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author | kartofen <mladenovnasko0@gmail.com> | 2025-06-21 23:52:33 +0300 |
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committer | kartofen <mladenovnasko0@gmail.com> | 2025-06-21 23:52:33 +0300 |
commit | 1cbaa39e3cc7e8948cbd5be5f2d18170fcdebfe0 (patch) | |
tree | e6dfb5bd8788664d48b04165e5aa2fc3b0590797 /lr0.c | |
parent | 333acd33d8fa58ca463677b704153a90fc8fad44 (diff) |
make lr0 and lexer modular
Diffstat (limited to 'lr0.c')
-rw-r--r-- | lr0.c | 304 |
1 files changed, 0 insertions, 304 deletions
@@ -1,304 +0,0 @@ -#include <stdio.h> -#include <stdlib.h> - -#define ARR_LEN(...) (sizeof(__VA_ARGS__) / sizeof(*(__VA_ARGS__))) - -enum symbol { - PLUS = 0, - MINUS, - LPAREN, - RPAREN, - N0, N1, - END_INPUT, - - EP, E, T, N, - SYMBOL_COUNT, -}; - -static inline int is_terminal(enum symbol s) { return s < E; } -static inline int is_nonterminal(enum symbol s) { return s >= E; } - -struct production { - enum symbol LHS; - enum symbol *RHS; - size_t nRHS; -}; - -#define PROD(LHS, _, ...) {LHS, (enum symbol[]){__VA_ARGS__}, sizeof((enum symbol[]){__VA_ARGS__})/sizeof(enum symbol)} - -static struct production grammar[] = { - PROD(EP, ->, E, END_INPUT), - PROD(E, -->, E, PLUS, T), - PROD(E, -->, E, MINUS, T), - PROD(E, -->, T), - PROD(T, -->, LPAREN, E, RPAREN), - PROD(T, -->, N), - PROD(N, -->, N0), - PROD(N, -->, N1), -}; - -void print_grammar() -{ - for(size_t i = 0; i < ARR_LEN(grammar); i++) { - printf("%d --> ", grammar[i].LHS); - for(size_t j = 0; j < grammar[i].nRHS; j++) - printf("%d ", grammar[i].RHS[j]); - printf("\n"); - } -} - -static int follow[SYMBOL_COUNT][SYMBOL_COUNT]; -void fill_follow_table(); -void print_follow_table() -{ - printf(" "); - for(size_t i = 0; i < SYMBOL_COUNT; i++) printf("%2zu ", i); - printf("\n"); - - for(size_t i = 0; i < SYMBOL_COUNT; i++) { - printf("%2zu ", i); - for(size_t j = 0; j < SYMBOL_COUNT; j++) - printf(" %s ", follow[i][j] ? "x" : " "); - printf("\n"); - } -} - -struct action { - enum action_type { - ACTION_NOT_SET = 0, ACTION_SHIFT, - ACTION_GOTO, ACTION_REDUCE, - ACTION_ACCEPT - } type; - size_t arg; -}; - -// THIS IS BAD, DONT DO IT LIKE THAT -#define TABLE_CAP 64 -static struct action table[TABLE_CAP][SYMBOL_COUNT]; -// DO IT LIKE THAT -// static struct action *(table[SYMBOL_COUNT]); -static size_t states; - -int table_insert(size_t state, enum symbol sym, struct action a); -void print_table() -{ - printf(" "); - for(size_t sym = 0; sym < SYMBOL_COUNT; sym++) printf("%2zu ", sym); - printf("\n"); - - char action_to_char[] = {[ACTION_SHIFT] = 's', [ACTION_REDUCE] = 'r', [ACTION_GOTO] = 'g'}; - for(size_t i = 0; i < states; i++) { - printf("%2zu ", i); - for(size_t sym = 0; sym < SYMBOL_COUNT; sym++) - if(table[i][sym].type == ACTION_ACCEPT) printf(" a "); - else if(table[i][sym].type) printf("%c%-2zu ", action_to_char[table[i][sym].type], table[i][sym].arg); - else printf(" "); - printf("\n"); - } -} - - -struct item { - size_t prod_idx; - size_t dot; -}; - -int items_eq(struct item *i1, struct item *i2) { return (i1->dot == i2->dot && i1->prod_idx == i2->prod_idx) ? 1 : 0; } -void print_set(struct item *set, size_t nset) -{ - printf("{"); - for(size_t i = 0; i < nset; i++) - printf("{%zu, %zu}, ", set[i].prod_idx, set[i].dot); - printf("}\n"); -} - -#define SEEN_SETS_CAP 64 -static struct { - struct item *items; - size_t nitems; - size_t state; -} seen_sets[SEEN_SETS_CAP]; -static size_t nseen_sets; - -void free_seen_sets() { for(size_t i = 0; i < nseen_sets; i++) free(seen_sets[i].items);} - -size_t handle_set(struct item *set, size_t nset); -int insert_set(size_t state, struct item *initial_set, size_t ninitial); -size_t closure(struct item *in_set, size_t nin, struct item *out_set, size_t nout); - -void *xcalloc(size_t n, size_t size) { void *addr = calloc(n, size); return addr ? addr : (exit(1), NULL); } - -int main(void) -{ - fill_follow_table(); - - handle_set((struct item[]){{0, 0}}, 1); - print_table(); - - free_seen_sets(); -} - -size_t handle_set(struct item *set, size_t nset) -{ - // 1. is set in seen_sets - for(size_t i = 0; i < nseen_sets; i++) { - if(seen_sets[i].nitems != nset) continue; - - int _seen = 0; - for(size_t j = 0; j < nset; j++) { - _seen = 0; - for(size_t k = 0; k < nset; k++) - if(items_eq(&seen_sets[i].items[k], &set[j])) _seen = 1; - if(!