123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143 |
- #include "parse/parse.h"
-
- #include <stdbool.h>
-
- #include "gen/gen.h"
-
- static int parse_expression(
- struct l2_lexer *lexer, struct l2_generator *gen, struct l2_parse_error *err);
-
- static int parse_function_impl(
- struct l2_lexer *lexer, struct l2_generator *gen, struct l2_parse_error *err) {
- l2_gen_stack_frame(gen);
- l2_lexer_consume(lexer); // {
-
- while (1) {
- struct l2_token *tok = l2_lexer_peek(lexer, 1);
- if (tok->kind == L2_TOK_EOF) {
- l2_parse_err(err, tok, "In function: Unexpected EOF");
- return -1;
- } else if (tok->kind == L2_TOK_CLOSE_BRACE) {
- l2_lexer_consume(lexer); // }
- break;
- }
-
- if (parse_expression(lexer, gen, err) < 0) {
- return -1;
- }
- }
-
- l2_gen_ret(gen);
- return 0;
- }
-
- static int parse_function(
- struct l2_lexer *lexer, struct l2_generator *gen, struct l2_parse_error *err) {
- l2_gen_flush(gen);
-
- struct l2_io_writer *prev_writer = gen->writer.w;
-
- // Generate the function to a buffer in memory
- struct l2_io_mem_writer w = {0};
- w.w.write = l2_io_mem_write;
- gen->writer.w = &w.w;
-
- // Generates three words; PUSH, 0, RJMP
- l2_gen_rjmp(gen, 0);
-
- l2_word pos = gen->pos;
-
- // Generate the function body itself
- int ret = parse_function_impl(lexer, gen, err);
- l2_gen_flush(gen);
- gen->writer.w = prev_writer;
- if (ret < 0) {
- free(w.mem);
- return -1;
- }
-
- l2_word *ops = (l2_word *)w.mem;
- l2_word opcount = w.len / sizeof(l2_word);
-
- // Due to the earlier gen_rjmp, the second word will be the argument to RJMP.
- // Need to set it properly to skip the function body.
- // The '- 3' is because we don't skip the PUSH, <count>, RJMP sequence.
- ops[1] = opcount - 3;
-
- l2_bufio_put_n(&gen->writer, ops, opcount * sizeof(l2_word));
- free(w.mem);
-
- l2_gen_function(gen, pos);
- return 0;
- }
-
- static int parse_expression(
- struct l2_lexer *lexer, struct l2_generator *gen, struct l2_parse_error *err) {
- struct l2_token *tok = l2_lexer_peek(lexer, 1);
- struct l2_token *tok2 = l2_lexer_peek(lexer, 2);
-
- if (tok->kind == L2_TOK_IDENT && tok2->kind == L2_TOK_COLON_EQ) {
- char *ident = l2_token_extract_str(tok);
- l2_lexer_consume(lexer); // ident
- l2_lexer_consume(lexer); // :=
-
- if (parse_expression(lexer, gen, err) < 0) {
- free(ident);
- return -1;
- }
-
- l2_gen_assignment(gen, &ident);
- return 0;
- } else if (tok->kind == L2_TOK_NUMBER) {
- l2_gen_number(gen, tok->v.num);
- l2_lexer_consume(lexer); // number
- return 0;
- } else if (tok->kind == L2_TOK_IDENT) {
- char *ident = l2_token_extract_str(tok);
- l2_lexer_consume(lexer); // ident
- l2_gen_namespace_lookup(gen, &ident);
- return 0;
- } else if (tok->kind == L2_TOK_STRING) {
- char *str = l2_token_extract_str(tok);
- l2_lexer_consume(lexer); // string
- l2_gen_string(gen, &str);
- return 0;
- } else if (tok->kind == L2_TOK_OPEN_BRACE) {
- return parse_function(lexer, gen, err);
- }
-
- l2_parse_err(err, tok, "In expression: Unexpected tokens %s, %s",
- l2_token_kind_name(tok->kind), l2_token_kind_name(tok2->kind));
- return -1;
- }
-
- int l2_parse_program(
- struct l2_lexer *lexer, struct l2_generator *gen, struct l2_parse_error *err) {
- l2_gen_stack_frame(gen);
-
- bool first = true;
-
- while (1) {
- struct l2_token *tok = l2_lexer_peek(lexer, 1);
- if (tok->kind == L2_TOK_EOF) {
- break;
- }
-
- // The previous expr left a value on the stack which we have to pop
- if (!first) {
- l2_gen_pop(gen);
- }
-
- if (parse_expression(lexer, gen, err) < 0) {
- l2_gen_halt(gen);
- l2_gen_flush(gen);
- return -1;
- }
-
- first = false;
- }
-
- l2_gen_halt(gen);
- l2_gen_flush(gen);
- return 0;
- }
|