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gh-102856: Clean some of the PEP 701 tokenizer implementation #103634

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Apr 19, 2023
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gh-102856: Clean some of the PEP 701 tokenizer implementation #103634

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917ba81
gh-102856: Clean some of the PEP 701 tokenizer implementation
pablogsal Apr 19, 2023
a377562
fixup! gh-102856: Clean some of the PEP 701 tokenizer implementation
pablogsal Apr 19, 2023
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136 changes: 65 additions & 71 deletions Parser/tokenizer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11,11 +11,6 @@
#include "tokenizer.h"
#include "errcode.h"

#include "unicodeobject.h"
#include "bytesobject.h"
#include "fileobject.h"
#include "abstract.h"

/* Alternate tab spacing */
#define ALTTABSIZE 1

Expand Down Expand Up @@ -43,6 +38,8 @@
tok->lineno++; \
tok->col_offset = 0;

#define INSIDE_FSTRING(tok) (tok->tok_mode_stack_index > 0)
#define INSIDE_FSTRING_EXPR(tok) (tok->curly_bracket_expr_start_depth >= 0)
#ifdef Py_DEBUG
static inline tokenizer_mode* TOK_GET_MODE(struct tok_state* tok) {
assert(tok->tok_mode_stack_index >= 0);
Expand All @@ -54,15 +51,9 @@ static inline tokenizer_mode* TOK_NEXT_MODE(struct tok_state* tok) {
assert(tok->tok_mode_stack_index < MAXLEVEL);
return &(tok->tok_mode_stack[++tok->tok_mode_stack_index]);
}
static inline int *TOK_GET_BRACKET_MARK(tokenizer_mode* mode) {
assert(mode->bracket_mark_index >= 0);
assert(mode->bracket_mark_index < MAX_EXPR_NESTING);
return &(mode->bracket_mark[mode->bracket_mark_index]);
}
#else
#define TOK_GET_MODE(tok) (&(tok->tok_mode_stack[tok->tok_mode_stack_index]))
#define TOK_NEXT_MODE(tok) (&(tok->tok_mode_stack[++tok->tok_mode_stack_index]))
#define TOK_GET_BRACKET_MARK(mode) (&(mode->bracket_mark[mode->bracket_mark_index]))
#endif

/* Forward */
Expand Down Expand Up @@ -398,20 +389,7 @@ update_fstring_expr(struct tok_state *tok, char cur)
tokenizer_mode *tok_mode = TOK_GET_MODE(tok);

switch (cur) {
case '{':
if (tok_mode->last_expr_buffer != NULL) {
PyMem_Free(tok_mode->last_expr_buffer);
}
tok_mode->last_expr_buffer = PyMem_Malloc(size);
if (tok_mode->last_expr_buffer == NULL) {
tok->done = E_NOMEM;
return 0;
}
tok_mode->last_expr_size = size;
tok_mode->last_expr_end = -1;
strncpy(tok_mode->last_expr_buffer, tok->cur, size);
break;
case 0:
case 0:
if (!tok_mode->last_expr_buffer || tok_mode->last_expr_end >= 0) {
return 1;
}
Expand All @@ -421,23 +399,38 @@ update_fstring_expr(struct tok_state *tok, char cur)
);
if (new_buffer == NULL) {
PyMem_Free(tok_mode->last_expr_buffer);
tok->done = E_NOMEM;
return 0;
goto error;
}
tok_mode->last_expr_buffer = new_buffer;
strncpy(tok_mode->last_expr_buffer + tok_mode->last_expr_size, tok->cur, size);
tok_mode->last_expr_size += size;
break;
case '{':
if (tok_mode->last_expr_buffer != NULL) {
PyMem_Free(tok_mode->last_expr_buffer);
}
tok_mode->last_expr_buffer = PyMem_Malloc(size);
if (tok_mode->last_expr_buffer == NULL) {
goto error;
}
tok_mode->last_expr_size = size;
tok_mode->last_expr_end = -1;
strncpy(tok_mode->last_expr_buffer, tok->cur, size);
break;
case '}':
case '!':
case ':':
if (tok_mode->last_expr_end == -1) {
tok_mode->last_expr_end = strlen(tok->start);
}
break;
default:
Py_UNREACHABLE();
}

return 1;
error:
tok->done = E_NOMEM;
return 0;
}

static void
Expand Down Expand Up @@ -1766,7 +1759,7 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
/* Skip comment, unless it's a type comment */
if (c == '#') {

if (tok->tok_mode_stack_index > 0) {
if (INSIDE_FSTRING(tok)) {
return MAKE_TOKEN(syntaxerror(tok, "f-string expression part cannot include '#'"));
}

