mit-scheme.git
33 years agoAdded more summary mode commands.
Brian A. LaMacchia [Sun, 25 Aug 1991 21:37:58 +0000 (21:37 +0000)]
Added more summary mode commands.

33 years agoAdded more exports for RMAIL and RMAIL-Summary modes.
Brian A. LaMacchia [Sun, 25 Aug 1991 21:37:26 +0000 (21:37 +0000)]
Added more exports for RMAIL and RMAIL-Summary modes.

33 years agoInitial revision
Chris Hanson [Sat, 24 Aug 1991 02:30:54 +0000 (02:30 +0000)]
Initial revision

33 years agoChanges for apollo.
Chris Hanson [Sat, 24 Aug 1991 02:27:52 +0000 (02:27 +0000)]
Changes for apollo.

33 years agoChanges for apollo.
Chris Hanson [Sat, 24 Aug 1991 02:15:56 +0000 (02:15 +0000)]
Changes for apollo.

33 years agoFix typo.
Chris Hanson [Sat, 24 Aug 1991 02:10:15 +0000 (02:10 +0000)]
Fix typo.

33 years agoChange to match "ux.h".
Chris Hanson [Sat, 24 Aug 1991 01:51:14 +0000 (01:51 +0000)]
Change to match "ux.h".

33 years agoDefine CAST_FUNCTION_TO_INT_BUG.
Chris Hanson [Sat, 24 Aug 1991 01:47:51 +0000 (01:47 +0000)]
Define CAST_FUNCTION_TO_INT_BUG.

33 years agoMake Scheme explain why it cannot open a file.
Arthur Gleckler [Fri, 23 Aug 1991 23:26:48 +0000 (23:26 +0000)]
Make Scheme explain why it cannot open a file.

33 years agoAdd `#undef vax' for Vax compilation.
Chris Hanson [Fri, 23 Aug 1991 22:46:34 +0000 (22:46 +0000)]
Add `#undef vax' for Vax compilation.

33 years agoFix typo in BIT-STRING-REF that caused incorrect error message.
Chris Hanson [Fri, 23 Aug 1991 22:10:15 +0000 (22:10 +0000)]
Fix typo in BIT-STRING-REF that caused incorrect error message.

33 years agoFixed a bug in the generation of summary line.
Brian A. LaMacchia [Fri, 23 Aug 1991 18:11:02 +0000 (18:11 +0000)]
Fixed a bug in the generation of summary line.
Edwin always thought it had to build a new summary line.

33 years agoFix bug that caused init file to not be loaded if
Arthur Gleckler [Fri, 23 Aug 1991 16:25:14 +0000 (16:25 +0000)]
Fix bug that caused init file to not be loaded if
GET-UNUSED-COMMAND-LINE returned no command line options.

33 years agoInitial revision
Arthur Gleckler [Fri, 23 Aug 1991 14:49:13 +0000 (14:49 +0000)]
Initial revision

33 years agoFix think-o in case for MOVE-FRAME-UP.
Chris Hanson [Fri, 23 Aug 1991 09:15:03 +0000 (09:15 +0000)]
Fix think-o in case for MOVE-FRAME-UP.

33 years agoVarious small modifications.
Arthur Gleckler [Fri, 23 Aug 1991 02:38:27 +0000 (02:38 +0000)]
Various small modifications.

33 years agoUse relative pathnames so handling 300's and 800's is identical.
Arthur Gleckler [Fri, 23 Aug 1991 02:04:17 +0000 (02:04 +0000)]
Use relative pathnames so handling 300's and 800's is identical.

33 years agoChange command line processing to load the .scheme.init file (if there
Arthur Gleckler [Fri, 23 Aug 1991 01:27:06 +0000 (01:27 +0000)]
Change command line processing to load the .scheme.init file (if there
is not a -no-init-file option) before processing all the other
runtime-system-processed command line options.  This way, if an -eval
or -load option never returns, the .scheme.init file will have already
been processed.

33 years agoAdd SCROLL-OTHER-WINDOW-DOWN command and bind
Arthur Gleckler [Fri, 23 Aug 1991 00:24:48 +0000 (00:24 +0000)]
Add SCROLL-OTHER-WINDOW-DOWN command and bind

  M-prior to SCROLL-OTHER-WINDOW-DOWN
  M-next  to SCROLL-OTHER-WINDOW

33 years agoAdd ability to regenerate the 6.001 (student) band, with type- and
Arthur Gleckler [Thu, 22 Aug 1991 21:09:04 +0000 (21:09 +0000)]
Add ability to regenerate the 6.001 (student) band, with type- and
range-checking on in the runtime system.

