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review.linaro.org / lite / micropython / 27fb45eb1c95f9cc02f4ed1b9d573ece0d4c1a18 / . / py / lexer.c
blob: 56f1ed0df406a411de29806dcd4f279e6f57022e [file] [log] [blame]
/* lexer.c -- simple tokeniser for Python implementation
*/
#include <stdint.h>
#include <stdio.h>
#include <assert.h>
#include "misc.h"
#include "lexer.h"
#define TAB_SIZE (8)
struct _py_lexer_t {
const char *name; // name of source
void *stream_data; // data for stream
py_lexer_stream_next_char_t stream_next_char; // stream callback to get next char
py_lexer_stream_free_t stream_free; // 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;
py_token_t tok_cur;
};
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;
}
void py_token_show(const py_token_t *tok) {
printf("(%s:%d:%d) kind:%d str:%p len:%d", tok->src_name, 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 = g_utf8_get_char(i);
i = g_utf8_next_char(i);
if (g_unichar_isprint(c)) {
printf("%c", c);
} else {
printf("?");
}
}
}
printf("\n");
}
void py_token_show_error_prefix(const py_token_t *tok) {
printf("(%s:%d:%d) ", tok->src_name, tok->src_line, tok->src_column);
}
bool py_token_show_error(const py_token_t *tok, const char *msg) {
printf("(%s:%d:%d) %s\n", tok->src_name, tok->src_line, tok->src_column, msg);
return false;
}
#define CUR_CHAR(lex) ((lex)->chr0)
static bool is_end(py_lexer_t *lex) {
return lex->chr0 == PY_LEXER_CHAR_EOF;
}
static bool is_physical_newline(py_lexer_t *lex) {
return lex->chr0 == '\n' || lex->chr0 == '\r';
}
static bool is_char(py_lexer_t *lex, char c) {
return lex->chr0 == c;
}
static bool is_char_or(py_lexer_t *lex, char c1, char c2) {
return lex->chr0 == c1 || lex->chr0 == c2;
}
static bool is_char_or3(py_lexer_t *lex, char c1, char c2, char c3) {
return lex->chr0 == c1 || lex->chr0 == c2 || lex->chr0 == c3;
}
/*
static bool is_char_following(py_lexer_t *lex, char c) {
return lex->chr1 == c;
}
*/
static bool is_char_following_or(py_lexer_t *lex, char c1, char c2) {
return lex->chr1 == c1 || lex->chr1 == c2;
}
static bool is_char_following_following_or(py_lexer_t *lex, char c1, char c2) {
return lex->chr2 == c1 || lex->chr2 == c2;
}
static bool is_char_and(py_lexer_t *lex, char c1, char c2) {
return lex->chr0 == c1 && lex->chr1 == c2;
}
static bool is_whitespace(py_lexer_t *lex) {
return g_unichar_isspace(lex->chr0);
}
static bool is_letter(py_lexer_t *lex) {
return g_unichar_isalpha(lex->chr0);
}
static bool is_digit(py_lexer_t *lex) {
return g_unichar_isdigit(lex->chr0);
}
static bool is_following_digit(py_lexer_t *lex) {
return g_unichar_isdigit(lex->chr1);
}
// TODO UNICODE include unicode characters in definition of identifiers
static bool is_head_of_identifier(py_lexer_t *lex) {
return is_letter(lex) || lex->chr0 == '_';
}
// TODO UNICODE include unicode characters in definition of identifiers
static bool is_tail_of_identifier(py_lexer_t *lex) {
return is_head_of_identifier(lex) || is_digit(lex);
}
static void next_char(py_lexer_t *lex) {
