PARSE_NODE_SMALL_INT: printf("int(%d)\n", arg); break;
case PY_PARSE_NODE_INTEGER: printf("int(%s)\n", qstr_str(arg)); break;
case PY_PARSE_NODE_DECIMAL: printf("dec(%s)\n", qstr_str(arg)); break;
case PY_PARSE_NODE_STRING: printf("str(%s)\n", qstr_str(arg)); break;
case PY_PARSE_NODE_BYTES: printf("bytes(%s)\n", qstr_str(arg)); break;
case PY_PARSE_NODE_TOKEN: printf("tok(%d)\n", arg); break;
default: assert(0);
}
} else {
py_parse_node_struct_t *pns2 = (py_parse_node_struct_t*)pn;
int n = pns2->kind_num_nodes >> 8;
#ifdef USE_RULE_NAME
printf("%s(%d) (n=%d)\n", rules[PY_PARSE_NODE_STRUCT_KIND(pns2)]->rule_name, PY_PARSE_NODE_STRUCT_KIND(pns2), n);
#else
printf("rule(%u) (n=%d)\n", (uint)PY_PARSE_NODE_STRUCT_KIND(pns2), n);
#endif
for (int i = 0; i < n; i++) {
parse_node_show(pns2->nodes[i], indent + 2);
}
}
}
/*
static void result_stack_show(parser_t *parser) {
printf("result stack, most recent first\n");
for (int i = parser->result_stack_top - 1; i >= 0; i--) {
parse_node_show(parser->result_stack[i], 0);
}
}
*/
static py_parse_node_t pop_result(parser_t *parser) {
assert(parser->result_stack_top > 0);
return parser->result_stack[--parser->result_stack_top];
}
static py_parse_node_t peek_result(parser_t *parser, int pos) {
assert(parser->result_stack_top > pos);
return parser->result_stack[parser->result_stack_top - 1 - pos];
}
static void push_result_node(parser_t *parser, py_parse_node_t pn) {
parser->result_stack[parser->result_stack_top++] = pn;
}
static void push_result_token(parser_t *parser, const py_lexer_t *lex) {
const py_token_t *tok = py_lexer_cur(lex);
py_parse_node_t pn;
if (tok->kind == PY_TOKEN_NAME) {
pn = py_parse_node_new_leaf(PY_PARSE_NODE_ID, qstr_from_strn_copy(tok->str, tok->len));
} else if (tok->kind == PY_TOKEN_NUMBER) {
bool dec = false;
bool small_int = true;
int int_val = 0;
int len = tok->len;
const char *str = tok->str;
int base = 10;
int i = 0;
if (len >= 3 && str[0] == '0') {
if (str[1] == 'o' || str[1] == 'O') {
// octal
base = 8;
i = 2;
} else if (str[1] == 'x' || str[1] == 'X') {
// hexadecimal
base = 16;
i = 2;
} else if (str[1] == 'b' || str[1] == 'B') {
// binary
base = 2;
i = 2;
}
}
for (; i < len; i++) {
if (g_unichar_isdigit(str[i]) && str[i] - '0' < base) {
int_val = base * int_val + str[i] - '0';
} else if (base == 16 && 'a' <= str[i] && str[i] <= 'f') {
int_val = base * int_val + str[i] - 'a' + 10;
} else if (base == 16 && 'F' <= str[i] && str[i] <= 'F') {
int_val = base * int_val + str[i] - 'A' + 10;
} else if (str[i] == '.' || str[i] == 'e' || str[i] == 'E') {
dec = true;
break;
} else {
small_int = false;
break;
}
}
if (dec) {
pn = py_parse_node_new_leaf(PY_PARSE_NODE_DECIMAL, qstr_from_strn_copy(str, len));
} else if (small_int && -0x800000 <= int_val && int_val <= 0x7fffff) { // XXX check this range formula!
