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Move lr_parser implementation into a separate .c file

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This commit is contained in:
Max Brunsfeld 2014-06-04 13:34:37 -07:00
parent 63cde3967c
commit 9a4889176e
5 changed files with 371 additions and 246 deletions
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12
include/tree_sitter/parser/lexer.h
View file

@ -16,7 +16,7 @@ typedef struct {
int reached_end;
} ts_lexer;
static ts_lexer ts_lexer_make() {
static inline ts_lexer ts_lexer_make() {
ts_lexer result = {
.chunk = NULL,
.chunk_start = 0,
@ -29,15 +29,15 @@ static ts_lexer ts_lexer_make() {
return result;
}
static size_t ts_lexer_position(const ts_lexer *lexer) {
static inline size_t ts_lexer_position(const ts_lexer *lexer) {
return lexer->chunk_start + lexer->position_in_chunk;
}
static char ts_lexer_lookahead_char(const ts_lexer *lexer) {
static inline char ts_lexer_lookahead_char(const ts_lexer *lexer) {
return lexer->chunk[lexer->position_in_chunk];
}
static int ts_lexer_advance(ts_lexer *lexer) {
static inline int ts_lexer_advance(ts_lexer *lexer) {
static const char empty_chunk[1] = "";
if (lexer->position_in_chunk + 1 < lexer->chunk_size) {
lexer->position_in_chunk++;
@ -56,11 +56,11 @@ static int ts_lexer_advance(ts_lexer *lexer) {
return 1;
}
static void ts_lexer_start_token(ts_lexer *lexer) {
static inline void ts_lexer_start_token(ts_lexer *lexer) {
lexer->token_start_position = ts_lexer_position(lexer);
}
static ts_tree * ts_lexer_build_node(ts_lexer *lexer, ts_symbol symbol) {
static inline ts_tree * ts_lexer_build_node(ts_lexer *lexer, ts_symbol symbol) {
size_t current_position = ts_lexer_position(lexer);
size_t size = current_position - lexer->token_start_position;
size_t offset = lexer->token_start_position - lexer->token_end_position;