33 years agoAdd make.scm to the list of files to syntax.
Arthur Gleckler [Thu, 22 Aug 1991 20:32:35 +0000 (20:32 +0000)]
Add make.scm to the list of files to syntax.

33 years agoGive RCS the correct version number for the 6.001 (student) system.
Arthur Gleckler [Thu, 22 Aug 1991 19:41:10 +0000 (19:41 +0000)]
Give RCS the correct version number for the 6.001 (student) system.

33 years agoChange compare-file-modification-times so that if foo.bin is linked to
Guillermo J. Rozas [Thu, 22 Aug 1991 18:17:27 +0000 (18:17 +0000)]
Change compare-file-modification-times so that if foo.bin is linked to
foo.scm, it won't be sf'd, etc.

33 years agoChange compare-file-modification-times so that if foo.bin is linked to
Guillermo J. Rozas [Thu, 22 Aug 1991 17:59:32 +0000 (17:59 +0000)]
Change compare-file-modification-times so that if foo.bin is linked to
foo.scm, it won't be sf'd, etc.

33 years agoActivate compiler type and range-checks.
Arthur Gleckler [Thu, 22 Aug 1991 17:56:31 +0000 (17:56 +0000)]
Activate compiler type and range-checks.

33 years agoInitial revision
Arthur Gleckler [Thu, 22 Aug 1991 17:44:50 +0000 (17:44 +0000)]
Initial revision

33 years ago(Arthur and Jinx:) Add special restarts for open-file errors.
Arthur Gleckler [Thu, 22 Aug 1991 15:43:39 +0000 (15:43 +0000)]
(Arthur and Jinx:) Add special restarts for open-file errors.

33 years ago(Arthur and Jinx:) Add special restarts for open-file errors.
Arthur Gleckler [Thu, 22 Aug 1991 15:19:05 +0000 (15:19 +0000)]
(Arthur and Jinx:) Add special restarts for open-file errors.

33 years agoNew directory organization.
Chris Hanson [Thu, 22 Aug 1991 01:17:20 +0000 (01:17 +0000)]
New directory organization.

33 years ago(Arthur and Jinx:) Add special restarts for open-file errors.
Chris Hanson [Thu, 22 Aug 1991 01:15:03 +0000 (01:15 +0000)]
(Arthur and Jinx:) Add special restarts for open-file errors.

33 years agoAdd rewriting rules for sony.
Chris Hanson [Thu, 22 Aug 1991 01:00:44 +0000 (01:00 +0000)]
Add rewriting rules for sony.

33 years agoUpdate for new directory structure.
Chris Hanson [Wed, 21 Aug 1991 20:04:52 +0000 (20:04 +0000)]
Update for new directory structure.

33 years agoExport sendmail variables MAIL-POSITION-ON-FIELD and
Arthur Gleckler [Wed, 21 Aug 1991 18:12:25 +0000 (18:12 +0000)]
Export sendmail variables MAIL-POSITION-ON-FIELD and
MAIL-POSITION-ON-CC-FIELD.

33 years agoAdd interrupt support and cleanup code.
Guillermo J. Rozas [Wed, 21 Aug 1991 17:48:27 +0000 (17:48 +0000)]
Add interrupt support and cleanup code.
Use the -no-init-file to avoid potential problems.
Lock against simultaneous build.

33 years agoMake fields of pretty-printer-highlight structure mutable.
Guillermo J. Rozas [Wed, 21 Aug 1991 16:57:02 +0000 (16:57 +0000)]
Make fields of pretty-printer-highlight structure mutable.

33 years agoExport RMAIL-REPLY command.
Arthur Gleckler [Wed, 21 Aug 1991 16:18:03 +0000 (16:18 +0000)]
Export RMAIL-REPLY command.

33 years agoFix bugs in rules for generating closures: these rules were assigning
Chris Hanson [Wed, 21 Aug 1991 04:14:25 +0000 (04:14 +0000)]
Fix bugs in rules for generating closures: these rules were assigning
to the assembler temporary, then executing an instruction that
sometimes used the temporary.

33 years agoFix several bugs in the rules for instructions with immediate
Chris Hanson [Wed, 21 Aug 1991 04:11:46 +0000 (04:11 +0000)]
Fix several bugs in the rules for instructions with immediate
operands.

