Date: 29 May 88 Message No: 004
To: TeX implementors and distributors
From: Barbara Beeton
Subject: TeX early-warning system: status report and TeX 2.92
Owing to a number of problems and general lack of time, this mailing list
has been moribund since the end of last year; the last message sent out
was number 3, dated 24 Dec 87. There have now been some developments
that should be communicated, so we'll try to get things started again.
As it's been so long since the last message, there are some new names on
the list, and I've also changed some addresses to try to keep up with
changes to gateways and other mailer idosyncrasies, I'd appreciate it
if you'd acknowledge your receipt of the message; the mailer doesn't
always say that an address is unreachable, especially if it's going
across network gateways.
Last week I received the following message from Don Knuth:
Date: 25 May 88 1911 PDT
From: Don Knuth <DEK@SAIL.Stanford.EDU>
Subject: Tex, aka Humpty Dumpty
(are you ready for this?)
Today I repaired five (5) bugs in TeX and two (2) in METAFONT,
thereby making TeX version 2.92 and MF version 1.4.
Five. Yes, five. Plus two is seven.
Quite a blow to any feelings of confidence I once had...
Two TeX bugs were reported, one by Robert Messer and one by Peter
Breitenlohner. The Messer bug appeared last month in TeXhax, where it was
analyzed by Chris Thompson: When I'm scanning a file name, I use the string
pool as a buffer, and this conflicts with use of the string to define a
new control sequence (if the file name contains a macro call that has
parameters that are undefined control sequences).
Following DRF's dictum, I tried to think if any other bugs of a similar
nature could occur; and indeed I noticed that another case arises if
\string or \meaning or \the or suchlike occur as part of the file name
being scanned. (In previous versions of TeX, constructions like "\input
X\jobname" worked, but only by sheer luck... the `X' was lost and combined
with the \jobname and that whole thing was rescanned... very kludgy and
certainly not what I intended nor would it work with \expandafter.)
While testing that, I noticed another strange thing you could do with
TeX version 2.91: Try typing \input\romannumeral6 to the ** prompt,
then say \end on the next line; TeX tries to open file ".tex", then it
tells you it has written a transcript file called "viTEXPUT".
I needed to patch the make_name_string routine when fixing the latter bug.
This is one of the routines that's often in a change file, so people may
have to make a small update to their change file when they install 2.92.
In summary, I found three bugs because of what Messer reported; luckily
I had to pay for only one of them. What about the others? Well,
Breitenlohner noticed that \patterns would fail if a pattern starts with a
character whose \lccode is 1. While fixing that, I noticed a weird
circumstance that would arise only if an extremely nasty user tried very
hard to cause a range error; thus, five bugs total.
Both METAFONT bugs were found by Chris Thompson. One was a typo,
easily fixed; the other was craftily contrived in the TRIP/TRAP mold
(I mean, it was not the sort of thing any reasonable person would ever
run into, yet it produced a bug natheless). No bugs had been found in
METAFONT for almost two years, so I had pretty much forgotten how
to install a new version!
Breitenlohner also pointed out an infelicity in PLAIN.TEX; I've updated
that too. To top it all off, another typo in the MFbook was reported.
The new sources at SAIL have new versions of TEX.WEB, MF.WEB, PLAIN.TEX,
and all the TRIP and TRAP files. ...
I've kept ERRATA.TEX[tex,dek] up to date, except that I didn't bother
to show all the changes to indexes and mini-indexes.
The files TEX82.BUG[tex,dek] and MF84.BUG[mf,dek] are also up to date.
As far as I know, everything at SAIL is now bugfree and self-consistent.
No amount of apologies can suffice for my stupidities reflected in
all these booboos.
...mumble seven new errors my my mumble seven SEVEN seven SEVEN my my
mumble seven...
A note seems in order on the reference to SAIL. SAIL (SAIL.Stanford.Edu)
is a DEC-10 running under the WAITS operating system; this is the system
on which Knuth works, and the files here are always the most up-to-date.
