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Commit e5d4f4dc authored by Richard M. Stallman's avatar Richard M. Stallman
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(scan_lists): Improve smarts for backwards scan of comments. 

Don't modify comstyle inside that loop.
If string quotes don't match up, don't take value from OFROM;
instead, parse forward using scan_sexps_forward.
(scan_sexps_forward): Return value via a pointer passed in.
New element in state contains char addr of last comment-starter seen.
(Fparse_partial_sexp): Change call to scan_sexps_forward.
parent a4d4c819
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Showing with 174 additions and 56 deletions
src/syntax.c
View file @ e5d4f4dc
......@@ -29,6 +29,22 @@ Lisp_Object Qsyntax_table_p;
int words_include_escapes;
/* This is the internal form of the parse state used in parse-partial-sexp. */
struct lisp_parse_state
{
int depth; /* Depth at end of parsing */
int instring; /* -1 if not within string, else desired terminator. */
int incomment; /* Nonzero if within a comment at end of parsing */
int comstyle; /* comment style a=0, or b=1 */
int quoted; /* Nonzero if just after an escape char at end of parsing */
int thislevelstart; /* Char number of most recent start-of-expression at current level */
int prevlevelstart; /* Char number of start of containing expression */
int location; /* Char number at which parsing stopped. */
int mindepth; /* Minimum depth seen while scanning. */
int comstart; /* Position just after last comment starter. */
};
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.")
......@@ -170,13 +186,21 @@ Two-character sequences are represented as described below.\n\
The second character of S is the matching parenthesis,\n\
used only if the first character is `(' or `)'.\n\
Any additional characters are flags.\n\
Defined flags are the characters 1, 2, 3, 4, and p.\n\
Defined flags are the characters 1, 2, 3, 4, b, and p.\n\
1 means C is the start of a two-char comment start sequence.\n\
2 means C is the second character of such a sequence.\n\
3 means C is the start of a two-char comment end sequence.\n\
4 means C is the second character of such a sequence.\n\
p means C is a prefix character for `backward-prefix-chars';
such characters are treated as whitespace when they occur
\n\
There can be up to two orthogonal comment sequences. This is to support\n\
language modes such as C++. By default, all comment sequences are of style\n\
a, but you can set the comment sequence style to b (on the second character of a\n\
comment-start, or the first character of a comment-end sequence) by using\n\
this flag:\n\
b means C is part of comment sequence b.\n\
\n\
p means C is a prefix character for `backward-prefix-chars';\n\
such characters are treated as whitespace when they occur\n\
between expressions.")
*/
......@@ -233,6 +257,10 @@ DEFUN ("modify-syntax-entry", Fmodify_syntax_entry, Smodify_syntax_entry, 2, 3,
case 'p':
XFASTINT (val) |= 1 << 20;
break;
case 'b':
XFASTINT (val) |= 1 << 21;
break;
}
XVECTOR (syntax_table)->contents[0xFF & XINT (c)] = val;
......@@ -246,7 +274,7 @@ describe_syntax (value)
Lisp_Object value;
{
register enum syntaxcode code;
char desc, match, start1, start2, end1, end2, prefix;
char desc, match, start1, start2, end1, end2, prefix, comstyle;
char str[2];
Findent_to (make_number (16), make_number (1));
......@@ -264,6 +292,7 @@ describe_syntax (value)
end1 = (XINT (value) >> 18) & 1;
end2 = (XINT (value) >> 19) & 1;
prefix = (XINT (value) >> 20) & 1;
comstyle = (XINT (value) >> 21) & 1;
if ((int) code < 0 || (int) code >= (int) Smax)
{
......@@ -291,6 +320,8 @@ describe_syntax (value)
if (prefix)
insert ("p", 1);
if (comstyle)
insert ("b", 1);
insert_string ("\twhich means: ");
......@@ -348,6 +379,9 @@ describe_syntax (value)