33 years agoAdd the following command-line options to Scheme. They are processed
Arthur Gleckler [Tue, 20 Aug 1991 22:01:33 +0000 (22:01 +0000)]
Add the following command-line options to Scheme.  They are processed
before the init file (typically called ".scheme.init") is loaded:

  Option Keyword Effect
  -------------- ------

  -eval EVALuate the expressions following the keyword
in the USER-INITIAL-ENVIRONMENT, up to (but
not including) the next option that starts
with a hyphen.

  -load LOAD the files following the keyword, up to
(but not including) the next option that
starts with a hyphen.

  -no-init-file Do not load the init file.  Name chosen to be
consistent with Emacs.

33 years agoFix typo. Use typed errors.
Chris Hanson [Sun, 18 Aug 1991 23:33:20 +0000 (23:33 +0000)]
Fix typo.  Use typed errors.

33 years agoReplace 6 with scheme-type-width in do-multiply. Fix a comment.
Guillermo J. Rozas [Sun, 18 Aug 1991 14:47:31 +0000 (14:47 +0000)]
Replace 6 with scheme-type-width in do-multiply.  Fix a comment.

33 years agoFix unbound variable problem and make tables print a little prettier.
Guillermo J. Rozas [Sat, 17 Aug 1991 16:07:23 +0000 (16:07 +0000)]
Fix unbound variable problem and make tables print a little prettier.

33 years agoFix typo in `REGISTER->MEMORY-TRANSFER' that caused weird assembler
Chris Hanson [Sat, 17 Aug 1991 00:15:34 +0000 (00:15 +0000)]
Fix typo in `REGISTER->MEMORY-TRANSFER' that caused weird assembler
errors when the floating-point register set spilled.

33 years agoInitial revision
Arthur Gleckler [Fri, 16 Aug 1991 21:34:31 +0000 (21:34 +0000)]
Initial revision

33 years agoMake REGION-CLIP! guarantee that the point is in the narrowed region.
Arthur Gleckler [Fri, 16 Aug 1991 20:29:22 +0000 (20:29 +0000)]
Make REGION-CLIP! guarantee that the point is in the narrowed region.

33 years agoFix counting bug in maybe-print-table.
Guillermo J. Rozas [Fri, 16 Aug 1991 18:59:54 +0000 (18:59 +0000)]
Fix counting bug in maybe-print-table.

33 years agoRename (and invert) *pp-really-pretty?* to *pp-save-vertical-space?*
Guillermo J. Rozas [Fri, 16 Aug 1991 18:46:42 +0000 (18:46 +0000)]
Rename (and invert) *pp-really-pretty?* to *pp-save-vertical-space?*

33 years agoFix bug in maybe-print-table. It was ignoring depth and trying to
Guillermo J. Rozas [Fri, 16 Aug 1991 18:44:42 +0000 (18:44 +0000)]
Fix bug in maybe-print-table.  It was ignoring depth and trying to
tabulate less than 4 elements.
Rename (and invert) *pp-really-pretty?* to *pp-save-vertical-space?*

33 years agoNew (runtime hash) module supports multiple hash tables.
Guillermo J. Rozas [Fri, 16 Aug 1991 15:42:30 +0000 (15:42 +0000)]
New (runtime hash) module supports multiple hash tables.

33 years agoExport hash-table/make and object-hashed? from (runtime hash).
Guillermo J. Rozas [Fri, 16 Aug 1991 15:41:38 +0000 (15:41 +0000)]
Export hash-table/make and object-hashed? from (runtime hash).

33 years agoMultiple hash tables supported.
Guillermo J. Rozas [Fri, 16 Aug 1991 15:40:17 +0000 (15:40 +0000)]
Multiple hash tables supported.

33 years agoFix typo.
Guillermo J. Rozas [Fri, 16 Aug 1991 02:09:01 +0000 (02:09 +0000)]
Fix typo.

33 years agoAdd DEFAULT-WINDOW-WIDTH, the value returned by the X-SIZE operation
Arthur Gleckler [Fri, 16 Aug 1991 01:31:50 +0000 (01:31 +0000)]
Add DEFAULT-WINDOW-WIDTH, the value returned by the X-SIZE operation
on buffer output ports when the buffer does not appear in any window.

33 years agoUpdate pretty printer to include highlight objects, tabulation of data
Guillermo J. Rozas [Fri, 16 Aug 1991 01:21:21 +0000 (01:21 +0000)]
Update pretty printer to include highlight objects, tabulation of data
lists, better user control by means of exported variables, and more
consistent modes (data versus code).

