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lexer.c
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lexer.c
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#include <stdlib.h>
#include "lexer.h"
#include "buffer.h"
#include "utils.h"
void print_state(const char *state_name, int c)
{
fprintf(stderr, "Lexer: %s; ", state_name);
switch (c) {
case '\n':
fprintf(stderr, "\'\\n\';\n");
break;
case EOF:
fprintf(stderr, "\'EOF\';\n");
break;
default:
fprintf(stderr, "\'%c\';\n", c);
break;
}
}
void print_lex(FILE *stream, lexeme *lex)
{
fprintf(stream, "!!! Lexeme: ");
switch (lex->type) {
case LEX_INPUT: /* '<' */
fprintf(stream, "[<]\n");
break;
case LEX_OUTPUT: /* '>' */
fprintf(stream, "[>]\n");
break;
case LEX_APPEND: /* '>>' */
fprintf(stream, "[>>]\n");
break;
case LEX_PIPE: /* '|' */
fprintf(stream, "[|]\n");
break;
case LEX_OR: /* '||' */
fprintf(stream, "[||]\n");
break;
case LEX_BACKGROUND: /* '&' */
fprintf(stream, "[&]\n");
break;
case LEX_AND: /* '&&' */
fprintf(stream, "[&&]\n");
break;
case LEX_SEMICOLON: /* ';' */
fprintf(stream, "[;]\n");
break;
case LEX_BRACKET_OPEN: /* '(' */
fprintf(stream, "[(]\n");
break;
case LEX_BRACKET_CLOSE: /* ')' */
fprintf(stream, "[)]\n");
break;
case LEX_REVERSE: /* '`' */
fprintf(stream, "[`]\n");
break;
case LEX_WORD: /* all different */
fprintf(stream, "[WORD:%s]\n", lex->str);
break;
case LEX_EOLINE: /* '\n' */
fprintf(stream, "[EOLINE]\n");
break;
case LEX_EOFILE: /* EOF */
fprintf(stream, "[EOFILE]\n");
break;
case LEX_ERROR: /* error in lexer */
fprintf(stream, "[ERROR]\n");
break;
}
}
void deferred_get_char(lexer_info *linfo)
{
linfo->get_next_char = 1;
}
void get_char(lexer_info *linfo)
{
linfo->c = getchar();
}
void init_lexer(lexer_info *linfo)
{
/* lexer_info *linfo =
(lexer_info *) malloc(sizeof(lexer_info)); */
deferred_get_char(linfo);
linfo->state = ST_START;
}
lexeme *make_lex(type_of_lex type)
{
lexeme *lex = (lexeme *) malloc(sizeof(lexeme));
/* lex->next = NULL; */
lex->type = type;
lex->str = NULL;
return lex;
}
void destroy_lex(lexeme *lex)
{
if (lex->str != NULL)
free(lex->str);
free(lex);
}
lexeme *st_start(lexer_info *linfo, buffer *buf)
{
#ifdef LEXER_DEBUG
print_state("ST_START", linfo->c);
#endif
switch (linfo->c) {
case EOF:
case '\n':
linfo->state = ST_EOLN_EOF;
break;
case ' ':
case '\t':
deferred_get_char(linfo);
break;
case '<':
case ';':
case '(':
case ')':
case '`':
linfo->state = ST_ONE_SYM_LEX;
break;
case '>':
case '|':
case '&':
linfo->state = ST_ONE_TWO_SYM_LEX;
break;
case '\\':
case '\"':
default:
linfo->state = ST_WORD;
break;
}
return NULL;
}
lexeme *st_one_sym_lex(lexer_info *linfo, buffer *buf)
{
lexeme *lex = NULL;
#ifdef LEXER_DEBUG
print_state("ST_ONE_SYM_LEX", linfo->c);
#endif
switch (linfo->c) {
case '<':
lex = make_lex(LEX_INPUT);
break;
case ';':
lex = make_lex(LEX_SEMICOLON);
break;
case '(':
lex = make_lex(LEX_BRACKET_OPEN);
break;
case ')':
lex = make_lex(LEX_BRACKET_CLOSE);
break;
case '`':
lex = make_lex(LEX_REVERSE);
break;
default:
fprintf(stderr, "Lexer: error in ST_ONE_SYM_LEX;");
print_state("ST_ONE_SYM_LEX", linfo->c);
exit(ES_LEXER_INCURABLE_ERROR);
}
/* We don't need buffer */
deferred_get_char(linfo);
linfo->state = ST_START;
return lex;
}
lexeme *st_one_two_sym_lex(lexer_info *linfo, buffer *buf)
{
lexeme *lex = NULL;
#ifdef LEXER_DEBUG
print_state("ST_ONE_TWO_SYM_LEX", linfo->c);
#endif
if (buf->count_sym == 0) {
add_to_buffer(buf, linfo->c);
deferred_get_char(linfo);
} else if (buf->count_sym == 1) {
/* TODO: make it more pretty */
char prev_c = get_last_from_buffer(buf);
clear_buffer(buf);
switch (prev_c) {
case '>':
lex = (prev_c == linfo->c) ?