When Knuth sends out notice of a new version, the affected files are
transported to SCORE (SCORE.Stanford.Edu), a DEC-20 running under TOPS-20;
the generic distribution tape is generated here, as well as the TOPS-20
distribution. The TeX system files at SCORE are maintained and updated
by volunteers, who are not always able to react immediately to changes at
SAIL. Both SAIL and SCORE support anonymous FTP, and a later message will
provide more information on that.
Today's information will consist of the new entries in the TeX82.BUG file,
a comparison of the TeX.WEB files for version 2.92 and 2.9, and the changes
in PLAIN.TeX.
########################################################################
Additions to TeX82.BUG
338. \outer\def\a0{}\a\a shows temp_head list garbage (Silvio Levy, 20Apr88)
@x module 391
repeat if (info(r)>match_token+127)or(info(r)<match_token) then s:=null
else begin match_chr:=info(r)-match_token; s:=link(r); r:=s;
p:=temp_head; link(p):=null; m:=0;
@y
repeat link(temp_head):=null;
if (info(r)>match_token+127)or(info(r)<match_token) then s:=null
else begin match_chr:=info(r)-match_token; s:=link(r); r:=s;
p:=temp_head; m:=0;
@z
339. \def\\#1{}\input a\\b failed (Robert Messer, 24Apr88)
@x module 259
var h:integer; {hash code}
@y
var h:integer; {hash code}
@!d:integer; {number of characters in incomplete current string}
@z
@x module 260
str_room(l);
for k:=j to j+l-1 do append_char(buffer[k]);
text(p):=make_string;
@y
str_room(l); d:=cur_length;
while pool_ptr>str_start[str_ptr] do
begin decr(pool_ptr); str_pool[pool_ptr+l]:=str_pool[pool_ptr];
end; {move current string up to make room for another}
for k:=j to j+l-1 do append_char(buffer[k]);
text(p):=make_string; pool_ptr:=pool_ptr+d;
@z
340. Make patterns work when trie_min=0 (Peter Breitenlohner, 10May88)
@x module 951
trie_max:=128; trie_min:=128; trie_link(0):=1; trie_taken[0]:=false;
@y
trie_max:=128; trie_min:=128; trie_link(0):=1; trie_taken[0]:=false;
trie_link(trie_size):=0; trie_back(0):=trie_size; {wrap around}
@z
@x module 953
begin c:=trie_c[p]; {we have |c>0|}
if c<trie_min then trie_min:=c;
z:=trie_link(trie_min-1); {get the first conceivably good hole}
@y
begin c:=trie_c[p];
if c<trie_min then trie_min:=c;
if trie_min=0 then z:=trie_link(trie_size)
else z:=trie_link(trie_min-1); {get the first conceivably good hole}
@z
@x module 966
r:=0; {finally, we will zero out the holes}
@y
r:=trie_size; {finally, we will zero out the holes}
@z
341. Avoid possible trie_pointer out of range (24May88)
@x module 923
hc[0]:=127; hc[hn+1]:=127; hc[hn+2]:=256; {insert delimiters}
@y
hc[0]:=127; hc[hn+1]:=127; hc[hn+2]:=128; {insert delimiters}
@z
342. \input a\romannumeral1 etc.; similar to bug 339. (25May88)
@x module 464
@p function str_toks:pointer; {changes the current string to a token list}
@y
@p function str_toks(@!b:pool_pointer):pointer;
{changes the string |str_pool[b..pool_ptr]| to a token list}
@z
@x module 464, continued
p:=temp_head; link(p):=null; k:=str_start[str_ptr];
@y
p:=temp_head; link(p):=null; k:=b;
@z
@x module 464, concluded
pool_ptr:=str_start[str_ptr]; str_toks:=p;
@y
pool_ptr:=b; str_toks:=p;
@z
@x module 465
begin get_x_token; scan_something_internal(tok_val,false);
if cur_val_level>=ident_val then @<Copy the token list@>
else begin old_setting:=selector; selector:=new_string;
@y
@!b:pool_pointer; {base of temporary string}
begin get_x_token; scan_something_internal(tok_val,false);
if cur_val_level>=ident_val then @<Copy the token list@>
else begin old_setting:=selector; selector:=new_string; b:=pool_ptr;
@z
@x module 465, continued
selector:=old_setting; the_toks:=str_toks;
@y
selector:=old_setting; the_toks:=str_toks(b);
@z
@x module 470
begin c:=cur_chr; @<Scan the argument for command |c|@>;
old_setting:=selector; selector:=new_string;
@<Print the result of command |c|@>;
selector:=old_setting; link(garbage):=str_toks; ins_list(link(temp_head));
@y
@!b:pool_pointer; {base of temporary string}
begin c:=cur_chr; @<Scan the argument for command |c|@>;
old_setting:=selector; selector:=new_string; b:=pool_ptr;