33 years agoUpdated pretty printer exports control variables.
Guillermo J. Rozas [Fri, 16 Aug 1991 01:19:40 +0000 (01:19 +0000)]
Updated pretty printer exports control variables.

33 years agoAdd dependency of missing.c on config.h.
Chris Hanson [Thu, 15 Aug 1991 22:39:48 +0000 (22:39 +0000)]
Add dependency of missing.c on config.h.

33 years agoSony NEWS OS has frexp, floor, modf.
Gerald Jay Sussman [Thu, 15 Aug 1991 22:15:04 +0000 (22:15 +0000)]
Sony NEWS OS has frexp, floor, modf.

33 years agoFix rewriting paths to accomodate new directory structure.
Guillermo J. Rozas [Thu, 15 Aug 1991 19:13:42 +0000 (19:13 +0000)]
Fix rewriting paths to accomodate new directory structure.

33 years agoChange to match new directory configuration.
Chris Hanson [Thu, 15 Aug 1991 18:32:50 +0000 (18:32 +0000)]
Change to match new directory configuration.

33 years agoAdd fixnum bitwise-logical operations to list of primitives that
Chris Hanson [Wed, 14 Aug 1991 20:55:14 +0000 (20:55 +0000)]
Add fixnum bitwise-logical operations to list of primitives that
cannot be open-coded on the MIPS.

33 years agoAdd FLOATING-VECTOR-xxx primitives.
Guillermo J. Rozas [Wed, 14 Aug 1991 02:09:12 +0000 (02:09 +0000)]
Add FLOATING-VECTOR-xxx primitives.

33 years agoAdd FLOATING-VECTOR-LENGTH.
Guillermo J. Rozas [Wed, 14 Aug 1991 02:02:53 +0000 (02:02 +0000)]
Add FLOATING-VECTOR-LENGTH.

33 years ago- Incorporate some reader comments.
Guillermo J. Rozas [Wed, 14 Aug 1991 01:16:19 +0000 (01:16 +0000)]
- Incorporate some reader comments.

- Mention new MIPS OVERFLOW-TEST solution.

33 years agoChange command, variable, and mode definition macros to make them
newts [Tue, 13 Aug 1991 20:59:40 +0000 (20:59 +0000)]
Change command, variable, and mode definition macros to make them
expand into simple Scheme definitions.

33 years agoChange hppa_utility_table to be allocated dynamically rather than
Guillermo J. Rozas [Tue, 13 Aug 1991 18:23:38 +0000 (18:23 +0000)]
Change hppa_utility_table to be allocated dynamically rather than
statically.

33 years agoAdd options for 8.01 and 8.05.
Guillermo J. Rozas [Tue, 13 Aug 1991 18:19:38 +0000 (18:19 +0000)]
Add options for 8.01 and 8.05.

33 years agoWork around HP-UX 8.0's format for C procedure pointers (closures).
Guillermo J. Rozas [Tue, 13 Aug 1991 06:46:08 +0000 (06:46 +0000)]
Work around HP-UX 8.0's format for C procedure pointers (closures).

33 years agoFix typo.
Chris Hanson [Tue, 13 Aug 1991 06:20:37 +0000 (06:20 +0000)]
Fix typo.

33 years agoMake ANSI declaration use GNU EXFUN macro to allow non-ANSI compilers
Guillermo J. Rozas [Tue, 13 Aug 1991 05:46:06 +0000 (05:46 +0000)]
Make ANSI declaration use GNU EXFUN macro to allow non-ANSI compilers
to handle it.

33 years ago*** empty log message ***
Chris Hanson [Tue, 13 Aug 1991 02:31:32 +0000 (02:31 +0000)]
*** empty log message ***

33 years agoEliminate unused and unbound variables. Repaginate.
Chris Hanson [Tue, 13 Aug 1991 02:31:22 +0000 (02:31 +0000)]
Eliminate unused and unbound variables.  Repaginate.

33 years agoFix typo.
Chris Hanson [Tue, 13 Aug 1991 02:30:37 +0000 (02:30 +0000)]
Fix typo.

33 years agoAdded primitives HOSTNAME and FULL-HOSTNAME to get the short host name
Mark Friedman [Mon, 12 Aug 1991 22:16:02 +0000 (22:16 +0000)]
Added primitives HOSTNAME and FULL-HOSTNAME to get the short host name
and the full host name with domain.