make_lex(LEX_APPEND) :
make_lex(LEX_OUTPUT);
break;
case '|':
lex = (prev_c == linfo->c) ?
make_lex(LEX_OR) :
make_lex(LEX_PIPE);
break;
case '&':
lex = (prev_c == linfo->c) ?
make_lex(LEX_AND) :
make_lex(LEX_BACKGROUND);
break;
default:
fprintf(stderr, "Lexer: error (type 1) in ST_ONE_TWO_SYM_LEX;");
print_state("ST_ONE_TWO_SYM_LEX", linfo->c);
exit(ES_LEXER_INCURABLE_ERROR);
}
if (prev_c == linfo->c)
deferred_get_char(linfo);
linfo->state = ST_START;
return lex;
} else {
fprintf(stderr, "Lexer: error (type 2) in ST_ONE_TWO_SYM_LEX;");
print_state("ST_ONE_TWO_SYM_LEX", linfo->c);
exit(ES_LEXER_INCURABLE_ERROR);
}
return lex;
}
lexeme *st_backslash(lexer_info *linfo, buffer *buf)
{
#ifdef LEXER_DEBUG
print_state("ST_BACKSLASH", linfo->c);
#endif
switch (linfo->c) {
case EOF:
linfo->state = ST_ERROR;
return NULL;
case '\n':
/* Ignore newline symbol */
print_prompt2();
break;
/* Non bash-like behaviour. In bash substitution
* makes in $'string' costruction. */
case 'a':
add_to_buffer(buf, '\a');
break;
case 'b':
add_to_buffer(buf, '\b');
break;
case 'f':
add_to_buffer(buf, '\f');
break;
case 'n':
add_to_buffer(buf, '\n');
break;
case 'r':
add_to_buffer(buf, '\r');
break;
case 't':
add_to_buffer(buf, '\t');
break;
case 'v':
add_to_buffer(buf, '\v');
break;
default:
add_to_buffer(buf, linfo->c);
break;
}
deferred_get_char(linfo);
linfo->state = ST_WORD;
return NULL;
}
lexeme *st_backslash_in_quotes(lexer_info *linfo, buffer *buf)
{
#ifdef LEXER_DEBUG
print_state("ST_BACKSLASH_IN_QUOTES", linfo->c);
#endif
switch (linfo->c) {
case EOF:
linfo->state = ST_ERROR;
break;
case '\"':
add_to_buffer(buf, linfo->c);
break;
case '\n':
print_prompt2();
/* fallthrough */
default:
add_to_buffer(buf, '\\');
add_to_buffer(buf, linfo->c);
break;
}
deferred_get_char(linfo);
linfo->state = ST_IN_QUOTES;
return NULL;
}
lexeme *st_in_quotes(lexer_info *linfo, buffer *buf)
{
#ifdef LEXER_DEBUG
print_state("ST_IN_QUOTES", linfo->c);
#endif
switch (linfo->c) {
case EOF:
linfo->state = ST_ERROR;
return NULL;
case '\\':
deferred_get_char(linfo);
linfo->state = ST_BACKSLASH_IN_QUOTES;
break;
case '\"':
deferred_get_char(linfo);
linfo->state = ST_WORD;
break;
case '\n':
print_prompt2();
/* fallthrough */
default:
add_to_buffer(buf, linfo->c);
deferred_get_char(linfo);
break;
}
return NULL;
}
lexeme *st_word(lexer_info *linfo, buffer *buf)
{
lexeme *lex = NULL;
#ifdef LEXER_DEBUG
print_state("ST_WORD", linfo->c);
