mirror of
https://github.com/python/cpython
synced 2024-09-15 21:10:21 +00:00
500 lines
9.6 KiB
C
500 lines
9.6 KiB
C
/* Tokenizer implementation */
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/* XXX This is rather old, should be restructured perhaps */
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/* XXX Need a better interface to report errors than writing to stderr */
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/* XXX Should use editor resource to fetch true tab size on Macintosh */
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#include "pgenheaders.h"
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#include <ctype.h>
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#include "string.h"
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#include "fgetsintr.h"
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#include "tokenizer.h"
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#include "errcode.h"
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#ifdef THINK_C
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#define TABSIZE 4
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#endif
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#ifndef TABSIZE
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#define TABSIZE 8
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#endif
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/* Forward */
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static struct tok_state *tok_new PROTO((void));
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static int tok_nextc PROTO((struct tok_state *tok));
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static void tok_backup PROTO((struct tok_state *tok, int c));
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/* Token names */
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char *tok_name[] = {
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"ENDMARKER",
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"NAME",
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"NUMBER",
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"STRING",
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"NEWLINE",
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"INDENT",
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"DEDENT",
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"LPAR",
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"RPAR",
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"LSQB",
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"RSQB",
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"COLON",
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"COMMA",
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"SEMI",
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"PLUS",
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"MINUS",
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"STAR",
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"SLASH",
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"VBAR",
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"AMPER",
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"LESS",
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"GREATER",
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"EQUAL",
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"DOT",
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"PERCENT",
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"BACKQUOTE",
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"LBRACE",
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"RBRACE",
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"OP",
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"<ERRORTOKEN>",
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"<N_TOKENS>"
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};
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/* Create and initialize a new tok_state structure */
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static struct tok_state *
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tok_new()
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{
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struct tok_state *tok = NEW(struct tok_state, 1);
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if (tok == NULL)
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return NULL;
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tok->buf = tok->cur = tok->end = tok->inp = NULL;
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tok->done = E_OK;
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tok->fp = NULL;
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tok->tabsize = TABSIZE;
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tok->indent = 0;
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tok->indstack[0] = 0;
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tok->atbol = 1;
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tok->pendin = 0;
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tok->prompt = tok->nextprompt = NULL;
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tok->lineno = 0;
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return tok;
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}
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/* Set up tokenizer for string */
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struct tok_state *
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tok_setups(str)
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char *str;
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{
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struct tok_state *tok = tok_new();
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if (tok == NULL)
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return NULL;
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tok->buf = tok->cur = str;
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tok->end = tok->inp = strchr(str, '\0');
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return tok;
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}
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/* Set up tokenizer for string */
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struct tok_state *
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tok_setupf(fp, ps1, ps2)
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FILE *fp;
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char *ps1, *ps2;
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{
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struct tok_state *tok = tok_new();
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if (tok == NULL)
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return NULL;
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if ((tok->buf = NEW(char, BUFSIZ)) == NULL) {
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DEL(tok);
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return NULL;
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}
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tok->cur = tok->inp = tok->buf;
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tok->end = tok->buf + BUFSIZ;
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tok->fp = fp;
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tok->prompt = ps1;
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tok->nextprompt = ps2;
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return tok;
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}
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/* Free a tok_state structure */
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void
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tok_free(tok)
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struct tok_state *tok;
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{
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/* XXX really need a separate flag to say 'my buffer' */
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if (tok->fp != NULL && tok->buf != NULL)
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DEL(tok->buf);
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DEL(tok);
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}
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/* Get next char, updating state; error code goes into tok->done */
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static int
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tok_nextc(tok)
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register struct tok_state *tok;
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{
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if (tok->done != E_OK)
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return EOF;
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for (;;) {
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if (tok->cur < tok->inp)
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return *tok->cur++;
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if (tok->fp == NULL) {
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tok->done = E_EOF;
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return EOF;
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}
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if (tok->inp > tok->buf && tok->inp[-1] == '\n')
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tok->inp = tok->buf;
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if (tok->inp == tok->end) {
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int n = tok->end - tok->buf;
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char *new = tok->buf;
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RESIZE(new, char, n+n);
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if (new == NULL) {
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fprintf(stderr, "tokenizer out of mem\n");
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tok->done = E_NOMEM;
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return EOF;
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}
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tok->buf = new;
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tok->inp = tok->buf + n;
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tok->end = tok->inp + n;
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}
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#ifdef USE_READLINE
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if (tok->prompt != NULL) {
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extern char *readline PROTO((char *prompt));
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static int been_here;
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if (!been_here) {
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/* Force rebind of TAB to insert-tab */
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extern int rl_insert();
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rl_bind_key('\t', rl_insert);
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been_here++;
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}
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if (tok->buf != NULL)
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free(tok->buf);
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tok->buf = readline(tok->prompt);
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(void) intrcheck(); /* Clear pending interrupt */
