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04b9147e15
circuitpython/py/lexer.c
Damien George 04b9147e15 Add license header to (almost) all files. 
Blanket wide to all .c and .h files.  Some files originating from ST are
difficult to deal with (license wise) so it was left out of those.

Also merged modpyb.h, modos.h, modstm.h and modtime.h in stmhal/.
2014-05-03 23:27:38 +01:00

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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/* lexer.c -- simple tokeniser for Python implementation
*/
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <assert.h>
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "lexer.h"
#define TAB_SIZE (8)
// TODO seems that CPython allows NULL byte in the input stream
// don't know if that's intentional or not, but we don't allow it
struct _mp_lexer_t {
qstr source_name; // name of source
void *stream_data; // data for stream
mp_lexer_stream_next_char_t stream_next_char; // stream callback to get next char
mp_lexer_stream_close_t stream_close; // stream callback to free
unichar chr0, chr1, chr2; // current cached characters from source
uint line; // source line
uint column; // source column
int emit_dent; // non-zero when there are INDENT/DEDENT tokens to emit
int nested_bracket_level; // >0 when there are nested brackets over multiple lines
uint alloc_indent_level;
uint num_indent_level;
uint16_t *indent_level;
vstr_t vstr;
mp_token_t tok_cur;
};
// TODO replace with a call to a standard function
bool str_strn_equal(const char *str, const char *strn, int len) {
uint i = 0;
while (i < len && *str == *strn) {
++i;
++str;
++strn;
}
return i == len && *str == 0;
}
#ifdef MICROPY_DEBUG_PRINTERS
void mp_token_show(const mp_token_t *tok) {
printf("(%d:%d) kind:%d str:%p len:%d", tok->src_line, tok->src_column, tok->kind, tok->str, tok->len);
if (tok->str != NULL && tok->len > 0) {
const char *i = tok->str;
const char *j = i + tok->len;
printf(" ");
while (i < j) {
unichar c = utf8_get_char(i);
i = utf8_next_char(i);
if (unichar_isprint(c)) {
printf("%c", c);
} else {
printf("?");
}
}
}
printf("\n");
}
#endif
#define CUR_CHAR(lex) ((lex)->chr0)
STATIC bool is_end(mp_lexer_t *lex) {
return lex->chr0 == MP_LEXER_CHAR_EOF;
}
STATIC bool is_physical_newline(mp_lexer_t *lex) {
return lex->chr0 == '\n' || lex->chr0 == '\r';
}
STATIC bool is_char(mp_lexer_t *lex, char c) {
return lex->chr0 == c;
}
STATIC bool is_char_or(mp_lexer_t *lex, char c1, char c2) {
return lex->chr0 == c1 || lex->chr0 == c2;
}
STATIC bool is_char_or3(mp_lexer_t *lex, char c1, char c2, char c3) {
return lex->chr0 == c1 || lex->chr0 == c2 || lex->chr0 == c3;
}
/*
STATIC bool is_char_following(mp_lexer_t *lex, char c) {
return lex->chr1 == c;
}
*/
STATIC bool is_char_following_or(mp_lexer_t *lex, char c1, char c2) {
return lex->chr1 == c1 || lex->chr1 == c2;
}
STATIC bool is_char_following_following_or(mp_lexer_t *lex, char c1, char c2) {
