+DEFUN ("forward-comment", Fforward_comment, Sforward_comment, 1, 1, 0,
+ "Move forward across up to N comments. If N is negative, move backward.\n\
+Stop scanning if we find something other than a comment or whitespace.\n\
+Set point to where scanning stops.\n\
+If N comments are found as expected, with nothing except whitespace\n\
+between them, return t; otherwise return nil.")
+ (count)
+ Lisp_Object count;
+{
+ register int from;
+ register int stop;
+ register int c;
+ register enum syntaxcode code;
+ int comstyle = 0; /* style of comment encountered */
+ int found;
+ int count1;
+
+ CHECK_NUMBER (count, 0);
+ count1 = XINT (count);
+
+ immediate_quit = 1;
+ QUIT;
+
+ from = PT;
+
+ while (count1 > 0)
+ {
+ stop = ZV;
+ do
+ {
+ if (from == stop)
+ {
+ SET_PT (from);
+ immediate_quit = 0;
+ return Qnil;
+ }
+ c = FETCH_CHAR (from);
+ code = SYNTAX (c);
+ from++;
+ comstyle = 0;
+ if (from < stop && SYNTAX_COMSTART_FIRST (c)
+ && SYNTAX_COMSTART_SECOND (FETCH_CHAR (from)))
+ {
+ /* We have encountered a comment start sequence and we
+ are ignoring all text inside comments. We must record
+ the comment style this sequence begins so that later,
+ only a comment end of the same style actually ends
+ the comment section. */
+ code = Scomment;
+ comstyle = SYNTAX_COMMENT_STYLE (FETCH_CHAR (from));
+ from++;
+ }
+ }
+ while (code == Swhitespace || code == Sendcomment);
+ if (code != Scomment)
+ {
+ immediate_quit = 0;
+ SET_PT (from - 1);
+ return Qnil;
+ }
+ /* We're at the start of a comment. */
+ while (1)
+ {
+ if (from == stop)
+ {
+ immediate_quit = 0;
+ SET_PT (from);
+ return Qnil;
+ }
+ c = FETCH_CHAR (from);
+ from++;
+ if (SYNTAX (c) == Sendcomment
+ && SYNTAX_COMMENT_STYLE (c) == comstyle)
+ /* we have encountered a comment end of the same style
+ as the comment sequence which began this comment
+ section */
+ break;
+ if (from < stop && SYNTAX_COMEND_FIRST (c)
+ && SYNTAX_COMEND_SECOND (FETCH_CHAR (from))
+ && SYNTAX_COMMENT_STYLE (c) == comstyle)
+ /* we have encountered a comment end of the same style
+ as the comment sequence which began this comment
+ section */
+ { from++; break; }
+ }
+ /* We have skipped one comment. */
+ count1--;
+ }
+
+ while (count1 < 0)
+ {
+ stop = BEGV;
+ while (from > stop)
+ {
+ int quoted;
+
+ from--;
+ quoted = char_quoted (from);
+ if (quoted)
+ from--;
+ c = FETCH_CHAR (from);
+ code = SYNTAX (c);
+ comstyle = 0;
+ if (code == Sendcomment)
+ comstyle = SYNTAX_COMMENT_STYLE (c);
+ if (from > stop && SYNTAX_COMEND_SECOND (c)
+ && SYNTAX_COMEND_FIRST (FETCH_CHAR (from - 1))
+ && !char_quoted (from - 1))
+ {
+ /* We must record the comment style encountered so that
+ later, we can match only the proper comment begin
+ sequence of the same style. */
+ code = Sendcomment;
+ comstyle = SYNTAX_COMMENT_STYLE (FETCH_CHAR (from - 1));
+ from--;
+ }
+
+ if (code == Sendcomment && !quoted)
+ {
+#if 0
+ if (code != SYNTAX (c))
+ /* For a two-char comment ender, we can assume
+ it does end a comment. So scan back in a simple way. */
+ {
+ if (from != stop) from--;
+ while (1)
+ {
+ if (SYNTAX (c = FETCH_CHAR (from)) == Scomment
+ && SYNTAX_COMMENT_STYLE (c) == comstyle)
+ break;
+ if (from == stop)
+ {
+ immediate_quit = 0;
+ SET_PT (from);
+ return Qnil;
+ }
+ from--;
+ if (SYNTAX_COMSTART_SECOND (c)
+ && SYNTAX_COMSTART_FIRST (FETCH_CHAR (from))
+ && SYNTAX_COMMENT_STYLE (c) == comstyle
+ && !char_quoted (from))
+ break;
+ }
+ break;
+ }
+#endif /* 0 */
+
+ /* Look back, counting the parity of string-quotes,
+ and recording the comment-starters seen.