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if (tok->nextprompt != NULL)
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tok->prompt = tok->nextprompt;
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/* XXX different semantics w/o readline()! */
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if (tok->buf == NULL) {
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tok->done = E_EOF;
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}
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else {
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unsigned int n = strlen(tok->buf);
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if (n > 0)
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add_history(tok->buf);
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/* Append the '\n' that readline()
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doesn't give us, for the tokenizer... */
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tok->buf = realloc(tok->buf, n+2);
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if (tok->buf == NULL)
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tok->done = E_NOMEM;
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else {
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tok->end = tok->buf + n;
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*tok->end++ = '\n';
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*tok->end = '\0';
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tok->inp = tok->end;
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tok->cur = tok->buf;
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}
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}
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}
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else
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#endif
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{
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tok->cur = tok->inp;
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if (tok->prompt != NULL && tok->inp == tok->buf) {
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fprintf(stderr, "%s", tok->prompt);
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tok->prompt = tok->nextprompt;
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}
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tok->done = fgets_intr(tok->inp,
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(int)(tok->end - tok->inp), tok->fp);
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}
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if (tok->done != E_OK) {
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if (tok->prompt != NULL)
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fprintf(stderr, "\n");
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return EOF;
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}
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tok->inp = strchr(tok->inp, '\0');
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}
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}
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/* Back-up one character */
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static void
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tok_backup(tok, c)
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register struct tok_state *tok;
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register int c;
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{
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if (c != EOF) {
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if (--tok->cur < tok->buf) {
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fprintf(stderr, "tok_backup: begin of buffer\n");
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abort();
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}
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if (*tok->cur != c)
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*tok->cur = c;
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}
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}
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/* Return the token corresponding to a single character */
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int
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tok_1char(c)
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int c;
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{
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switch (c) {
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case '(': return LPAR;
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case ')': return RPAR;
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case '[': return LSQB;
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case ']': return RSQB;
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case ':': return COLON;
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case ',': return COMMA;
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case ';': return SEMI;
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case '+': return PLUS;
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case '-': return MINUS;
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case '*': return STAR;
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case '/': return SLASH;
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case '|': return VBAR;
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case '&': return AMPER;
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case '<': return LESS;
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case '>': return GREATER;
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case '=': return EQUAL;
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case '.': return DOT;
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case '%': return PERCENT;
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case '`': return BACKQUOTE;
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case '{': return LBRACE;
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case '}': return RBRACE;
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default: return OP;
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}
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}
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/* Get next token, after space stripping etc. */
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int
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tok_get(tok, p_start, p_end)
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register struct tok_state *tok; /* In/out: tokenizer state */
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char **p_start, **p_end; /* Out: point to start/end of token */
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{
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register int c;
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/* Get indentation level */
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if (tok->atbol) {
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register int col = 0;
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tok->atbol = 0;
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tok->lineno++;
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for (;;) {
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c = tok_nextc(tok);
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if (c == ' ')
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col++;
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else if (c == '\t')
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col = (col/tok->tabsize + 1) * tok->tabsize;
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else
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break;
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}
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tok_backup(tok, c);
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if (col == tok->indstack[tok->indent]) {
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/* No change */
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}
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else if (col > tok->indstack[tok->indent]) {
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/* Indent -- always one */
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if (tok->indent+1 >= MAXINDENT) {
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fprintf(stderr, "excessive indent\n");
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tok->done = E_TOKEN;
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return ERRORTOKEN;
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}
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tok->pendin++;
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tok->indstack[++tok->indent] = col;
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}
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else /* col < tok->indstack[tok->indent] */ {
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/* Dedent -- any number, must be consistent */
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while (tok->indent > 0 &&
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col < tok->indstack[tok->indent]) {
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tok->indent--;
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tok->pendin--;
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}
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if (col != tok->indstack[tok->indent]) {
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fprintf(stderr, "inconsistent dedent\n");
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tok->done = E_TOKEN;
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return ERRORTOKEN;
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}
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}
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}
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*p_start = *p_end = tok->cur;
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/* Return pending indents/dedents */
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if (tok->pendin != 0) {
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if (tok->pendin < 0) {
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tok->pendin++;
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return DEDENT;
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}
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else {
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tok->pendin--;
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return INDENT;
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}
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}
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again:
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/* Skip spaces */
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do {
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c = tok_nextc(tok);
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} while (c == ' ' || c == '\t');
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/* Set start of current token */
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*p_start = tok->cur - 1;
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/* Skip comment */
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if (c == '#') {
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/* Hack to allow overriding the tabsize in the file.