return lex->chr2 == c1 || lex->chr2 == c2;
}
STATIC bool is_char_and(mp_lexer_t *lex, char c1, char c2) {
return lex->chr0 == c1 && lex->chr1 == c2;
}
STATIC bool is_whitespace(mp_lexer_t *lex) {
return unichar_isspace(lex->chr0);
}
STATIC bool is_letter(mp_lexer_t *lex) {
return unichar_isalpha(lex->chr0);
}
STATIC bool is_digit(mp_lexer_t *lex) {
return unichar_isdigit(lex->chr0);
}
STATIC bool is_following_digit(mp_lexer_t *lex) {
return unichar_isdigit(lex->chr1);
}
STATIC bool is_following_odigit(mp_lexer_t *lex) {
return lex->chr1 >= '0' && lex->chr1 <= '7';
}
// TODO UNICODE include unicode characters in definition of identifiers
STATIC bool is_head_of_identifier(mp_lexer_t *lex) {
return is_letter(lex) || lex->chr0 == '_';
}
// TODO UNICODE include unicode characters in definition of identifiers
STATIC bool is_tail_of_identifier(mp_lexer_t *lex) {
return is_head_of_identifier(lex) || is_digit(lex);
}
STATIC void next_char(mp_lexer_t *lex) {
if (lex->chr0 == MP_LEXER_CHAR_EOF) {
return;
}
int advance = 1;
if (lex->chr0 == '\n') {
// LF is a new line
++lex->line;
lex->column = 1;
} else if (lex->chr0 == '\r') {
// CR is a new line
++lex->line;
lex->column = 1;
if (lex->chr1 == '\n') {
// CR LF is a single new line
advance = 2;
}
} else if (lex->chr0 == '\t') {
// a tab
lex->column = (((lex->column - 1 + TAB_SIZE) / TAB_SIZE) * TAB_SIZE) + 1;
} else {
// a character worth one column
++lex->column;
}
for (; advance > 0; advance--) {
lex->chr0 = lex->chr1;
lex->chr1 = lex->chr2;
lex->chr2 = lex->stream_next_char(lex->stream_data);
if (lex->chr2 == MP_LEXER_CHAR_EOF) {
// EOF
if (lex->chr1 != MP_LEXER_CHAR_EOF && lex->chr1 != '\n' && lex->chr1 != '\r') {
lex->chr2 = '\n'; // insert newline at end of file
}
}
}
}
void indent_push(mp_lexer_t *lex, uint indent) {
if (lex->num_indent_level >= lex->alloc_indent_level) {
lex->indent_level = m_renew(uint16_t, lex->indent_level, lex->alloc_indent_level, lex->alloc_indent_level * 2);
lex->alloc_indent_level *= 2;
}
lex->indent_level[lex->num_indent_level++] = indent;
}
uint indent_top(mp_lexer_t *lex) {
return lex->indent_level[lex->num_indent_level - 1];
}
void indent_pop(mp_lexer_t *lex) {
lex->num_indent_level -= 1;
}
// some tricky operator encoding:
// <op> = begin with <op>, if this opchar matches then begin here
// e<op> = end with <op>, if this opchar matches then end
// E<op> = mandatory end with <op>, this opchar must match, then end
// c<op> = continue with <op>, if this opchar matches then continue matching
// this means if the start of two ops are the same then they are equal til the last char
STATIC const char *tok_enc =
"()[]{},:;@~" // singles
"<e=c<e=" // < <= << <<=
">e=c>e=" // > >= >> >>=
"*e=c*e=" // * *= ** **=
"+e=" // + +=
"-e=e>" // - -= ->
"&e=" // & &=
"|e=" // | |=
"/e=c/e=" // / /= // //=
"%e=" // % %=
"^e=" // ^ ^=
"=e=" // = ==
"!E="; // !=