@<Print the result of command |c|@>;
selector:=old_setting; link(garbage):=str_toks(b); ins_list(link(temp_head));
@z
343. **\input\romannumeral6 confusion bypassed (25May88)
@x module 525
begin if (pool_ptr+name_length>pool_size)or(str_ptr=max_strings) then
@y
begin if (pool_ptr+name_length>pool_size)or(str_ptr=max_strings)or
(cur_length>0) then
@z
344. (I sincerely hope that there won't be any more)
########################################################################
Differences between TeX.WEB for 2.92 and for 2.9
;COMPARISON OF TX:<TEX82.NEW>TEX-2-92.WEB.1 AND TX:<TEX82.NEW>TEX-2-9.WEB.1
;OPTIONS ARE /E /3
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 1-28 (1880)
% Version 2.91 fixes \outer\def\a0{}\a\a bug (April 1988).
% Version 2.92 fixes \patterns, also file names with complex macros (May 1988).
% A reward of $81.92 will be paid to the first finder of any remaining bug.
% (This amount will double again in 1989.)
% Although considerable effort has been expended to make the TeX program
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 1-29 (1882)
% A reward of $40.96 will be paid to the first finder of any remaining bug.
% (This amount will double again in 1988.)
% Although considerable effort has been expended to make the TeX program
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 2-93 (9207)
@d banner=='This is TeX, Version 2.92' {printed when \TeX\ starts}
@ Different \PASCAL s have slightly different conventions, and the present
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 2-93 (9066)
@d banner=='This is TeX, Version 2.9' {printed when \TeX\ starts}
@ Different \PASCAL s have slightly different conventions, and the present
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 19-61 (240552)
@!d:integer; {number of characters already in current string}
@!p:pointer; {index in |hash| array}
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 19-61 (240410)
@!p:pointer; {index in |hash| array}
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 19-88 (241492)
str_room(l); d:=cur_length;
while pool_ptr>str_start[str_ptr] do
begin decr(pool_ptr); str_pool[pool_ptr+l]:=str_pool[pool_ptr];
end; {move current string up to make room for another}
for k:=j to j+l-1 do append_char(buffer[k]);
text(p):=make_string; pool_ptr:=pool_ptr+d;
@!stat incr(cs_count);@+tats@;@/
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 19-87 (241287)
str_room(l);
for k:=j to j+l-1 do append_char(buffer[k]);
text(p):=make_string;
@!stat incr(cs_count);@+tats@;@/
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 20-77 (255280)
@!group_code=0..max_group_code; {|save_level| for a level boundary}
@ The global variable |cur_group| keeps track of what sort of group we are
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 20-77 (254875)
@!group_code=0..max_group_code; {|save_index| for a level boundary}
@ The global variable |cur_group| keeps track of what sort of group we are
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 25-31 (308968)
@!par_token:halfword; {token representing `\.{\\par}'}
@ @<Put each...@>=
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 25-31 (308563)
@!par_token:halfword; {token representing '\.{\\par}'}
@ @<Put each...@>=
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 25-372 (322487)
@ The present point in the program is reached only when the |expand|
routine has inserted a special marker into the input. In this special
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 25-372 (322082)
@ The present point in the program is reached only when the |no_expand|
routine has inserted a special marker into the input. In this special
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 26-375 (343630)
repeat link(temp_head):=null;
if (info(r)>match_token+127)or(info(r)<match_token) then s:=null
else begin match_chr:=info(r)-match_token; s:=link(r); r:=s;
p:=temp_head; m:=0;
end;
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 26-375 (343228)
repeat if (info(r)>match_token+127)or(info(r)<match_token) then s:=null