insert_string (",\n\t is the first character of a comment-end sequence");
if (end2)
insert_string (",\n\t is the second character of a comment-end sequence");
if (comstyle)
insert_string (" (comment style b)");
if (prefix)
insert_string (",\n\t is a prefix character for `backward-prefix-chars'");
......@@ -489,6 +523,7 @@ scan_lists (from, count, depth, sexpflag)
int mathexit = 0;
register enum syntaxcode code;
int min_depth = depth; /* Err out if depth gets less than this. */
int comstyle = 0; /* style of comment encountered */
if (depth > 0) min_depth = 0;
......@@ -501,12 +536,22 @@ scan_lists (from, count, depth, sexpflag)
while (from < stop)
{
c = FETCH_CHAR (from);
code = SYNTAX(c);
code = SYNTAX (c);
from++;
if (from < stop && SYNTAX_COMSTART_FIRST (c)
&& SYNTAX_COMSTART_SECOND (FETCH_CHAR (from))
&& parse_sexp_ignore_comments)
code = Scomment, 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++;
}
if (SYNTAX_PREFIX (c))
continue;
......@@ -528,9 +573,9 @@ scan_lists (from, count, depth, sexpflag)
while (from < stop)
{
#ifdef SWITCH_ENUM_BUG
switch ((int) SYNTAX(FETCH_CHAR (from)))
switch ((int) SYNTAX (FETCH_CHAR (from)))
#else
switch (SYNTAX(FETCH_CHAR (from)))
switch (SYNTAX (FETCH_CHAR (from)))
#endif
{
case Scharquote:
......@@ -554,11 +599,20 @@ scan_lists (from, count, depth, sexpflag)
while (1)
{
if (from == stop) goto done;
if (SYNTAX (c = FETCH_CHAR (from)) == Sendcomment)
c = FETCH_CHAR (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;
from++;
if (from < stop && SYNTAX_COMEND_FIRST (c)
&& SYNTAX_COMEND_SECOND (FETCH_CHAR (from)))
&& 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; }
}
break;
......@@ -593,9 +647,9 @@ scan_lists (from, count, depth, sexpflag)
if (from >= stop) goto lose;
if (FETCH_CHAR (from) == stringterm) break;
#ifdef SWITCH_ENUM_BUG
switch ((int) SYNTAX(FETCH_CHAR (from)))
switch ((int) SYNTAX (FETCH_CHAR (from)))
#else
switch (SYNTAX(FETCH_CHAR (from)))
switch (SYNTAX (FETCH_CHAR (from)))
#endif
{
case Scharquote:
......@@ -635,7 +689,15 @@ scan_lists (from, count, depth, sexpflag)
&& SYNTAX_COMEND_FIRST (FETCH_CHAR (from - 1))
&& !char_quoted (from - 1)
&& parse_sexp_ignore_comments)
code = Sendcomment, from--;
{
/* 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 (SYNTAX_PREFIX (c))
continue;
......@@ -654,9 +716,9 @@ scan_lists (from, count, depth, sexpflag)
quoted = char_quoted (from - 1);
if (quoted)
from--;
if (! (quoted || SYNTAX(FETCH_CHAR (from - 1)) == Sword
|| SYNTAX(FETCH_CHAR (from - 1)) == Ssymbol
|| SYNTAX(FETCH_CHAR (from - 1)) == Squote))
if (! (quoted || SYNTAX (FETCH_CHAR (from - 1)) == Sword
|| SYNTAX (FETCH_CHAR (from - 1)) == Ssymbol
|| SYNTAX (FETCH_CHAR (from - 1)) == Squote))
goto done2;
from--;
}
......@@ -700,6 +762,9 @@ scan_lists (from, count, depth, sexpflag)
{
int ofrom[2];
int parity = 0;
char my_stringend = 0;
int string_lossage = 0;
int comment_end = from;
ofrom[0] = ofrom[1] = from;
......@@ -717,10 +782,18 @@ scan_lists (from, count, depth, sexpflag)
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--;
{
code = Sendcomment;
from--;
}
else if (from > stop && SYNTAX_COMSTART_SECOND (c)
&& SYNTAX_COMSTART_FIRST (FETCH_CHAR (from - 1)))
code = Scomment, from--;
&& SYNTAX_COMSTART_FIRST (FETCH_CHAR (from - 1))
&& comstyle == SYNTAX_COMMENT_STYLE (c))
{
code = Scomment;
from--;
}
/* Ignore escaped characters. */
if (char_quoted (from))
......@@ -728,7 +801,15 @@ scan_lists (from, count, depth, sexpflag)
/* Track parity of quotes between here and comment-end. */
if (code == Sstring)
parity ^= 1;
{
parity ^= 1;
if (my_stringend == 0)
my_stringend = c;
/* 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. */
......@@ -737,11 +818,31 @@ scan_lists (from, count, depth, sexpflag)
/* If we come to another comment-end,
assume it's not inside a string.