// TODO static assert that number of tokens is less than 256 so we can safely make this table with byte sized entries
STATIC const uint8_t tok_enc_kind[] = {
MP_TOKEN_DEL_PAREN_OPEN, MP_TOKEN_DEL_PAREN_CLOSE,
MP_TOKEN_DEL_BRACKET_OPEN, MP_TOKEN_DEL_BRACKET_CLOSE,
MP_TOKEN_DEL_BRACE_OPEN, MP_TOKEN_DEL_BRACE_CLOSE,
MP_TOKEN_DEL_COMMA, MP_TOKEN_DEL_COLON, MP_TOKEN_DEL_SEMICOLON, MP_TOKEN_DEL_AT, MP_TOKEN_OP_TILDE,
MP_TOKEN_OP_LESS, MP_TOKEN_OP_LESS_EQUAL, MP_TOKEN_OP_DBL_LESS, MP_TOKEN_DEL_DBL_LESS_EQUAL,
MP_TOKEN_OP_MORE, MP_TOKEN_OP_MORE_EQUAL, MP_TOKEN_OP_DBL_MORE, MP_TOKEN_DEL_DBL_MORE_EQUAL,
MP_TOKEN_OP_STAR, MP_TOKEN_DEL_STAR_EQUAL, MP_TOKEN_OP_DBL_STAR, MP_TOKEN_DEL_DBL_STAR_EQUAL,
MP_TOKEN_OP_PLUS, MP_TOKEN_DEL_PLUS_EQUAL,
MP_TOKEN_OP_MINUS, MP_TOKEN_DEL_MINUS_EQUAL, MP_TOKEN_DEL_MINUS_MORE,
MP_TOKEN_OP_AMPERSAND, MP_TOKEN_DEL_AMPERSAND_EQUAL,
MP_TOKEN_OP_PIPE, MP_TOKEN_DEL_PIPE_EQUAL,
MP_TOKEN_OP_SLASH, MP_TOKEN_DEL_SLASH_EQUAL, MP_TOKEN_OP_DBL_SLASH, MP_TOKEN_DEL_DBL_SLASH_EQUAL,
MP_TOKEN_OP_PERCENT, MP_TOKEN_DEL_PERCENT_EQUAL,
MP_TOKEN_OP_CARET, MP_TOKEN_DEL_CARET_EQUAL,
MP_TOKEN_DEL_EQUAL, MP_TOKEN_OP_DBL_EQUAL,
MP_TOKEN_OP_NOT_EQUAL,
};
// must have the same order as enum in lexer.h
STATIC const char *tok_kw[] = {
"False",
"None",
"True",
"and",
"as",
"assert",
"break",
"class",
"continue",
"def",
"del",
"elif",
"else",
"except",
"finally",
"for",
"from",
"global",
"if",
"import",
"in",
"is",
"lambda",
"nonlocal",
"not",
"or",
"pass",
"raise",
"return",
"try",
"while",
"with",
"yield",
NULL,
};
STATIC int hex_digit(unichar c) {
// c is assumed to be hex digit
int n = c - '0';
if (n > 9) {
n &= ~('a' - 'A');
n -= ('A' - ('9' + 1));
}
return n;
}
// This is called with CUR_CHAR() before first hex digit, and should return with
// it pointing to last hex digit
STATIC bool get_hex(mp_lexer_t *lex, int num_digits, uint *result) {
uint num = 0;
while (num_digits-- != 0) {
next_char(lex);
unichar c = CUR_CHAR(lex);
if (!unichar_isxdigit(c)) {
return false;
}
num = (num << 4) + hex_digit(c);
}
*result = num;
return true;
}
STATIC void mp_lexer_next_token_into(mp_lexer_t *lex, mp_token_t *tok, bool first_token) {
// skip white space and comments
bool had_physical_newline = false;
while (!is_end(lex)) {
if (is_physical_newline(lex)) {
had_physical_newline = true;
next_char(lex);
} else if (is_whitespace(lex)) {
next_char(lex);
} else if (is_char(lex, '#')) {
next_char(lex);
while (!is_end(lex) && !is_physical_newline(lex)) {
next_char(lex);
}
// had_physical_newline will be set on next loop
} else if (is_char(lex, '\\')) {
// backslash (outside string literals) must appear just before a physical newline
next_char(lex);
if (!is_physical_newline(lex)) {
// SyntaxError: unexpected character after line continuation character
tok->src_line = lex->line;
tok->src_column = lex->column;
tok->kind = MP_TOKEN_BAD_LINE_CONTINUATION;
vstr_reset(&lex->vstr);
tok->str = vstr_str(&lex->vstr);
tok->len = 0;
return;
