diff options
| -rw-r--r-- | src/syntax.c | 128 |
1 files changed, 112 insertions, 16 deletions
diff --git a/src/syntax.c b/src/syntax.c index aa40547ba5a..81b02a603c8 100644 --- a/src/syntax.c +++ b/src/syntax.c @@ -45,6 +45,68 @@ struct lisp_parse_state int comstart; /* Position just after last comment starter. */ }; +/* These variables are a cache for finding the start of a defun. + find_start_pos is the place for which the defun start was found. + find_start_value is the defun start position found for it. + find_start_buffer is the buffer it was found in. + find_start_begv is the BEGV value when it was found. + find_start_modiff is the value of MODIFF when it was found. */ + +static int find_start_pos; +static int find_start_value; +static struct buffer *find_start_buffer; +static int find_start_begv; +static int find_start_modiff; + +/* Find a defun-start that is the last one before POS (or nearly the last). + We record what we find, so that another call in the same area + can return the same value right away. */ + +static int +find_defun_start (pos) + int pos; +{ + int tem; + int shortage; + + /* Use previous finding, if it's valid and applies to this inquiry. */ + if (current_buffer == find_start_buffer + /* Reuse the defun-start even if POS is a little farther on. + POS might be in the next defun, but that's ok. + Our value may not be the best possible, but will still be usable. */ + && pos <= find_start_pos + 1000 + && pos >= find_start_value + && BEGV == find_start_begv + && MODIFF == find_start_modiff) + return find_start_value; + + /* Back up to start of line. */ + tem = scan_buffer ('\n', pos, -1, &shortage); + /* If we found a newline, we moved back over it, so advance fwd past it. */ + if (shortage == 0) + tem++; + + while (tem > BEGV) + { + /* Open-paren at start of line means we found our defun-start. */ + if (SYNTAX (FETCH_CHAR (tem)) == Sopen) + break; + /* Move to beg of previous line. */ + tem = scan_buffer ('\n', tem, -2, &shortage); + if (shortage == 0) + tem++; + } + + /* Record what we found, for the next try. */ + find_start_value = tem; + find_start_buffer = current_buffer; + find_start_modiff = MODIFF; + find_start_begv = BEGV; + find_start_pos = pos; + + return find_start_value; +} + DEFUN ("syntax-table-p", Fsyntax_table_p, Ssyntax_table_p, 1, 1, 0, "Return t if ARG is a syntax table.\n\ Any vector of 256 elements will do.") @@ -750,6 +812,27 @@ scan_lists (from, count, depth, sexpflag) case Sendcomment: if (!parse_sexp_ignore_comments) break; + 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) goto done; + from--; + if (SYNTAX_COMSTART_SECOND (c) + && SYNTAX_COMSTART_FIRST (FETCH_CHAR (from)) + && SYNTAX_COMMENT_STYLE (c) == comstyle + && !char_quoted (from)) + break; + } + break; + } + /* 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; @@ -760,13 +843,12 @@ scan_lists (from, count, depth, sexpflag) which is I+2X quotes from the comment-end. PARITY is current parity of quotes from the comment end. */ { - int ofrom[2]; int parity = 0; char my_stringend = 0; int string_lossage = 0; int comment_end = from; - - ofrom[0] = ofrom[1] = from; + int comstart_pos = 0; + int comstart_parity = 0; /* At beginning of range to scan, we're outside of strings; that determines quote parity to the comment-end. */ @@ -799,13 +881,13 @@ scan_lists (from, count, depth, sexpflag) if (char_quoted (from)) continue; - /* Track parity of quotes between here and comment-end. */ + /* Track parity of quotes. */ if (code == Sstring) { parity ^= 1; if (my_stringend == 0) my_stringend = c; - /* We have two kinds of string delimiters. + /* 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; @@ -814,18 +896,34 @@ scan_lists (from, count, depth, sexpflag) /* Record comment-starters according to that quote-parity to the comment-end. */ if (code == Scomment) - ofrom[parity] = from; + { + comstart_parity = parity; + comstart_pos = from; + } - /* If we come to another comment-end, - assume it's not inside a string. - That determines the quote parity to the comment-end. - Note that the comment style this character ends must - match the style that we have begun */ + /* If we find another earlier comment-ender, + any comment-starts earier 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 (string_lossage) + + 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. @@ -833,16 +931,14 @@ scan_lists (from, count, depth, sexpflag) to the one in question; this records where we last passed a comment starter. */ struct lisp_parse_state state; - scan_sexps_forward (&state, from + 1, comment_end - 1, - -10000, 0, Qnil); + scan_sexps_forward (&state, find_defun_start (comment_end), + comment_end - 1, -10000, 0, Qnil); if (state.incomment) from = state.comstart; else /* We can't grok this as a comment; scan it normally. */ from = comment_end; } - else - from = ofrom[parity]; } break; |