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#include "parser.h"
#include "lexer.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define PARSER_PANIC(format, ...) {\
fprintf(\
stderr,\
"ccc: parse error: %s: line %lu, column %lu: " format "\n",\
tok.PATH,\
tok.LINE,\
tok.COL __VA_OPT__(,)\
__VA_ARGS__);\
exit(1);\
}
static struct token tok;
static void* protected_alloc(size_t sz) {
void* ptr = calloc(1, sz);
if (ptr == NULL) {
fprintf(stderr, "ccc: out of memory\n");
exit(1);
}
return ptr;
}
static void unexpected_token(enum token_type expected) {
/* TODO: print what token was expected */
PARSER_PANIC("unexpected token");
}
static void expect(enum token_type expected) {
if (!lexer_pop(&tok))
PARSER_PANIC("unexpected EOF");
if (tok.type != expected) unexpected_token(expected);
}
/* "handle" indicates that we've peeked already */
static void handle_expr(struct expr_node* p_node);
static void handle_stmt(struct stmt_node* p_node);
static void parse_type(struct type_node* p_node) {
expect(TK_IDENT);
/* TODO: maybe check that this type is real haha */
p_node->type = tok.data.ident;
}
static void parse_return(struct return_node* p_node) {
expect(TK_IDENT);
if (strcmp(tok.data.ident, "return") != 0)
PARSER_PANIC("unexpected token %s; expected: return", tok.data.ident);
if (!lexer_peek(&tok))
PARSER_PANIC("unexpected EOF in return statement");
if (tok.type == TK_SEMI) {
p_node->ret_val = NULL;
return;
}
p_node->ret_val = protected_alloc(sizeof(struct expr_node));
handle_expr(p_node->ret_val);
}
static void parse_int_lit(struct int_lit_node* p_node) {
expect(TK_INT_LIT);
p_node->val = tok.data.int_lit;
}
static void handle_expr(struct expr_node* p_node) {
switch (tok.type) {
case TK_SEMI:
p_node->type = EXPR_EMPTY;
return;
case TK_INT_LIT:
p_node->type = EXPR_INT_LIT;
parse_int_lit(&p_node->as._int_lit);
return;
default:
PARSER_PANIC("expected expression");
}
}
static void parse_var_decl(struct var_decl_node* p_node) {
parse_type(&p_node->type);
expect(TK_IDENT);
p_node->ident = tok.data.ident;
}
static void parse_group(struct group_node* p_node) {
expect(TK_LCURLY);
struct stmt_node** pp_node = &p_node->body_head;
for (;;) {
if (!lexer_peek(&tok))
PARSER_PANIC("unexpected EOF in statement group");
if (tok.type == TK_RCURLY) break;
*pp_node = protected_alloc(sizeof(struct stmt_node));
handle_stmt(*pp_node);
pp_node = &((*pp_node)->next);
}
expect(TK_RCURLY);
}
static void handle_stmt(struct stmt_node* p_node) {
switch (tok.type) {
case TK_LCURLY:
p_node->type = STMT_GROUP;
parse_group(&p_node->as._group);
return;
case TK_IDENT:
if (strcmp(tok.data.ident, "return") == 0) {
p_node->type = STMT_RETURN;
parse_return(&p_node->as._return);
} else {
p_node->type = STMT_VAR_DECL;
parse_var_decl(&p_node->as._var_decl);
}
break;
default:
p_node->type = STMT_EXPR;
handle_expr(&p_node->as._expr);
}
expect(TK_SEMI);
}
static void parse_arg_list(struct var_decl_node** pp_arg) {
for (;;) {
*pp_arg = protected_alloc(sizeof(struct var_decl_node));
parse_var_decl(*pp_arg);
pp_arg = &((*pp_arg)->next);
if (!lexer_peek(&tok))
PARSER_PANIC("unexpected EOF in argument list");
if (tok.type == TK_RPAREN) break;
expect(TK_COMMA);
}
}
static void parse_fn_decl(struct fn_decl_node* p_node) {
parse_type(&p_node->return_type);
expect(TK_IDENT);
p_node->name = tok.data.ident;
expect(TK_LPAREN);
if (!lexer_peek(&tok))
PARSER_PANIC("unexpected EOF in function declaration");
if (tok.type != TK_RPAREN) parse_arg_list(&p_node->args_head);
expect(TK_RPAREN);
parse_group(&p_node->body);
}
static bool parse_root(struct root_node* p_node) {
if (!lexer_peek(&tok)) return false;
p_node->type = ROOT_FN_DECL;
parse_fn_decl(&p_node->as._fn_decl);
return true;
}
struct root_node* parse(const char* path) {
lexer_load(path);
struct root_node* root;
struct root_node** p_node = &root;
for (;;) {
*p_node = protected_alloc(sizeof(struct root_node));
if (!parse_root(*p_node)) {
free(*p_node);
*p_node = NULL;
break;
}
p_node = &((*p_node)->next);
}
lexer_close();
return root;
}
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