} else {
next_char(lex);
}
} else {
break;
}
}
// set token source information
tok->src_line = lex->line;
tok->src_column = lex->column;
// start new token text
vstr_reset(&lex->vstr);
if (first_token && lex->line == 1 && lex->column != 1) {
// check that the first token is in the first column
// if first token is not on first line, we get a physical newline and
// this check is done as part of normal indent/dedent checking below
// (done to get equivalence with CPython)
tok->kind = MP_TOKEN_INDENT;
} else if (lex->emit_dent < 0) {
tok->kind = MP_TOKEN_DEDENT;
lex->emit_dent += 1;
} else if (lex->emit_dent > 0) {
tok->kind = MP_TOKEN_INDENT;
lex->emit_dent -= 1;
} else if (had_physical_newline && lex->nested_bracket_level == 0) {
tok->kind = MP_TOKEN_NEWLINE;
uint num_spaces = lex->column - 1;
lex->emit_dent = 0;
if (num_spaces == indent_top(lex)) {
} else if (num_spaces > indent_top(lex)) {
indent_push(lex, num_spaces);
lex->emit_dent += 1;
} else {
while (num_spaces < indent_top(lex)) {
indent_pop(lex);
lex->emit_dent -= 1;
}
if (num_spaces != indent_top(lex)) {
tok->kind = MP_TOKEN_DEDENT_MISMATCH;
}
}
} else if (is_end(lex)) {
if (indent_top(lex) > 0) {
tok->kind = MP_TOKEN_NEWLINE;
lex->emit_dent = 0;
while (indent_top(lex) > 0) {
indent_pop(lex);
lex->emit_dent -= 1;
}
} else {
tok->kind = MP_TOKEN_END;
}
} else if (is_char_or(lex, '\'', '\"')
|| (is_char_or3(lex, 'r', 'u', 'b') && is_char_following_or(lex, '\'', '\"'))
|| ((is_char_and(lex, 'r', 'b') || is_char_and(lex, 'b', 'r')) && is_char_following_following_or(lex, '\'', '\"'))) {
// a string or bytes literal
// parse type codes
bool is_raw = false;
bool is_bytes = false;
if (is_char(lex, 'u')) {
next_char(lex);
} else if (is_char(lex, 'b')) {
is_bytes = true;
next_char(lex);
if (is_char(lex, 'r')) {
is_raw = true;
next_char(lex);
}
} else if (is_char(lex, 'r')) {
is_raw = true;
next_char(lex);
if (is_char(lex, 'b')) {
is_bytes = true;
next_char(lex);
}
}
// set token kind
if (is_bytes) {
tok->kind = MP_TOKEN_BYTES;
} else {
tok->kind = MP_TOKEN_STRING;
}
// get first quoting character
char quote_char = '\'';
if (is_char(lex, '\"')) {
quote_char = '\"';
}
next_char(lex);
// work out if it's a single or triple quoted literal
int num_quotes;
if (is_char_and(lex, quote_char, quote_char)) {
// triple quotes
next_char(lex);
next_char(lex);
num_quotes = 3;
} else {
// single quotes
num_quotes = 1;
}
// parse the literal
int n_closing = 0;
while (!is_end(lex) && (num_quotes > 1 || !is_char(lex, '\n')) && n_closing < num_quotes) {
if (is_char(lex, quote_char)) {
n_closing += 1;
vstr_add_char(&lex->vstr, CUR_CHAR(lex));
} else {
n_closing = 0;
if (is_char(lex, '\\')) {
next_char(lex);
unichar c = CUR_CHAR(lex);
if (is_raw) {
// raw strings allow escaping of quotes, but the backslash is also emitted
vstr_add_char(&lex->vstr, '\\');
} else {
switch (c) {
case MP_LEXER_CHAR_EOF: break; // TODO a proper error message?