Expand Down Expand Up @@ -2208,32 +2201,31 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t

p_start = tok->start;
p_end = tok->cur;
tokenizer_mode *current_tok = TOK_NEXT_MODE(tok);
current_tok->kind = TOK_FSTRING_MODE;
current_tok->f_string_quote = quote;
current_tok->f_string_quote_size = quote_size;
current_tok->f_string_start = tok->start;
current_tok->f_string_multi_line_start = tok->line_start;
current_tok->last_expr_buffer = NULL;
current_tok->last_expr_size = 0;
current_tok->last_expr_end = -1;
tokenizer_mode *the_current_tok = TOK_NEXT_MODE(tok);
the_current_tok->kind = TOK_FSTRING_MODE;
the_current_tok->f_string_quote = quote;
the_current_tok->f_string_quote_size = quote_size;
the_current_tok->f_string_start = tok->start;
the_current_tok->f_string_multi_line_start = tok->line_start;
the_current_tok->last_expr_buffer = NULL;
the_current_tok->last_expr_size = 0;
the_current_tok->last_expr_end = -1;

switch (*tok->start) {
case 'F':
case 'f':
current_tok->f_string_raw = tolower(*(tok->start + 1)) == 'r';
the_current_tok->f_string_raw = tolower(*(tok->start + 1)) == 'r';
break;
case 'R':
case 'r':
current_tok->f_string_raw = 1;
the_current_tok->f_string_raw = 1;
break;
default:
Py_UNREACHABLE();
}

current_tok->bracket_stack = 0;
current_tok->bracket_mark[0] = 0;
current_tok->bracket_mark_index = -1;
the_current_tok->curly_bracket_depth = 0;
the_current_tok->curly_bracket_expr_start_depth = -1;
return MAKE_TOKEN(FSTRING_START);
}

Expand Down Expand Up @@ -2282,15 +2274,15 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
int start = tok->lineno;
tok->lineno = tok->first_lineno;

if (tok->tok_mode_stack_index > 0) {
if (INSIDE_FSTRING(tok)) {
/* When we are in an f-string, before raising the
* unterminated string literal error, check whether
* does the initial quote matches with f-strings quotes
* and if it is, then this must be a missing '}' token
* so raise the proper error */
tokenizer_mode *current_tok = TOK_GET_MODE(tok);
if (current_tok->f_string_quote == quote &&
current_tok->f_string_quote_size == quote_size) {
tokenizer_mode *the_current_tok = TOK_GET_MODE(tok);
if (the_current_tok->f_string_quote == quote &&
the_current_tok->f_string_quote_size == quote_size) {
return MAKE_TOKEN(syntaxerror(tok, "f-string: expecting '}'", start));
}
}
Expand Down Expand Up @@ -2339,18 +2331,17 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t

/* Punctuation character */
int is_punctuation = (c == ':' || c == '}' || c == '!' || c == '{');
if (is_punctuation && tok->tok_mode_stack_index > 0 && current_tok->bracket_mark_index >= 0) {
int mark = *TOK_GET_BRACKET_MARK(current_tok);
/* This code block gets executed before the bracket_stack is incremented
if (is_punctuation && INSIDE_FSTRING(tok) && INSIDE_FSTRING_EXPR(current_tok)) {
/* This code block gets executed before the curly_bracket_depth is incremented
* by the `{` case, so for ensuring that we are on the 0th level, we need
* to adjust it manually */
int cursor = current_tok->bracket_stack - (c != '{');
int cursor = current_tok->curly_bracket_depth - (c != '{');

if (cursor == 0 && !update_fstring_expr(tok, c)) {
return MAKE_TOKEN(ENDMARKER);
}

if (c == ':' && cursor == mark) {
if (c == ':' && cursor == current_tok->curly_bracket_expr_start_depth) {
current_tok->kind = TOK_FSTRING_MODE;
p_start = tok->start;
p_end = tok->cur;
Expand Down Expand Up @@ -2390,16 +2381,15 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
tok->parenlinenostack[tok->level] = tok->lineno;
tok->parencolstack[tok->level] = (int)(tok->start - tok->line_start);
tok->level++;