else begin match_chr:=info(r)-match_token; s:=link(r); r:=s;
p:=temp_head; link(p):=null; m:=0;
end;
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 27-675 (378115)
are |x| sp per unit; |goto attach_sign| if the units are internal@>;
@<Scan an optional space@>;
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 27-675 (377704)
are |x| units per sp; |goto attach_sign| if the units are internal@>;
@<Scan an optional space@>;
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 28-13 (388583)
@p function str_toks(@!b:pool_pointer):pointer;
{changes the string |str_pool[b..pool_ptr]| to a token list}
var p:pointer; {tail of the token list}
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 28-13 (388173)
@p function str_toks:pointer; {changes the current string to a token list}
var p:pointer; {tail of the token list}
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 28-20 (388915)
p:=temp_head; link(p):=null; k:=b;
while k<pool_ptr do
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 28-19 (388468)
p:=temp_head; link(p):=null; k:=str_start[str_ptr];
while k<pool_ptr do
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 28-28 (389103)
pool_ptr:=b; str_toks:=p;
end;
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 28-27 (388673)
pool_ptr:=str_start[str_ptr]; str_toks:=p;
end;
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 28-40 (389611)
@!b:pool_pointer; {base of temporary string}
begin get_x_token; scan_something_internal(tok_val,false);
if cur_val_level>=ident_val then @<Copy the token list@>
else begin old_setting:=selector; selector:=new_string; b:=pool_ptr;
case cur_val_level of
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 28-39 (389198)
begin get_x_token; scan_something_internal(tok_val,false);
if cur_val_level>=ident_val then @<Copy the token list@>
else begin old_setting:=selector; selector:=new_string;
case cur_val_level of
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 28-53 (390161)
selector:=old_setting; the_toks:=str_toks(b);
end;
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 28-51 (389689)
selector:=old_setting; the_toks:=str_toks;
end;
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 28-117 (392508)
@!b:pool_pointer; {base of temporary string}
begin c:=cur_chr; @<Scan the argument for command |c|@>;
old_setting:=selector; selector:=new_string; b:=pool_ptr;
@<Print the result of command |c|@>;
selector:=old_setting; link(garbage):=str_toks(b); ins_list(link(temp_head));
end;
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 28-115 (392033)
begin c:=cur_chr; @<Scan the argument for command |c|@>;
old_setting:=selector; selector:=new_string;
@<Print the result of command |c|@>;
selector:=old_setting; link(garbage):=str_toks; ins_list(link(temp_head));
end;
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 30-262 (427879)
begin if (pool_ptr+name_length>pool_size)or(str_ptr=max_strings)or
(cur_length>0) then
make_name_string:="?"
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 30-262 (427342)
begin if (pool_ptr+name_length>pool_size)or(str_ptr=max_strings) then
make_name_string:="?"
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 31-621 (464580)
@d check_byte_range(#)==begin if (#<bc)or<(#>ec) then abort@+end
@d current_character_being_worked_on==k+bc-fmem_ptr
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 31-621 (464024)
@d check_byte_range(#)==begin if (#<bc)or(#>ec) then abort@+end
@d current_character_being_worked_on==k+bc-fmem_ptr
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 35-281 (573403)
`\.\_' or `\.\^' or `\./' or `\.\\' if |p| is descended from the |subscr|
or |supscr| or |denominator| or |numerator| fields of noads. For example,
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 35-281 (572846)
`\.[' or `\.(' or `\./' or `\.\\' if |p| is descended from the |subscr|
or |supscr| or |denominator| or |numerator| fields of noads. For example,
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 43-68 (756339)
to the impossible value 128, in order to guarantee that |hc[hn+3]| will
never be fetched.