case '\n': c = MP_LEXER_CHAR_EOF; break; // TODO check this works correctly (we are supposed to ignore it
case '\\': break;
case '\'': break;
case '"': break;
case 'a': c = 0x07; break;
case 'b': c = 0x08; break;
case 't': c = 0x09; break;
case 'n': c = 0x0a; break;
case 'v': c = 0x0b; break;
case 'f': c = 0x0c; break;
case 'r': c = 0x0d; break;
case 'x':
{
uint num = 0;
if (!get_hex(lex, 2, &num)) {
// TODO error message
assert(0);
}
c = num;
break;
}
case 'N': break; // TODO \N{name} only in strings
case 'u': break; // TODO \uxxxx only in strings
case 'U': break; // TODO \Uxxxxxxxx only in strings
default:
if (c >= '0' && c <= '7') {
// Octal sequence, 1-3 chars
int digits = 3;
int num = c - '0';
while (is_following_odigit(lex) && --digits != 0) {
next_char(lex);
num = num * 8 + (CUR_CHAR(lex) - '0');
}
c = num;
} else {
// unrecognised escape character; CPython lets this through verbatim as '\' and then the character
vstr_add_char(&lex->vstr, '\\');
}
break;
}
}
if (c != MP_LEXER_CHAR_EOF) {
vstr_add_char(&lex->vstr, c);
}
} else {
vstr_add_char(&lex->vstr, CUR_CHAR(lex));
}
}
next_char(lex);
}
// check we got the required end quotes
if (n_closing < num_quotes) {
tok->kind = MP_TOKEN_LONELY_STRING_OPEN;
}
// cut off the end quotes from the token text
vstr_cut_tail_bytes(&lex->vstr, n_closing);
} else if (is_head_of_identifier(lex)) {
tok->kind = MP_TOKEN_NAME;
// get first char
vstr_add_char(&lex->vstr, CUR_CHAR(lex));
next_char(lex);
// get tail chars
while (!is_end(lex) && is_tail_of_identifier(lex)) {
vstr_add_char(&lex->vstr, CUR_CHAR(lex));
next_char(lex);
}
} else if (is_digit(lex) || (is_char(lex, '.') && is_following_digit(lex))) {
tok->kind = MP_TOKEN_NUMBER;
// get first char
vstr_add_char(&lex->vstr, CUR_CHAR(lex));
next_char(lex);
// get tail chars
while (!is_end(lex)) {
if (is_char_or(lex, 'e', 'E')) {
vstr_add_char(&lex->vstr, 'e');
next_char(lex);
if (is_char(lex, '+') || is_char(lex, '-')) {
vstr_add_char(&lex->vstr, CUR_CHAR(lex));
next_char(lex);
}
} else if (is_letter(lex) || is_digit(lex) || is_char_or(lex, '_', '.')) {
vstr_add_char(&lex->vstr, CUR_CHAR(lex));
next_char(lex);
} else {
break;
}
}
} else if (is_char(lex, '.')) {
// special handling for . and ... operators, because .. is not a valid operator
// get first char
vstr_add_char(&lex->vstr, '.');
next_char(lex);
if (is_char_and(lex, '.', '.')) {
vstr_add_char(&lex->vstr, '.');
vstr_add_char(&lex->vstr, '.');
next_char(lex);
next_char(lex);
tok->kind = MP_TOKEN_ELLIPSIS;
} else {
tok->kind = MP_TOKEN_DEL_PERIOD;
}
} else {
// search for encoded delimiter or operator
const char *t = tok_enc;
uint tok_enc_index = 0;
for (; *t != 0 && !is_char(lex, *t); t += 1) {
if (*t == 'e' || *t == 'c') {
t += 1;
} else if (*t == 'E') {
tok_enc_index -= 1;
t += 1;
}
tok_enc_index += 1;
}
next_char(lex);
if (*t == 0) {
// didn't match any delimiter or operator characters
tok->kind = MP_TOKEN_INVALID;
} else {
// matched a delimiter or operator character
// get the maximum characters for a valid token
t += 1;
uint t_index = tok_enc_index;