if (lex->chr0 == PY_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 == PY_LEXER_CHAR_EOF) {
// EOF
if (lex->chr1 != PY_LEXER_CHAR_EOF && lex->chr1 != '\n' && lex->chr1 != '\r') {
lex->chr2 = '\n'; // insert newline at end of file
}
}
}
}
void indent_push(py_lexer_t *lex, uint indent) {
if (lex->num_indent_level >= lex->alloc_indent_level) {
lex->alloc_indent_level *= 2;
lex->indent_level = m_renew(uint16_t, lex->indent_level, lex->alloc_indent_level);
}
lex->indent_level[lex->num_indent_level++] = indent;
}
uint indent_top(py_lexer_t *lex) {
return lex->indent_level[lex->num_indent_level - 1];
}
void indent_pop(py_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=" // !=
".c.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[] = {
PY_TOKEN_DEL_PAREN_OPEN, PY_TOKEN_DEL_PAREN_CLOSE,
PY_TOKEN_DEL_BRACKET_OPEN, PY_TOKEN_DEL_BRACKET_CLOSE,
PY_TOKEN_DEL_BRACE_OPEN, PY_TOKEN_DEL_BRACE_CLOSE,
PY_TOKEN_DEL_COMMA, PY_TOKEN_DEL_COLON, PY_TOKEN_DEL_SEMICOLON, PY_TOKEN_DEL_AT, PY_TOKEN_OP_TILDE,
PY_TOKEN_OP_LESS, PY_TOKEN_OP_LESS_EQUAL, PY_TOKEN_OP_DBL_LESS, PY_TOKEN_DEL_DBL_LESS_EQUAL,
PY_TOKEN_OP_MORE, PY_TOKEN_OP_MORE_EQUAL, PY_TOKEN_OP_DBL_MORE, PY_TOKEN_DEL_DBL_MORE_EQUAL,
PY_TOKEN_OP_STAR, PY_TOKEN_DEL_STAR_EQUAL, PY_TOKEN_OP_DBL_STAR, PY_TOKEN_DEL_DBL_STAR_EQUAL,
PY_TOKEN_OP_PLUS, PY_TOKEN_DEL_PLUS_EQUAL,
PY_TOKEN_OP_MINUS, PY_TOKEN_DEL_MINUS_EQUAL, PY_TOKEN_DEL_MINUS_MORE,
PY_TOKEN_OP_AMPERSAND, PY_TOKEN_DEL_AMPERSAND_EQUAL,
PY_TOKEN_OP_PIPE, PY_TOKEN_DEL_PIPE_EQUAL,
PY_TOKEN_OP_SLASH, PY_TOKEN_DEL_SLASH_EQUAL, PY_TOKEN_OP_DBL_SLASH, PY_TOKEN_DEL_DBL_SLASH_EQUAL,
PY_TOKEN_OP_PERCENT, PY_TOKEN_DEL_PERCENT_EQUAL,
PY_TOKEN_OP_CARET, PY_TOKEN_DEL_CARET_EQUAL,
PY_TOKEN_DEL_EQUAL, PY_TOKEN_OP_DBL_EQUAL,
PY_TOKEN_OP_NOT_EQUAL,
PY_TOKEN_DEL_PERIOD, PY_TOKEN_ELLIPSES,
};
// 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 void py_lexer_next_token_into(py_lexer_t *lex, py_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)) {
// TODO SyntaxError
assert(0);
} else {
next_char(lex);
}
} else {
break;
}
}
// set token source information
tok->src_name = lex->name;
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 = PY_TOKEN_INDENT;
} else if (lex->emit_dent < 0) {
tok->kind = PY_TOKEN_DEDENT;
lex->emit_dent += 1;
} else if (lex->emit_dent > 0) {
tok->kind = PY_TOKEN_INDENT;
lex->emit_dent -= 1;
} else if (had_physical_newline && lex->nested_bracket_level == 0) {
tok->kind = PY_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 = PY_TOKEN_DEDENT_MISMATCH;
}
}
} else if (is_end(lex)) {
if (indent_top(lex) > 0) {
tok->kind = PY_TOKEN_NEWLINE;
lex->emit_dent = 0;
while (indent_top(lex) > 0) {
indent_pop(lex);
lex->emit_dent -= 1;
}
} else {
tok->kind = PY_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 = PY_TOKEN_BYTES;
} else {
tok->kind = PY_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_raw && is_char(lex, '\\')) {
next_char(lex);
unichar c = CUR_CHAR(lex);
switch (c) {
case PY_LEXER_CHAR_EOF: break; // TODO a proper error message?