pn = py_parse_node_new_leaf(PY_PARSE_NODE_SMALL_INT, int_val);
} else {
pn = py_parse_node_new_leaf(PY_PARSE_NODE_INTEGER, qstr_from_strn_copy(str, len));
}
} else if (tok->kind == PY_TOKEN_STRING) {
pn = py_parse_node_new_leaf(PY_PARSE_NODE_STRING, qstr_from_strn_copy(tok->str, tok->len));
} else if (tok->kind == PY_TOKEN_BYTES) {
pn = py_parse_node_new_leaf(PY_PARSE_NODE_BYTES, qstr_from_strn_copy(tok->str, tok->len));
} else {
pn = py_parse_node_new_leaf(PY_PARSE_NODE_TOKEN, tok->kind);
}
push_result_node(parser, pn);
}
static void push_result_rule(parser_t *parser, rule_t *rule, int num_args) {
py_parse_node_struct_t *pn = parse_node_new_struct(rule->rule_id, num_args);
for (int i = num_args; i > 0; i--) {
pn->nodes[i - 1] = pop_result(parser);
}
push_result_node(parser, (py_parse_node_t)pn);
}
py_parse_node_t py_parse(py_lexer_t *lex, int wanted_rule) {
wanted_rule = RULE_file_input;
parser_t *parser = m_new(parser_t, 1);
parser->rule_stack_alloc = 64;
parser->rule_stack_top = 0;
parser->rule_stack = m_new(rule_stack_t, parser->rule_stack_alloc);
parser->result_stack = m_new(py_parse_node_t, 1000);
parser->result_stack_top = 0;
push_rule(parser, rules[wanted_rule], 0);
uint n, i;
bool backtrack = false;
rule_t *rule;
py_token_kind_t tok_kind;
bool emit_rule;
bool had_trailing_sep;
for (;;) {
next_rule:
if (parser->rule_stack_top == 0) {
break;
}
pop_rule(parser, &rule, &i);
n = rule->act & RULE_ACT_ARG_MASK;
/*
// debugging
printf("depth=%d ", parser->rule_stack_top);
for (int j = 0; j < parser->rule_stack_top; ++j) {
printf(" ");
}
printf("%s n=%d i=%d bt=%d\n", rule->rule_name, n, i, backtrack);
*/
switch (rule->act & RULE_ACT_KIND_MASK) {
case RULE_ACT_OR:
if (i > 0 && !backtrack) {
goto next_rule;
} else {
backtrack = false;
}
for (; i < n - 1; ++i) {
switch (rule->arg[i] & RULE_ARG_KIND_MASK) {
case RULE_ARG_TOK:
if (py_lexer_is_kind(lex, rule->arg[i] & RULE_ARG_ARG_MASK)) {
push_result_token(parser, lex);
py_lexer_to_next(lex);
goto next_rule;
}
break;
case RULE_ARG_RULE:
push_rule(parser, rule, i + 1);
push_rule_from_arg(parser, rule->arg[i]);
goto next_rule;
default:
assert(0);
}
}
if ((rule->arg[i] & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
if (py_lexer_is_kind(lex, rule->arg[i] & RULE_ARG_ARG_MASK)) {
push_result_token(parser, lex);
py_lexer_to_next(lex);
} else {
backtrack = true;
goto next_rule;
}
} else {
push_rule_from_arg(parser, rule->arg[i]);
}
break;
case RULE_ACT_AND:
// failed, backtrack if we can, else syntax error
if (backtrack) {
assert(i > 0);
if ((rule->arg[i - 1] & RULE_ARG_KIND_MASK) == RULE_ARG_OPT_RULE) {
// an optional rule that failed, so continue with next arg
push_result_node(parser, PY_PARSE_NODE_NULL);
backtrack = false;
} else {
// a mandatory rule that failed, so propagate backtrack
if (i > 1) {
// already eaten tokens so can't backtrack
goto syntax_error;
} else {
goto next_rule;
}
}
}
// progress through the rule
for (; i < n; ++i) {
switch (rule->arg[i] & RULE_ARG_KIND_MASK) {
case RULE_ARG_TOK:
// need to match a token
tok_kind = rule->arg[i] & RULE_ARG_ARG_MASK;
if (py_lexer_is_kind(lex, tok_kind)) {
// matched token
if (tok_kind == PY_TOKEN_NAME) {
push_result_token(parser, lex);
}
py_lexer_to_next(lex);
} else {
// failed to match token
if (i > 0) {
// already eaten tokens so can't backtrack
goto syntax_error;
} else {
// this rule failed, so backtrack
backtrack = true;
goto next_rule;
}
}
break;
case RULE_ARG_RULE:
//if (i + 1 < n) {
push_rule(parser, rule, i + 1);
//}
push_rule_from_arg(parser, rule->arg[i]);
goto next_rule;
case RULE_ARG_OPT_RULE:
push_rule(parser, rule, i + 1);
push_rule_from_arg(parser, rule->arg[i]);
goto next_rule;
default:
assert(0);
}
}
assert(i == n);
// matched the rule, so now build the corresponding parse_node
// count number of arguments for the parse_node
i = 0;
emit_rule = false;
for (int x = 0; x < n; ++x) {
if ((rule->arg[x] & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
tok_kind = rule->arg[x] & RULE_ARG_ARG_MASK;
if (tok_kind >= PY_TOKEN_NAME) {
emit_rule = true;
}
if (tok_kind == PY_TOKEN_NAME) {
// only tokens which were names are pushed to stack
i += 1;
}
} else {
// rules are always pushed
i += 1;
}
}
// always emit these rules, even if they have only 1 argument
if (rule->rule_id == RULE_expr_stmt || rule->rule_id == RULE_yield_stmt) {
emit_rule = true;
}
// never emit these rules if they have only 1 argument
// NOTE: can't put atom_paren here because we need it to distinguisg, for example, [a,b] from [(a,b)]
// TODO possibly put varargslist_name, varargslist_equal here as well