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 43-68 (755780)
to the impossible value 256, in order to guarantee that |hc[hn+3]| will
never be fetched.
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 43-75 (756649)
hc[0]:=127; hc[hn+1]:=127; hc[hn+2]:=128; {insert delimiters}
for j:=0 to hn-2 do
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 43-75 (756090)
hc[0]:=127; hc[hn+1]:=127; hc[hn+2]:=256; {insert delimiters}
for j:=0 to hn-2 do
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 43-196 (761319)
until coming to a right brace; then |return|@>;
exit:end;
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 43-196 (760760)
until coming to a right brace; then skip an optional space and |return|@>;
exit:end;
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 44-201 (773038)
trie_link(trie_size):=0; trie_back(0):=trie_size; {wrap around}
for p:=1 to 128 do
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 44-201 (772506)
for p:=1 to 128 do
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 44-233 (774482)
begin c:=trie_c[p];
if c<trie_min then trie_min:=c;
if trie_min=0 then z:=trie_link(trie_size)
else z:=trie_link(trie_min-1); {get the first conceivably good hole}
loop@+ begin if z<c then goto not_found;
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 44-232 (773885)
begin c:=trie_c[p]; {we have |c>0|}
if c<trie_min then trie_min:=c;
z:=trie_link(trie_min-1); {get the first conceivably good hole}
loop@+ begin if z<c then goto not_found;
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 44-345 (779179)
brace@>;
trie_root:=compress_trie(trie_root); {compress the trie}
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 44-343 (778549)
brace; then skip an optional space@>;
trie_root:=compress_trie(trie_root); {compress the trie}
***************
**** FILE TX:<TEX82.NEW>TEX-2-92.WEB.1, 44-443 (782387)
r:=trie_size; {finally, we will zero out the holes}
h.rh:=0; h.b0:=min_quarterword; h.b1:=0; {|trie_link:=0|,
**** FILE TX:<TEX82.NEW>TEX-2-9.WEB.1, 44-441 (781786)
r:=0; {finally, we will zero out the holes}
h.rh:=0; h.b0:=min_quarterword; h.b1:=0; {|trie_link:=0|,
***************
########################################################################
Differences between new and previous Plain.TeX
;COMPARISON OF PS:<TEX.INPUTS>PLAIN.TEX.2 AND PS:<TEX.INPUTS>PLAIN.TEX.1
;OPTIONS ARE /3
**** FILE PS:<TEX.INPUTS>PLAIN.TEX.2, 6-244 (33253)
\def\arrowvert{\delimiter"33C000 } % arrow without arrowheads
\def\Arrowvert{\delimiter"33D000 } % double arrow without arrowheads
\def\bracevert{\delimiter"33E000 } % the vertical bar that extends braces
**** FILE PS:<TEX.INPUTS>PLAIN.TEX.1, 1-951 (33258)
\def\arrowvert{\delimiter"33C } % arrow without arrowheads
\def\Arrowvert{\delimiter"33D } % double arrow without arrowheads
\def\bracevert{\delimiter"33E } % the vertical bar that extends braces
***************
**** FILE PS:<TEX.INPUTS>PLAIN.TEX.2, 8-22 (44482)
\def\fmtname{plain}\def\fmtversion{2.92} % identifies the current format
**** FILE PS:<TEX.INPUTS>PLAIN.TEX.1, 1-1220 (44480)
\def\fmtname{plain}\def\fmtversion{2.3} % identifies the current format
***************
########################################################################
[ end of message 004 ]
-------