if (tok->tok_mode_stack_index > 0) {
current_tok->bracket_stack++;
if (INSIDE_FSTRING(tok)) {
current_tok->curly_bracket_depth++;
}
break;
case ')':
case ']':
case '}':
if (!tok->level) {
if (tok->tok_mode_stack_index > 0 && !current_tok->bracket_stack && c == '}') {
if (INSIDE_FSTRING(tok) && !current_tok->curly_bracket_depth && c == '}') {
return MAKE_TOKEN(syntaxerror(tok, "f-string: single '}' is not allowed"));
}
return MAKE_TOKEN(syntaxerror(tok, "unmatched '%c'", c));
Expand All @@ -2415,10 +2405,10 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
nested expression, then instead of matching a different
syntactical construct with it; we'll throw an unmatched
parentheses error. */
if (tok->tok_mode_stack_index > 0 && opening == '{') {
assert(current_tok->bracket_stack >= 0);
int previous_bracket = current_tok->bracket_stack - 1;
if (previous_bracket == *TOK_GET_BRACKET_MARK(current_tok)) {
if (INSIDE_FSTRING(tok) && opening == '{') {
assert(current_tok->curly_bracket_depth >= 0);
int previous_bracket = current_tok->curly_bracket_depth - 1;
if (previous_bracket == current_tok->curly_bracket_expr_start_depth) {
return MAKE_TOKEN(syntaxerror(tok, "f-string: unmatched '%c'", c));
}
}
Expand All @@ -2436,14 +2426,16 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
}
}

if (tok->tok_mode_stack_index > 0) {
current_tok->bracket_stack--;
if (c == '}' && current_tok->bracket_stack == *TOK_GET_BRACKET_MARK(current_tok)) {
current_tok->bracket_mark_index--;
if (INSIDE_FSTRING(tok)) {
current_tok->curly_bracket_depth--;
if (c == '}' && current_tok->curly_bracket_depth == current_tok->curly_bracket_expr_start_depth) {
current_tok->curly_bracket_expr_start_depth--;
current_tok->kind = TOK_FSTRING_MODE;
}
}
break;
default:
break;
}

if (!Py_UNICODE_ISPRINTABLE(c)) {
Expand Down Expand Up @@ -2479,11 +2471,10 @@ tok_get_fstring_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct

if ((start_char == '{' && peek1 != '{') || (start_char == '}' && peek1 != '}')) {
if (start_char == '{') {
current_tok->bracket_mark_index++;
if (current_tok->bracket_mark_index >= MAX_EXPR_NESTING) {
current_tok->curly_bracket_expr_start_depth++;
if (current_tok->curly_bracket_expr_start_depth >= MAX_EXPR_NESTING) {
return MAKE_TOKEN(syntaxerror(tok, "f-string: expressions nested too deeply"));
}
*TOK_GET_BRACKET_MARK(current_tok) = current_tok->bracket_stack;
}
TOK_GET_MODE(tok)->kind = TOK_REGULAR_MODE;
return tok_get_normal_mode(tok, current_tok, token);
Expand Down Expand Up @@ -2544,17 +2535,20 @@ tok_get_fstring_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct
end_quote_size = 0;
}

int in_format_spec = current_tok->last_expr_end != -1 && current_tok->bracket_mark_index >= 0;
int in_format_spec = (
current_tok->last_expr_end != -1
&&
INSIDE_FSTRING_EXPR(current_tok)
);
if (c == '{') {
int peek = tok_nextc(tok);
if (peek != '{' || in_format_spec) {
tok_backup(tok, peek);
tok_backup(tok, c);
current_tok->bracket_mark_index++;
if (current_tok->bracket_mark_index >= MAX_EXPR_NESTING) {
current_tok->curly_bracket_expr_start_depth++;
if (current_tok->curly_bracket_expr_start_depth >= MAX_EXPR_NESTING) {
return MAKE_TOKEN(syntaxerror(tok, "f-string: expressions nested too deeply"));
}
*TOK_GET_BRACKET_MARK(current_tok) = current_tok->bracket_stack;
TOK_GET_MODE(tok)->kind = TOK_REGULAR_MODE;
p_start = tok->start;
p_end = tok->cur;
Expand Down
5 changes: 2 additions & 3 deletions Parser/tokenizer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -43,9 +43,8 @@ enum tokenizer_mode_kind_t {
typedef struct _tokenizer_mode {
enum tokenizer_mode_kind_t kind;

int bracket_stack;
int bracket_mark[MAX_EXPR_NESTING];
int bracket_mark_index;
int curly_bracket_depth;
int curly_bracket_expr_start_depth;

char f_string_quote;
int f_string_quote_size;
Expand Down