for (;;) {
for (; *t == 'e'; t += 1) {
t += 1;
t_index += 1;
if (is_char(lex, *t)) {
next_char(lex);
tok_enc_index = t_index;
break;
}
}
if (*t == 'E') {
t += 1;
if (is_char(lex, *t)) {
next_char(lex);
tok_enc_index = t_index;
} else {
tok->kind = MP_TOKEN_INVALID;
goto tok_enc_no_match;
}
break;
}
if (*t == 'c') {
t += 1;
t_index += 1;
if (is_char(lex, *t)) {
next_char(lex);
tok_enc_index = t_index;
t += 1;
} else {
break;
}
} else {
break;
}
}
// set token kind
tok->kind = tok_enc_kind[tok_enc_index];
tok_enc_no_match:
// compute bracket level for implicit line joining
if (tok->kind == MP_TOKEN_DEL_PAREN_OPEN || tok->kind == MP_TOKEN_DEL_BRACKET_OPEN || tok->kind == MP_TOKEN_DEL_BRACE_OPEN) {
lex->nested_bracket_level += 1;
} else if (tok->kind == MP_TOKEN_DEL_PAREN_CLOSE || tok->kind == MP_TOKEN_DEL_BRACKET_CLOSE || tok->kind == MP_TOKEN_DEL_BRACE_CLOSE) {
lex->nested_bracket_level -= 1;
}
}
}
// point token text to vstr buffer
tok->str = vstr_str(&lex->vstr);
tok->len = vstr_len(&lex->vstr);
// check for keywords
if (tok->kind == MP_TOKEN_NAME) {
for (int i = 0; tok_kw[i] != NULL; i++) {
if (str_strn_equal(tok_kw[i], tok->str, tok->len)) {
tok->kind = MP_TOKEN_KW_FALSE + i;
break;
}
}
}
}
mp_lexer_t *mp_lexer_new(qstr src_name, void *stream_data, mp_lexer_stream_next_char_t stream_next_char, mp_lexer_stream_close_t stream_close) {
mp_lexer_t *lex = m_new(mp_lexer_t, 1);
lex->source_name = src_name;
lex->stream_data = stream_data;
lex->stream_next_char = stream_next_char;
lex->stream_close = stream_close;
lex->line = 1;
lex->column = 1;
lex->emit_dent = 0;
lex->nested_bracket_level = 0;
lex->alloc_indent_level = 16;
lex->num_indent_level = 1;
lex->indent_level = m_new(uint16_t, lex->alloc_indent_level);
lex->indent_level[0] = 0;
vstr_init(&lex->vstr, 32);
// preload characters
lex->chr0 = stream_next_char(stream_data);
lex->chr1 = stream_next_char(stream_data);
lex->chr2 = stream_next_char(stream_data);
// if input stream is 0, 1 or 2 characters long and doesn't end in a newline, then insert a newline at the end
if (lex->chr0 == MP_LEXER_CHAR_EOF) {
lex->chr0 = '\n';
} else if (lex->chr1 == MP_LEXER_CHAR_EOF) {
if (lex->chr0 != '\n' && lex->chr0 != '\r') {
lex->chr1 = '\n';
}
} else if (lex->chr2 == MP_LEXER_CHAR_EOF) {
if (lex->chr1 != '\n' && lex->chr1 != '\r') {
lex->chr2 = '\n';
}
}
// preload first token
mp_lexer_next_token_into(lex, &lex->tok_cur, true);
return lex;
}
void mp_lexer_free(mp_lexer_t *lex) {
if (lex) {
if (lex->stream_close) {
lex->stream_close(lex->stream_data);
}
vstr_clear(&lex->vstr);
m_del(uint16_t, lex->indent_level, lex->alloc_indent_level);
m_del_obj(mp_lexer_t, lex);
}
}
qstr mp_lexer_source_name(mp_lexer_t *lex) {
return lex->source_name;
}
void mp_lexer_to_next(mp_lexer_t *lex) {
mp_lexer_next_token_into(lex, &lex->tok_cur, false);
}
const mp_token_t *mp_lexer_cur(const mp_lexer_t *lex) {
return &lex->tok_cur;
}
bool mp_lexer_is_kind(mp_lexer_t *lex, mp_token_kind_t kind) {
return lex->tok_cur.kind == kind;
}
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