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This is also recognized by vi, when it occurs near the
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beginning or end of the file. (Will vi never die...?) */
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int x;
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/* XXX The case to (unsigned char *) is needed by THINK C 3.0 */
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if (sscanf(/*(unsigned char *)*/tok->cur,
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" vi:set tabsize=%d:", &x) == 1 &&
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x >= 1 && x <= 40) {
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fprintf(stderr, "# vi:set tabsize=%d:\n", x);
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tok->tabsize = x;
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}
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do {
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c = tok_nextc(tok);
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} while (c != EOF && c != '\n');
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}
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/* Check for EOF and errors now */
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if (c == EOF)
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return tok->done == E_EOF ? ENDMARKER : ERRORTOKEN;
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/* Identifier (most frequent token!) */
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if (isalpha(c) || c == '_') {
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do {
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c = tok_nextc(tok);
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} while (isalnum(c) || c == '_');
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tok_backup(tok, c);
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*p_end = tok->cur;
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return NAME;
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}
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/* Newline */
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if (c == '\n') {
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tok->atbol = 1;
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*p_end = tok->cur - 1; /* Leave '\n' out of the string */
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return NEWLINE;
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}
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/* Number */
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if (isdigit(c)) {
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if (c == '0') {
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/* Hex or octal */
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c = tok_nextc(tok);
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if (c == '.')
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goto fraction;
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if (c == 'x' || c == 'X') {
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/* Hex */
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do {
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c = tok_nextc(tok);
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} while (isxdigit(c));
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}
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else {
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/* Octal; c is first char of it */
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/* There's no 'isoctdigit' macro, sigh */
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while ('0' <= c && c < '8') {
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c = tok_nextc(tok);
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}
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}
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}
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else {
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/* Decimal */
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do {
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c = tok_nextc(tok);
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} while (isdigit(c));
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/* Accept floating point numbers.
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XXX This accepts incomplete things like 12e or 1e+;
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worry about that at run-time.
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XXX Doesn't accept numbers starting with a dot */
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if (c == '.') {
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fraction:
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/* Fraction */
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do {
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c = tok_nextc(tok);
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} while (isdigit(c));
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}
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if (c == 'e' || c == 'E') {
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/* Exponent part */
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c = tok_nextc(tok);
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if (c == '+' || c == '-')
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c = tok_nextc(tok);
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while (isdigit(c)) {
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c = tok_nextc(tok);
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}
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}
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}
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tok_backup(tok, c);
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*p_end = tok->cur;
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return NUMBER;
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}
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/* String */
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if (c == '\'') {
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for (;;) {
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c = tok_nextc(tok);
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if (c == '\n' || c == EOF) {
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tok->done = E_TOKEN;
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return ERRORTOKEN;
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}
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if (c == '\\') {
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c = tok_nextc(tok);
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*p_end = tok->cur;
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if (c == '\n' || c == EOF) {
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tok->done = E_TOKEN;
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return ERRORTOKEN;
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}
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continue;
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}
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if (c == '\'')
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break;
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}
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*p_end = tok->cur;
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return STRING;
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}
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/* Line continuation */
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if (c == '\\') {
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c = tok_nextc(tok);
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if (c != '\n') {
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tok->done = E_TOKEN;
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return ERRORTOKEN;
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}
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tok->lineno++;
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goto again; /* Read next line */
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}
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/* Punctuation character */
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*p_end = tok->cur;
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return tok_1char(c);
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}
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#ifdef DEBUG
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void
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tok_dump(type, start, end)
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int type;
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char *start, *end;
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{
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printf("%s", tok_name[type]);
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if (type == NAME || type == NUMBER || type == STRING || type == OP)
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printf("(%.*s)", (int)(end - start), start);
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}
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#endif
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