_seen) break; - } - if(_seen) return seen_sets[i].state; - } - - // 2. add set to seen_sets - if(nseen_sets >= SEEN_SETS_CAP) { - fprintf(stderr, "ERROR: SEEN_SET_CAP exceeded\n"); - exit(1); - } - - seen_sets[nseen_sets].items = xcalloc(nset, sizeof(*set)); - seen_sets[nseen_sets].nitems = nset; - for(size_t i = 0; i < nset; i++) - seen_sets[nseen_sets].items[i] = set[i]; - - // 3. insert new state - size_t new_state = seen_sets[nseen_sets++].state = states++; - if(new_state >= TABLE_CAP) { - fprintf(stderr, "ERROR: TABLE_CAP exceeded\n"); - exit(1); - } - - if(insert_set(new_state, set, nset)) { - fprintf(stderr, "ERROR: insert_set failed\n"); - exit(1); - } - - return new_state; -} - -#define CLOSURE_SET_CAP 64 -#define GOTO_SET_CAP 32 -int insert_set(size_t state, struct item *initial_set, size_t ninitial) -{ - struct item closure_set[CLOSURE_SET_CAP]; - - size_t nclosure = closure(initial_set, ninitial, closure_set, CLOSURE_SET_CAP); - if(nclosure > CLOSURE_SET_CAP) { - fprintf(stderr, "ERROR: CLOSURE_SET_CAP exceeded\n"); - return 1; - } - - for(size_t sym = 0; sym < SYMBOL_COUNT; sym++) { - struct item goto_set[GOTO_SET_CAP]; - size_t ngoto = 0; - - for(size_t j = 0; j < nclosure; j++) { - struct production *p = &grammar[closure_set[j].prod_idx]; - size_t dot = closure_set[j].dot; - - if(dot == p->nRHS) { - if(!follow[p->LHS][sym]) continue; - if(table_insert(state, sym, (struct action){ - ACTION_REDUCE, closure_set[j].prod_idx})) - return 1; - continue; - } - - if(p->RHS[dot] == sym) { - if(ngoto >= GOTO_SET_CAP) { - fprintf(stderr, "ERROR: GOTO_SET_CAP exceeded\n"); - return 1; - } - goto_set[ngoto] = closure_set[j]; - goto_set[ngoto++].dot++; - } - } - - if(ngoto == 0) continue; - - if(sym == END_INPUT) { - if(table_insert(state, sym, (struct action){ACTION_ACCEPT, 0})) - return 1; - continue; - } - - size_t new_state = handle_set(goto_set, ngoto); - - if(table_insert(state, sym, (struct action){ - is_terminal(sym) ? ACTION_SHIFT : ACTION_GOTO, - new_state})) return 1; - } - - return 0; -} - -size_t closure(struct item *in_set, size_t nin, struct item *out_set, size_t nout_max) -{ - size_t nout = nin; - - if(nout > nout_max) return nout; - for(size_t i = 0; i < nin; i++) out_set[i] = in_set[i]; - - int *is_in_closure = xcalloc(ARR_LEN(grammar), sizeof(int)); - for(size_t i = 0; i < nout; i++) - { - struct production *p = &grammar[out_set[i].prod_idx]; - if(out_set[i].dot == p->nRHS) continue; - enum symbol sym = p->RHS[out_set[i].dot]; - - for(size_t j = 0; j < ARR_LEN(grammar); j++) - if(grammar[j].LHS == sym) { - if(is_in_closure[j]) continue; - is_in_closure[j] = 1; - - if(nout++ >= nout_max) goto cleanup; - out_set[nout-1] = (struct item){j, 0}; - } - } - -cleanup: - free(is_in_closure); - return nout; -} - -void fill_follow_table() -{ - for(size_t i = 0; i < ARR_LEN(grammar); i++) { - struct production *p = &grammar[i]; - for(size_t j = 1; j < p->nRHS; j++) - follow[p->RHS[j-1]][p->RHS[j]] = 1; - } - -#define set(e) if((e) != 1) changed = (e) = 1 - - int changed; - do { - changed = 0; - for(size_t i = 0; i < ARR_LEN(grammar); i++) - for(size_t sym = 0; sym < SYMBOL_COUNT; sym++) { - struct production *p = &grammar[i]; - if(follow[p->LHS][sym]) - set(follow[p->RHS[p->nRHS-1]][sym]); - if(follow[sym][p->LHS]) - set(follow[sym][p->RHS[0]]); - } - } while(changed); -} - -int table_insert(size_t state, enum symbol sym, struct action a) -{ - if(table[state][sym].type != ACTION_NOT_SET) { - fprintf(stderr, "TABLE COLLISION on state '%zu' sym '%d'\n", state, sym); - fprintf(stderr, "\t{%d %zu} vs {%d %zu}", - table[state][sym].type, table[state][sym].arg, - a.type, a.arg); - return 1; - } - - table[state][sym] = a; - return 0; -} |