That determines the quote parity to the comment-end. */
if (code == Sendcomment)
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 (code == Sendcomment
&& SYNTAX_COMMENT_STYLE (FETCH_CHAR (from)) == comstyle)
break;
}
from = ofrom[parity];
if (string_lossage)
{
/* 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, from + 1, 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;
......@@ -858,26 +959,13 @@ This includes chars with \"quote\" or \"prefix\" syntax (' or p).")
return Qnil;
}
struct lisp_parse_state
{
int depth; /* Depth at end of parsing */
int instring; /* -1 if not within string, else desired terminator. */
int incomment; /* Nonzero if within a comment at end of parsing */
int quoted; /* Nonzero if just after an escape char at end of parsing */
int thislevelstart; /* Char number of most recent start-of-expression at current level */
int prevlevelstart; /* Char number of start of containing expression */
int location; /* Char number at which parsing stopped. */
int mindepth; /* Minimum depth seen while scanning. */
};
/* Parse forward from FROM to END,
assuming that FROM is the start of a function,
and return a description of the state of the parse at END. */
struct lisp_parse_state val_scan_sexps_forward;
assuming that FROM has state OLDSTATE (nil means FROM is start of function),
and return a description of the state of the parse at END.
If STOPBEFORE is nonzero, stop at the start of an atom. */
struct lisp_parse_state *
scan_sexps_forward (from, end, targetdepth, stopbefore, oldstate)
scan_sexps_forward (stateptr, from, end, targetdepth, stopbefore, oldstate)
struct lisp_parse_state *stateptr;
register int from;
int end, targetdepth, stopbefore;
Lisp_Object oldstate;
......@@ -905,6 +993,7 @@ scan_sexps_forward (from, end, targetdepth, stopbefore, oldstate)
depth = 0;
state.instring = -1;
state.incomment = 0;
state.comstyle = 0; /* comment style a by default */
}
else
{
......@@ -927,6 +1016,14 @@ scan_sexps_forward (from, end, targetdepth, stopbefore, oldstate)
oldstate = Fcdr (oldstate);
tem = Fcar (oldstate);
start_quoted = !NILP (tem);
/* if the eight element of the list is nil, we are in comment
style a. if it is non-nil, we are in comment style b */
oldstate = Fcdr (oldstate);
oldstate = Fcdr (oldstate);
oldstate = Fcdr (oldstate);
tem = Fcar (oldstate);
state.comstyle = !NILP (tem);
}
state.quoted = 0;
mindepth = depth;
......@@ -946,11 +1043,19 @@ scan_sexps_forward (from, end, targetdepth, stopbefore, oldstate)
while (from < end)
{
code = SYNTAX(FETCH_CHAR (from));
code = SYNTAX (FETCH_CHAR (from));
from++;
if (from < end && SYNTAX_COMSTART_FIRST (FETCH_CHAR (from - 1))
&& SYNTAX_COMSTART_SECOND (FETCH_CHAR (from)))
code = Scomment, from++;
&& SYNTAX_COMSTART_SECOND (FETCH_CHAR (from)))
{
/* Record the comment style we have entered so that only
the comment-end sequence of the same style actually
terminates the comment section. */
code = Scomment;
state.comstyle = SYNTAX_COMMENT_STYLE (FETCH_CHAR (from));
from++;
}
if (SYNTAX_PREFIX (FETCH_CHAR (from - 1)))
continue;
#ifdef SWITCH_ENUM_BUG
......@@ -976,9 +1081,9 @@ scan_sexps_forward (from, end, targetdepth, stopbefore, oldstate)
while (from < end)
{
#ifdef SWITCH_ENUM_BUG
switch ((int) SYNTAX(FETCH_CHAR (from)))
switch ((int) SYNTAX (FETCH_CHAR (from)))
#else
switch (SYNTAX(FETCH_CHAR (from)))
switch (SYNTAX (FETCH_CHAR (from)))
#endif
{
case Scharquote:
