guillm/42sh
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

fix(parser + lexer): interaction -- WIP

Browse source
This commit is contained in:
Matteo Flebus 2026-01-16 19:31:58 +01:00
parent 04529f858c
commit 10ce140e37
5 changed files with 99 additions and 48 deletions
Download patch file Download diff file Expand all files Collapse all files

65
src/lexer/lexer.c
View file

@ -13,16 +13,40 @@
static char *end_last_token;
static ssize_t remaining_chars;
static bool at_beginning = true;
static struct token *last_token;
static struct token *current_token;
/* @brief: saves state for the next call the the lexer.
/* @brief: sets the current_token to [tok].
* this function is called by token_peek().
*/
static void update_current_token(struct token* tok)
{
current_token = tok;
}
/* @brief: frees the last token and sets it to [tok].
* Also sets current_token to NULL.
* this function is called by token_pop().
*
*/
static void save_state(char *stream, ssize_t i)
static void update_last_token(struct token* tok)
{
free_token(&last_token);
last_token = tok;
}
/* @brief: saves state for the next call to the the lexer.
* this function is called by token_pop().
*
*/
static void save_state(char *stream, ssize_t i, struct token *tok)
{
remaining_chars -= i;
end_last_token = stream + i;
at_beginning = false;
return;
update_last_token(tok);
}
/* @return: true if a special character from the grammar was found,
@ -67,7 +91,7 @@ static void set_token_spechar(struct token *tok, char *begin, ssize_t size)
*/
static void set_token_keyword(struct token *tok, char *begin, ssize_t size)
{
if (tok->type != TOKEN_NULL)
if (tok->type != TOKEN_NULL || size == 0)
return;
if (strncmp(begin, "if", size) == 0)
{
@ -101,7 +125,7 @@ static void set_token_keyword(struct token *tok, char *begin, ssize_t size)
*/
static void set_token_word(struct token *tok, char *begin, ssize_t size)
{
if (tok->type == TOKEN_NULL)
if (tok->type == TOKEN_NULL && size != 0)
{
tok->type = TOKEN_WORD;
tok->data = calloc(size + 1, sizeof(char));
@ -124,13 +148,14 @@ struct token *new_token(char *begin, ssize_t size)
return tok;
}
void free_token(struct token *tok)
void free_token(struct token **tok)
{
if (tok == NULL)
if (tok == NULL || *tok == NULL)
return;
if (tok->data != NULL)
free(tok->data);
free(tok);
if ((*tok)->data != NULL)
free((*tok)->data);
free(*tok);
*tok = NULL;
}
char *stream_init(void)
@ -156,6 +181,12 @@ char *stream_init(void)
struct token *peek_token(void)
{
// EOF looping mode
if (current_token != NULL && current_token->type == TOKEN_EOF)
{
return current_token;
}
char *stream = stream_init();
ssize_t i = 0;
@ -175,11 +206,18 @@ struct token *peek_token(void)
i++;
}
return new_token(stream, i);
struct token *tok = new_token(stream, i);
update_current_token(tok);
return tok;
}
struct token *pop_token(void)
{
if (last_token != NULL && last_token->type == TOKEN_EOF)
{
free_token(&last_token);
return NULL;
}
char *stream = stream_init();
ssize_t i = 0;
@ -199,7 +237,8 @@ struct token *pop_token(void)
i++;
}
save_state(stream, i);
struct token *tok = new_token(stream, i);
save_state(stream, i, tok);
return new_token(stream, i);
return tok;
}

9
src/lexer/lexer.h
View file

@ -26,7 +26,8 @@ struct token
/*
* @brief: returns the next (newly allocated) token without consuming it.
* if end of input is reached, returns a token of type TOKEN_EOF.
* if end of input is reached, enters in EOF looping node,
* returning only the same token of type TOKEN_EOF.
*
*/
struct token *peek_token(void);
@ -34,6 +35,10 @@ struct token *peek_token(void);
/*
* @brief: returns the next (newly allocated) token and consumes it.
* if end of input is reached, returns a token of type TOKEN_EOF.
* It also frees the last token created if there was one.
* @warning: if the last returned token was a token EOF, it frees it
* and returns NULL. This means that after peeking a token EOF
* in the parser, there must be EXACTLY ONE call to pop_token().
*
*/
struct token *pop_token(void);
@ -58,7 +63,7 @@ struct token *new_token(char *begin, ssize_t size);
/* @brief: frees the token given in argument
*
*/
void free_token(struct token *tok);
void free_token(struct token **tok);
/*
* @brief: checks if the stream used for the last token creation is empty.

34
src/parser/parser.c
View file

@ -17,33 +17,39 @@
struct ast *get_ast()
{
struct list *result_list = NULL;
struct ast *current_node = NULL;
// struct list *result_list = NULL;
// struct ast *current_node = NULL;
struct token *token = peek_token();
struct token *token = PEEK_TOKEN();
while (token != NULL && token->type != TOKEN_EOF)
if (token->type == TOKEN_EOF)
{
switch (token->type)
{
case TOKEN_WORD:
token = pop_token();
// TODO
// return ast END.
}
else if (token->type == TOKEN_NEWLINE)
{
token = pop_token();
// TODO
// return ast EMPTY.
}
else // TOKEN WORD
{
// TODO
// call parse_list
current_node = parse_simple_command();
result_list = list_append(result_list, current_node);
break;
default:
// Forward
token = pop_token();
break;
}
token = peek_token();
}
/*
if (token == NULL)
{
puts("Internal error: cannot get the following token");
puts("Hint: EOF might be missing");
return NULL;
}
*/
struct ast *result = ast_create_list(result_list);
return result;

18
src/parser/parser.h
View file

@ -3,6 +3,24 @@
#include "utils/ast/ast.h"
// === Macros
#define PEEK_TOKEN() \
peek_token(); \
if (token == NULL) \
{ \
puts("Internal error: cannot get the following token"); \
return NULL; \
}
#define POP_TOKEN() \
pop_token(); \
if (token == NULL) \
{ \
puts("Internal error: cannot get the following token"); \
return NULL; \
}
/* @brief Builds the AST representation of the next command to execute.
*
* @return Returns the AST representation of the next command to execute.

21
src/parser/parsing_utils.c
View file

@ -8,24 +8,6 @@
#include "lexer/lexer.h"
#include "utils/ast/ast.h"
// === Macros
#define PEEK_TOKEN() \
peek_token(); \
if (token == NULL) \
{ \
puts("Internal error: cannot get the following token"); \
return NULL; \
}
#define POP_TOKEN() \
pop_token(); \
if (token == NULL) \
{ \
puts("Internal error: cannot get the following token"); \
return NULL; \
}
// === Static functions
/* Returns true if c is a command terminator, false otherwise
@ -58,8 +40,9 @@ struct ast *parse_simple_command(void)
while (!isterminator(token))
{
command_elements = list_append(command_elements, token->data);
token = POP_TOKEN();
command_elements = list_append(command_elements, token->data);
token = PEEK_TOKEN();
}
struct ast *result = ast_create_command(command_elements);