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- #include "parse/parse.h"
-
- #include "gen/gen.h"
-
- static int is_end_tok(struct l2_token *tok) {
- return
- tok->kind == L2_TOK_CLOSE_PAREN || tok->kind == L2_TOK_CLOSE_BRACE ||
- tok->kind == L2_TOK_CLOSE_BRACKET || tok->kind == L2_TOK_EOL ||
- tok->kind == L2_TOK_EOF;
- }
-
- 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_lexer_consume(lexer); // {
- l2_lexer_skip_opt(lexer, L2_TOK_EOL);
-
- int first = 1;
- 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;
- }
-
- // 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) {
- return -1;
- }
-
- l2_lexer_skip_opt(lexer, L2_TOK_EOL);
- first = 0;
- }
-
- 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_sub_expression(
- struct l2_lexer *lexer, struct l2_generator *gen, struct l2_parse_error *err) {
- struct l2_token *tok = l2_lexer_peek(lexer, 1);
-
- if (tok->kind == L2_TOK_OPEN_PAREN) {
- l2_lexer_consume(lexer); // (
- tok = l2_lexer_peek(lexer, 1);
-
- // Special case: (foo) should be interpreted as a function call
- if (
- tok->kind == L2_TOK_IDENT &&
- l2_lexer_peek(lexer, 2)->kind == L2_TOK_CLOSE_PAREN) {
- char *ident = l2_token_extract_str(tok);
- l2_lexer_consume(lexer); // ident
- l2_lexer_consume(lexer); // )
-
- l2_gen_push(gen, 0); // Arg count
- l2_gen_namespace_lookup(gen, &ident);
- l2_gen_func_call(gen);
- return 0;
- }
-
- if (parse_expression(lexer, gen, err) < 0) {
- return -1;
- }
-
- if (tok->kind != L2_TOK_CLOSE_PAREN) {
- l2_parse_err(err, tok, "In paren expression: Expected close paren, got %s",
- l2_token_kind_name(tok->kind));
- return -1;
- }
-
- l2_lexer_consume(lexer); // )
- 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 token %s",
- l2_token_kind_name(tok->kind));
- return -1;
- }
-
- 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_IDENT && !is_end_tok(tok2)) {
- char *ident = l2_token_extract_str(tok);
- l2_lexer_consume(lexer);
-
- l2_word count = 0;
- while (!is_end_tok(l2_lexer_peek(lexer, 1))) {
- count += 1;
- if (parse_sub_expression(lexer, gen, err) < 0) {
- return -1;
- }
- }
-
- l2_gen_push(gen, count);
- l2_gen_namespace_lookup(gen, &ident);
- l2_gen_func_call(gen);
- return 0;
- }
-
- return parse_sub_expression(lexer, gen, err);
- }
-
- int l2_parse_program(
- struct l2_lexer *lexer, struct l2_generator *gen, struct l2_parse_error *err) {
- l2_lexer_skip_opt(lexer, L2_TOK_EOL);
-
- int first = 1;
- 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;
- }
-
- l2_lexer_skip_opt(lexer, L2_TOK_EOL);
- first = 0;
- }
-
- l2_gen_halt(gen);
- l2_gen_flush(gen);
- return 0;
- }
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