+ When we reach a safe place, assume that's not in a string;
+ then step the main scan to the earliest comment-starter seen
+ an even number of string quotes away from the safe place.
+
+ OFROM[I] is position of the earliest comment-starter seen
+ which is I+2X quotes from the comment-end.
+ PARITY is current parity of quotes from the comment end. */
+ {
+ int parity = 0;
+ char my_stringend = 0;
+ int string_lossage = 0;
+ int comment_end = from;
+ int comstart_pos = 0;
+ int comstart_parity = 0;
+ int scanstart = from - 1;
+
+ /* At beginning of range to scan, we're outside of strings;
+ that determines quote parity to the comment-end. */
+ while (from != stop)
+ {
+ /* Move back and examine a character. */
+ from--;
+
+ c = FETCH_CHAR (from);
+ code = SYNTAX (c);
+
+ /* If this char is the second of a 2-char comment sequence,
+ back up and give the pair the appropriate syntax. */
+ if (from > stop && SYNTAX_COMEND_SECOND (c)
+ && SYNTAX_COMEND_FIRST (FETCH_CHAR (from - 1)))
+ {
+ code = Sendcomment;
+ from--;
+ c = FETCH_CHAR (from);
+ }
+
+ /* If this char starts a 2-char comment start sequence,
+ treat it like a 1-char comment starter. */
+ if (from < scanstart && SYNTAX_COMSTART_FIRST (c)
+ && SYNTAX_COMSTART_SECOND (FETCH_CHAR (from + 1))
+ && comstyle == SYNTAX_COMMENT_STYLE (FETCH_CHAR (from + 1)))
+ code = Scomment;
+
+ /* Ignore escaped characters. */
+ if (char_quoted (from))
+ continue;
+
+ /* Track parity of quotes. */
+ if (code == Sstring)
+ {
+ parity ^= 1;
+ if (my_stringend == 0)
+ my_stringend = c;
+ /* If we have two kinds of string delimiters.
+ There's no way to grok this scanning backwards. */
+ else if (my_stringend != c)
+ string_lossage = 1;
+ }
+
+ /* Record comment-starters according to that
+ quote-parity to the comment-end. */
+ if (code == Scomment)
+ {
+ comstart_parity = parity;
+ comstart_pos = from;
+ }
+
+ /* If we find another earlier comment-ender,
+ any comment-starts earlier than that don't count
+ (because they go with the earlier comment-ender). */
+ if (code == Sendcomment
+ && SYNTAX_COMMENT_STYLE (FETCH_CHAR (from)) == comstyle)
+ break;
+
+ /* Assume a defun-start point is outside of strings. */
+ if (code == Sopen
+ && (from == stop || FETCH_CHAR (from - 1) == '\n'))
+ break;
+ }
+
+ if (comstart_pos == 0)
+ from = comment_end;
+ /* If the earliest comment starter
+ is followed by uniform paired string quotes or none,
+ we know it can't be inside a string
+ since if it were then the comment ender would be inside one.
+ So it does start a comment. Skip back to it. */
+ else if (comstart_parity == 0 && !string_lossage)
+ from = comstart_pos;
+ else
+ {
+ /* We had two kinds of string delimiters mixed up
+ together. Decode this going forwards.
+ Scan fwd from the previous comment ender
+ to the one in question; this records where we
+ last passed a comment starter. */
+ struct lisp_parse_state state;
+ scan_sexps_forward (&state, find_defun_start (comment_end),
+ comment_end - 1, -10000, 0, Qnil, 0);
+ if (state.incomment)
+ from = state.comstart;
+ else
+ /* We can't grok this as a comment; scan it normally. */
+ from = comment_end;
+ }
+ }
+ /* We have skipped one comment. */
+ break;
+ }
+ else if ((code != Swhitespace && code != Scomment) || quoted)
+ {
+ immediate_quit = 0;
+ SET_PT (from + 1);
+ return Qnil;
+ }
+ }
+
+ count1++;
+ }
+
+ SET_PT (from);
+ immediate_quit = 0;
+ return Qt;
+}
+\f
HCoop / bpt / emacs.git / blobdiff