......@@ -1001,18 +1106,29 @@ scan_sexps_forward (from, end, targetdepth, stopbefore, oldstate)
case Scomment:
state.incomment = 1;
state.comstart = from;
startincomment:
while (1)
{
if (from == end) goto done;
if (SYNTAX (prev = FETCH_CHAR (from)) == Sendcomment)
prev = FETCH_CHAR (from);
if (SYNTAX (prev) == Sendcomment
&& SYNTAX_COMMENT_STYLE (prev) == state.comstyle)
/* Only terminate the comment section if the endcomment
of the same style as the start sequence has been
encountered. */
break;
from++;
if (from < end && SYNTAX_COMEND_FIRST (prev)
&& SYNTAX_COMEND_SECOND (FETCH_CHAR (from)))
&& SYNTAX_COMEND_SECOND (FETCH_CHAR (from))
&& SYNTAX_COMMENT_STYLE (prev) == state.comstyle)
/* Only terminate the comment section if the end-comment
sequence of the same style as the start sequence has
been encountered. */
{ from++; break; }
}
state.incomment = 0;
state.comstyle = 0; /* reset the comment style */
break;
case Sopen:
......@@ -1047,9 +1163,9 @@ scan_sexps_forward (from, end, targetdepth, stopbefore, oldstate)
if (from >= end) goto done;
if (FETCH_CHAR (from) == state.instring) break;
#ifdef SWITCH_ENUM_BUG
switch ((int) SYNTAX(FETCH_CHAR (from)))
switch ((int) SYNTAX (FETCH_CHAR (from)))
#else
switch (SYNTAX(FETCH_CHAR (from)))
switch (SYNTAX (FETCH_CHAR (from)))
#endif
{
case Scharquote:
......@@ -1086,8 +1202,7 @@ scan_sexps_forward (from, end, targetdepth, stopbefore, oldstate)
state.location = from;
immediate_quit = 0;
val_scan_sexps_forward = state;
return &val_scan_sexps_forward;
*stateptr = state;
}
/* This comment supplies the doc string for parse-partial-sexp,
......@@ -1100,7 +1215,7 @@ Parsing stops at TO or when certain criteria are met;\n\
point is set to where parsing stops.\n\
If fifth arg STATE is omitted or nil,\n\
parsing assumes that FROM is the beginning of a function.\n\
Value is a list of seven elements describing final state of parsing:\n\
Value is a list of eight elements describing final state of parsing:\n\
1. depth in parens.\n\
2. character address of start of innermost containing list; nil if none.\n\
3. character address of start of last complete sexp terminated.\n\
......@@ -1109,6 +1224,7 @@ Value is a list of seven elements describing final state of parsing:\n\
5. t if inside a comment.\n\
6. t if following a quote character.\n\
7. the minimum paren-depth encountered during this scan.\n\
8. t if in a comment of style `b'.\n\
If third arg TARGETDEPTH is non-nil, parsing stops if the depth\n\
in parentheses becomes equal to TARGETDEPTH.\n\
Fourth arg STOPBEFORE non-nil means stop when come to\n\
......@@ -1136,8 +1252,8 @@ DEFUN ("parse-partial-sexp", Fparse_partial_sexp, Sparse_partial_sexp, 2, 5, 0,
target = -100000; /* We won't reach this depth */
validate_region (&from, &to);
state = *scan_sexps_forward (XINT (from), XINT (to),
target, !NILP (stopbefore), oldstate);
scan_sexps_forward (&state, XINT (from), XINT (to),
target, !NILP (stopbefore), oldstate);
SET_PT (state.location);
......@@ -1147,7 +1263,9 @@ DEFUN ("parse-partial-sexp", Fparse_partial_sexp, Sparse_partial_sexp, 2, 5, 0,
Fcons (state.instring >= 0 ? make_number (state.instring) : Qnil,
Fcons (state.incomment ? Qt : Qnil,
Fcons (state.quoted ? Qt : Qnil,
Fcons (make_number (state.mindepth), Qnil)))))));
Fcons (make_number (state.mindepth),
Fcons (state.comstyle ? Qt : Qnil,
Qnil))))))));
}
init_syntax_once ()
......
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