210
include/tree_sitter/parser/lr_parser.h
View file

@ -1,6 +1,10 @@
#ifndef TREE_SITTER_PARSER_LR_PARSER_H_
#define TREE_SITTER_PARSER_LR_PARSER_H_
#ifdef __cplusplus
extern "C" {
#endif
#include "tree_sitter/parser/stack.h"
#include "tree_sitter/parser/lexer.h"
@ -22,6 +26,15 @@ typedef struct {
} data;
} ts_parse_action;
#define SHIFT(to_state_value) \
{ .type = ts_parse_action_type_shift, .data = { .to_state = to_state_value } }
#define REDUCE(symbol_val, child_count_val) \
{ .type = ts_parse_action_type_reduce, .data = { .symbol = symbol_val, .child_count = child_count_val } }
#define ACCEPT_INPUT() \
{ .type = ts_parse_action_type_accept }
typedef struct {
ts_lexer lexer;
ts_stack stack;
@ -37,192 +50,17 @@ typedef struct {
} config;
} ts_lr_parser;
static ts_lr_parser *
ts_lr_parser_make(size_t symbol_count,
const ts_parse_action *parse_table,
const ts_state_id *lex_states,
ts_tree * (* lex_fn)(ts_lexer *, ts_state_id),
const int *hidden_symbol_flags,
const int *ubiquitous_symbol_flags) {
ts_lr_parser *result = malloc(sizeof(ts_lr_parser));
*result = (ts_lr_parser) {
.lexer = ts_lexer_make(),
.stack = ts_stack_make(),
.config = {
.symbol_count = symbol_count,
.parse_table = parse_table,
.lex_states = lex_states,
.lex_fn = lex_fn,
.hidden_symbol_flags = hidden_symbol_flags,
.ubiquitous_symbol_flags = ubiquitous_symbol_flags,
},
};
return result;
}
static const ts_parse_action *
ts_lr_parser_table_actions(ts_lr_parser *parser, ts_state_id state) {
return parser->config.parse_table + (state * parser->config.symbol_count);
}
static size_t
ts_lr_parser_breakdown_stack(ts_lr_parser *parser, ts_input_edit *edit) {
if (!edit) return 0;
ts_stack *stack = &parser->stack;
size_t position = 0;
for (;;) {
ts_tree *node = ts_stack_top_node(stack);
if (!node) break;
position = ts_stack_right_position(stack);
size_t child_count;
ts_tree **children = ts_tree_immediate_children(node, &child_count);
if (position <= edit->position && !children) break;
stack->size--;
position -= ts_tree_total_size(node);
for (size_t i = 0; i < child_count && position < edit->position; i++) {
ts_tree *child = children[i];
ts_state_id state = ts_stack_top_state(stack);
ts_state_id next_state = ts_lr_parser_table_actions(parser, state)[ts_tree_symbol(child)].data.to_state;
ts_stack_push(stack, next_state, child);
ts_tree_retain(child);
position += ts_tree_total_size(child);
}
ts_tree_release(node);
}
return position;
}
static void
ts_lr_parser_initialize(ts_lr_parser *parser, ts_input input, ts_input_edit *edit) {
if (!edit) ts_stack_shrink(&parser->stack, 0);
parser->lookahead = NULL;
parser->next_lookahead = NULL;
size_t position = ts_lr_parser_breakdown_stack(parser, edit);
input.seek_fn(input.data, position);
parser->lexer = ts_lexer_make();
parser->lexer.input = input;
ts_lexer_advance(&parser->lexer);
}
static void
ts_lr_parser_shift(ts_lr_parser *parser, ts_state_id parse_state) {
ts_stack_push(&parser->stack, parse_state, parser->lookahead);
parser->lookahead = parser->next_lookahead;
parser->next_lookahead = NULL;
}
static void
ts_lr_parser_reduce(ts_lr_parser *parser, ts_symbol symbol, size_t child_count) {
parser->next_lookahead = parser->lookahead;
parser->lookahead = ts_stack_reduce(&parser->stack,
symbol,
child_count,
parser->config.hidden_symbol_flags,
parser->config.ubiquitous_symbol_flags);
}
static ts_symbol *
ts_lr_parser_expected_symbols(ts_lr_parser *parser, size_t *count) {
*count = 0;
const ts_parse_action *actions = ts_lr_parser_table_actions(parser, ts_stack_top_state(&parser->stack));
for (size_t i = 0; i < parser->config.symbol_count; i++)
if (actions[i].type != ts_parse_action_type_error)
++(*count);
size_t n = 0;
ts_symbol *result = malloc(*count * sizeof(*result));
for (ts_symbol i = 0; i < parser->config.symbol_count; i++)
if (actions[i].type != ts_parse_action_type_error)
result[n++] = i;
return result;
}
static int
ts_lr_parser_handle_error(ts_lr_parser *parser) {
size_t count = 0;
ts_symbol *expected_symbols = ts_lr_parser_expected_symbols(parser, &count);
ts_tree *error = ts_tree_make_error(ts_lexer_lookahead_char(&parser->lexer), count, expected_symbols, 0, 0);
for (;;) {
ts_tree_release(parser->lookahead);
size_t position = ts_lexer_position(&parser->lexer);
parser->lookahead = parser->config.lex_fn(&parser->lexer, ts_lex_state_error);
int at_end = 0;
if (ts_lexer_position(&parser->lexer) == position)
at_end = !ts_lexer_advance(&parser->lexer);
if (at_end || ts_tree_symbol(parser->lookahead) == ts_builtin_sym_end) {
ts_stack_push(&parser->stack, 0, error);
return 0;
}
/*
* Unwind the stack, looking for a state in which this token
* may appear after an error.
*/
for (size_t j = 0; j < parser->stack.size; j++) {
size_t i = parser->stack.size - 1 - j;
ts_state_id stack_state = parser->stack.entries[i].state;
ts_parse_action action_on_error = ts_lr_parser_table_actions(parser, stack_state)[ts_builtin_sym_error];
if (action_on_error.type == ts_parse_action_type_shift) {
ts_state_id state_after_error = action_on_error.data.to_state;
if (ts_lr_parser_table_actions(parser, state_after_error)[ts_tree_symbol(parser->lookahead)].type != ts_parse_action_type_error) {
ts_stack_shrink(&parser->stack, i + 1);
ts_stack_push(&parser->stack, state_after_error, error);
return 1;
}
}
}
}
}
static ts_tree *
ts_lr_parser_tree_root(ts_lr_parser *parser) {
ts_stack *stack = &parser->stack;
ts_tree *top_node = ts_stack_top_node(stack);
if (stack->size <= 1)
return top_node;
if (ts_tree_symbol(top_node) == ts_builtin_sym_error)
return top_node;
size_t immediate_child_count;
ts_tree **immedate_children = ts_tree_immediate_children(top_node, &immediate_child_count);
stack->size--;
for (size_t i = 0; i < immediate_child_count; i++) {
ts_tree *child = immedate_children[i];
ts_tree_retain(child);
ts_state_id state = ts_stack_top_state(stack);
ts_state_id next_state = ts_lr_parser_table_actions(parser, state)[ts_tree_symbol(child)].data.to_state;
ts_stack_push(stack, next_state, child);
}
ts_tree *new_node = ts_stack_reduce(stack,
ts_tree_symbol(top_node),
stack->size,
parser->config.hidden_symbol_flags,
NULL);
ts_tree_release(top_node);
return new_node;
}
static ts_parse_action
ts_lr_parser_next_action(ts_lr_parser *parser) {
ts_state_id state = ts_stack_top_state(&parser->stack);
if (!parser->lookahead)
parser->lookahead = parser->config.lex_fn(&parser->lexer, parser->config.lex_states[state]);
return ts_lr_parser_table_actions(parser, state)[ts_tree_symbol(parser->lookahead)];
ts_lr_parser * ts_lr_parser_make(size_t symbol_count,
const ts_parse_action *parse_table,
const ts_state_id *lex_states,
ts_tree * (* lex_fn)(ts_lexer *, ts_state_id),
const int *hidden_symbol_flags,
const int *ubiquitous_symbol_flags);
void ts_lr_parser_initialize(ts_lr_parser *parser, ts_input input, ts_input_edit *edit);
ts_tree * ts_lr_parser_parse(ts_lr_parser *parser, const char **symbol_names);
#ifdef __cplusplus
}
#endif
#endif