if (rule->rule_id == RULE_else_stmt || rule->rule_id == RULE_testlist_comp_3b || rule->rule_id == RULE_import_as_names_paren || rule->rule_id == RULE_typedargslist_name || rule->rule_id == RULE_typedargslist_colon || rule->rule_id == RULE_typedargslist_equal || rule->rule_id == RULE_dictorsetmaker_colon || rule->rule_id == RULE_classdef_2 || rule->rule_id == RULE_with_item_as || rule->rule_id == RULE_assert_stmt_extra || rule->rule_id == RULE_as_name || rule->rule_id == RULE_raise_stmt_from || rule->rule_id == RULE_vfpdef) {
emit_rule = false;
}
// always emit these rules, and add an extra blank node at the end (to be used by the compiler to store data)
if (rule->rule_id == RULE_funcdef || rule->rule_id == RULE_classdef || rule->rule_id == RULE_comp_for || rule->rule_id == RULE_lambdef || rule->rule_id == RULE_lambdef_nocond) {
emit_rule = true;
push_result_node(parser, PY_PARSE_NODE_NULL);
i += 1;
}
int num_not_nil = 0;
for (int x = 0; x < i; ++x) {
if (peek_result(parser, x) != PY_PARSE_NODE_NULL) {
num_not_nil += 1;
}
}
//printf("done and %s n=%d i=%d notnil=%d\n", rule->rule_name, n, i, num_not_nil);
if (emit_rule) {
push_result_rule(parser, rule, i);
} else if (num_not_nil == 0) {
push_result_rule(parser, rule, i); // needed for, eg, atom_paren, testlist_comp_3b
//result_stack_show(parser);
//assert(0);
} else if (num_not_nil == 1) {
// single result, leave it on stack
py_parse_node_t pn = PY_PARSE_NODE_NULL;
for (int x = 0; x < i; ++x) {
py_parse_node_t pn2 = pop_result(parser);
if (pn2 != PY_PARSE_NODE_NULL) {
pn = pn2;
}
}
push_result_node(parser, pn);
} else {
push_result_rule(parser, rule, i);
}
break;
case RULE_ACT_LIST:
// n=2 is: item item*
// n=1 is: item (sep item)*
// n=3 is: item (sep item)* [sep]
if (backtrack) {
list_backtrack:
had_trailing_sep = false;
if (n == 2) {
if (i == 1) {
// fail on item, first time round; propagate backtrack
goto next_rule;
} else {
// fail on item, in later rounds; finish with this rule
backtrack = false;
}
} else {
if (i == 1) {
// fail on item, first time round; propagate backtrack
goto next_rule;
} else if ((i & 1) == 1) {
// fail on item, in later rounds; have eaten tokens so can't backtrack
if (n == 3) {
// list allows trailing separator; finish parsing list
had_trailing_sep = true;
backtrack = false;
} else {
// list doesn't allowing trailing separator; fail
goto syntax_error;
}
} else {
// fail on separator; finish parsing list
backtrack = false;
}
}
} else {
for (;;) {
uint arg = rule->arg[i & 1 & n];
switch (arg & RULE_ARG_KIND_MASK) {
case RULE_ARG_TOK:
if (py_lexer_is_kind(lex, arg & RULE_ARG_ARG_MASK)) {
if (i & 1 & n) {
// separators which are tokens are not pushed to result stack
} else {
push_result_token(parser, lex);
}
py_lexer_to_next(lex);
// got element of list, so continue parsing list
i += 1;
} else {
// couldn't get element of list
i += 1;
backtrack = true;
goto list_backtrack;
}
break;
case RULE_ARG_RULE:
push_rule(parser, rule, i + 1);
push_rule_from_arg(parser, arg);
goto next_rule;
default:
assert(0);
}
}
}
assert(i >= 1);
// compute number of elements in list, result in i
i -= 1;
if ((n & 1) && (rule->arg[1] & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
// don't count separators when they are tokens
i = (i + 1) / 2;
}
if (i == 1) {
// list matched single item
if (had_trailing_sep) {
// if there was a trailing separator, make a list of a single item
push_result_rule(parser, rule, i);
} else {
// just leave single item on stack (ie don't wrap in a list)
}
} else {
//printf("done list %s %d %d\n", rule->rule_name, n, i);
push_result_rule(parser, rule, i);
}
break;
default:
assert(0);
}
}
// check we are at the end of the token stream
if (!py_lexer_is_kind(lex, PY_TOKEN_END)) {
goto syntax_error;
}
//printf("--------------\n");
//result_stack_show(parser);
assert(parser->result_stack_top == 1);
//printf("maximum depth: %d\n", parser->rule_stack_alloc);
//printf("number of parse nodes allocated: %d\n", num_parse_nodes_allocated);
return parser->result_stack[0];
syntax_error:
if (py_lexer_is_kind(lex, PY_TOKEN_INDENT)) {
py_lexer_show_error_pythonic(lex, "IndentationError: unexpected indent");
} else if (py_lexer_is_kind(lex, PY_TOKEN_DEDENT_MISMATCH)) {
py_lexer_show_error_pythonic(lex, "IndentationError: unindent does not match any outer indentation level");
} else {
py_lexer_show_error_pythonic(lex, "syntax error:");
#ifdef USE_RULE_NAME
py_lexer_show_error(lex, rule->rule_name);
#endif
py_token_show(py_lexer_cur(lex));
}
return PY_PARSE_NODE_NULL;
}
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