case '\n': c = PY_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;
// TODO \ooo octal
case 'x': // TODO \xhh
case 'N': // TODO \N{name} only in strings
case 'u': // TODO \uxxxx only in strings
case 'U': // TODO \Uxxxxxxxx only in strings
default: break; // TODO error message
}
if (c != PY_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 = PY_TOKEN_LONELY_STRING_OPEN;
}
// cut off the end quotes from the token text
vstr_cut_tail(&lex->vstr, n_closing);
} else if (is_head_of_identifier(lex)) {
tok->kind = PY_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 = PY_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 {
// 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 = PY_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 = PY_TOKEN_INVALID;
}
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];
// compute bracket level for implicit line joining
if (tok->kind == PY_TOKEN_DEL_PAREN_OPEN || tok->kind == PY_TOKEN_DEL_BRACKET_OPEN || tok->kind == PY_TOKEN_DEL_BRACE_OPEN) {
lex->nested_bracket_level += 1;
} else if (tok->kind == PY_TOKEN_DEL_PAREN_CLOSE || tok->kind == PY_TOKEN_DEL_BRACKET_CLOSE || tok->kind == PY_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 == PY_TOKEN_NAME) {
for (int i = 0; tok_kw[i] != NULL; i++) {
if (str_strn_equal(tok_kw[i], tok->str, tok->len)) {
tok->kind = PY_TOKEN_KW_FALSE + i;
break;
}
}
}
}
py_lexer_t *py_lexer_new(const char *src_name, void *stream_data, py_lexer_stream_next_char_t stream_next_char, py_lexer_stream_free_t stream_free) {
py_lexer_t *lex = m_new(py_lexer_t, 1);
lex->name = src_name; // TODO do we need to strdup this?
lex->stream_data = stream_data;
lex->stream_next_char = stream_next_char;
lex->stream_free = stream_free;
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);
// 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 == PY_LEXER_CHAR_EOF) {
lex->chr0 = '\n';
} else if (lex->chr1 == PY_LEXER_CHAR_EOF) {
if (lex->chr0 != '\n' && lex->chr0 != '\r') {
lex->chr1 = '\n';
}
} else if (lex->chr2 == PY_LEXER_CHAR_EOF) {
if (lex->chr1 != '\n' && lex->chr1 != '\r') {
lex->chr2 = '\n';
}
}
// preload first token
py_lexer_next_token_into(lex, &lex->tok_cur, true);
return lex;
}
void py_lexer_free(py_lexer_t *lex) {
if (lex) {
if (lex->stream_free) {
lex->stream_free(lex->stream_data);
}
m_free(lex);
}
}
void py_lexer_to_next(py_lexer_t *lex) {
py_lexer_next_token_into(lex, &lex->tok_cur, false);
}
const py_token_t *py_lexer_cur(const py_lexer_t *lex) {
return &lex->tok_cur;
}
bool py_lexer_is_kind(py_lexer_t *lex, py_token_kind_t kind) {
return lex->tok_cur.kind == kind;
}
/*
bool py_lexer_is_str(py_lexer_t *lex, const char *str) {
return py_token_is_str(&lex->tok_cur, str);
}
bool py_lexer_opt_kind(py_lexer_t *lex, py_token_kind_t kind) {
if (py_lexer_is_kind(lex, kind)) {
py_lexer_to_next(lex);
return true;
}
return false;
}
bool py_lexer_opt_str(py_lexer_t *lex, const char *str) {
if (py_lexer_is_str(lex, str)) {
py_lexer_to_next(lex);
return true;
}
return false;
}
*/
bool py_lexer_show_error(py_lexer_t *lex, const char *msg) {
return py_token_show_error(&lex->tok_cur, msg);
}
bool py_lexer_show_error_pythonic(py_lexer_t *lex, const char *msg) {
printf(" File \"%s\", line %d column %d\n%s\n", lex->tok_cur.src_name, lex->tok_cur.src_line, lex->tok_cur.src_column, msg);
return false;
}