#endif
switch (linfo->c) {
case EOF:
case '\n':
case ' ':
case '\t':
case '<':
case ';':
case '(':
case ')':
case '>':
case '|':
case '&':
case '`':
linfo->state = ST_START;
lex = make_lex(LEX_WORD);
lex->str = convert_to_string(buf, 1);
return lex;
case '\\':
deferred_get_char(linfo);
linfo->state = ST_BACKSLASH;
break;
case '\"':
deferred_get_char(linfo);
linfo->state = ST_IN_QUOTES;
break;
default:
add_to_buffer(buf, linfo->c);
deferred_get_char(linfo);
}
return lex;
}
lexeme *st_error(lexer_info *linfo, buffer *buf)
{
lexeme *lex = NULL;
lex = make_lex(LEX_ERROR);
print_state("ST_ERROR", linfo->c);
clear_buffer(buf);
linfo->get_next_char = 0;
linfo->state = ST_START;
/* TODO: read to '\n' or EOF (flush read buffer) */
return lex;
}
lexeme *st_eoln_eof(lexer_info *linfo, buffer *buf)
{
lexeme *lex = NULL;
#ifdef LEXER_DEBUG
print_state("ST_EOLN_EOF", linfo->c);
#endif
switch (linfo->c) {
case '\n':
lex = make_lex(LEX_EOLINE);
break;
case EOF:
lex = make_lex(LEX_EOFILE);
break;
default:
fprintf(stderr, "Lexer: error in ST_EOLN_EOF;");
print_state("ST_EOLN_EOF", linfo->c);
exit(ES_LEXER_INCURABLE_ERROR);
}
deferred_get_char(linfo);
linfo->state = ST_START;
return lex;
}
lexeme *get_lex(lexer_info *linfo)
{
lexeme *lex = NULL;
buffer buf;
new_buffer(&buf);
do {
if (linfo->get_next_char) {
linfo->get_next_char = 0;
get_char(linfo);
}
switch (linfo->state) {
case ST_START:
lex = st_start(linfo, &buf);
break;
case ST_ONE_SYM_LEX:
lex = st_one_sym_lex(linfo, &buf);
break;
case ST_ONE_TWO_SYM_LEX:
lex = st_one_two_sym_lex(linfo, &buf);
break;
case ST_BACKSLASH:
lex = st_backslash(linfo, &buf);
break;
case ST_BACKSLASH_IN_QUOTES:
lex = st_backslash_in_quotes(linfo, &buf);
break;
case ST_IN_QUOTES:
lex = st_in_quotes(linfo, &buf);
break;
case ST_WORD:
lex = st_word(linfo, &buf);
break;
case ST_ERROR:
lex = st_error(linfo, &buf);
break;
case ST_EOLN_EOF:
lex = st_eoln_eof(linfo, &buf);
break;
} /* switch */
} while (lex == NULL);
return lex;
}
/*
gcc -g -Wall -ansi -pedantic -c buffer.c -o buffer.o &&
gcc -g -Wall -ansi -pedantic -c utils.c -o utils.o &&
gcc -g -Wall -ansi -pedantic lexer.c buffer.o utils.o -o lexer
*/
#if 0
int main()
{
lexer_info linfo;
init_lexer(&linfo);
do {
lexeme *lex = get_lex(&linfo);
print_lex(stdout, lex);
if (lex->type == LEX_EOFILE)
return 0;
destroy_lex(lex);
if (linfo.state == ST_ERROR) {
fprintf(stderr, "(>_<)\n");
continue;
}
} while (1);
}
#endif