33 years agoRewrite fixnum overflow tests to produce significantly better code.
Chris Hanson [Mon, 12 Aug 1991 22:15:22 +0000 (22:15 +0000)]
Rewrite fixnum overflow tests to produce significantly better code.
Now fixnum operations with overflow do SET-CURRENT-BRANCHES!
themselves, and OVERFLOW-TEST does nothing.

33 years agoFix various bugs in generation of LAP for addition and loading of
Chris Hanson [Mon, 12 Aug 1991 22:13:44 +0000 (22:13 +0000)]
Fix various bugs in generation of LAP for addition and loading of
constants.

33 years agoChange disassembly of EXTERNAL-LABEL to use (@PCR label) where
Chris Hanson [Mon, 12 Aug 1991 22:11:08 +0000 (22:11 +0000)]
Change disassembly of EXTERNAL-LABEL to use (@PCR label) where
possible.

33 years agoFix definitions of &triple-set-second! and &triple-set-third! .
Guillermo J. Rozas [Mon, 12 Aug 1991 13:38:39 +0000 (13:38 +0000)]
Fix definitions of &triple-set-second! and &triple-set-third! .
They were clobbering the wrong cxr!

33 years agoDired was unable to delete files appearing on the first line of its buffer.
Arthur Gleckler [Mon, 12 Aug 1991 03:14:36 +0000 (03:14 +0000)]
Dired was unable to delete files appearing on the first line of its buffer.

33 years agoFix two history-related bugs:
Guillermo J. Rozas [Sun, 11 Aug 1991 15:24:37 +0000 (15:24 +0000)]
Fix two history-related bugs:

- previous-history-offsets were being incorrectly computed in
make-intermediate-state.

- make-control-point was adding a new (join-stacklets) frame even when
there was one, therefore invalidating all previous-history-offsets
contained in the stream.  This latter bug was "fixed" by changing
control-point/element-stream to not include the last (join-stacklets)
frame.

33 years agoExport Edwin variables to the (edwin) package:
Arthur Gleckler [Fri, 9 Aug 1991 18:42:23 +0000 (18:42 +0000)]
Export Edwin variables to the (edwin) package:

  X-SCREEN-NAME-FORMAT
  X-SCREEN-ICON-NAME-FORMAT
  X-SCREEN-ICON-NAME-LENGTH

33 years agoMake dummy reduction be recognizable as such, rather than spuriously
Guillermo J. Rozas [Thu, 8 Aug 1991 19:54:33 +0000 (19:54 +0000)]
Make dummy reduction be recognizable as such, rather than spuriously
show up.

33 years agoMake most HP keyboard functions do something reasonable (i.e. related
Arthur Gleckler [Thu, 8 Aug 1991 19:00:04 +0000 (19:00 +0000)]
Make most HP keyboard functions do something reasonable (i.e. related
to their names).

33 years agoFix FILL-DIRED-BUFFER! bug that caused "~" command (and probably
Arthur Gleckler [Wed, 7 Aug 1991 19:09:03 +0000 (19:09 +0000)]
Fix FILL-DIRED-BUFFER! bug that caused "~" command (and probably
others) to fail.

33 years agoUpdates for autoloading.
Brian A. LaMacchia [Tue, 6 Aug 1991 22:58:51 +0000 (22:58 +0000)]
Updates for autoloading.

33 years agoAdded RMAIL Summary mode and RMAIL sort mode.
Brian A. LaMacchia [Tue, 6 Aug 1991 22:55:31 +0000 (22:55 +0000)]
Added RMAIL Summary mode and RMAIL sort mode.

33 years agoAdded RMAIL sort mode.
Brian A. LaMacchia [Tue, 6 Aug 1991 22:54:20 +0000 (22:54 +0000)]
Added RMAIL sort mode.

33 years agoFix joke brainos.
Arthur Gleckler [Tue, 6 Aug 1991 22:45:17 +0000 (22:45 +0000)]
Fix joke brainos.

33 years agoAdded RMAIL Summary mode and RMAIL sort mode.
Brian A. LaMacchia [Tue, 6 Aug 1991 22:41:24 +0000 (22:41 +0000)]
Added RMAIL Summary mode and RMAIL sort mode.

33 years agoAdded autoloads for RMAIL Summary mode.
Brian A. LaMacchia [Tue, 6 Aug 1991 22:39:52 +0000 (22:39 +0000)]
Added autoloads for RMAIL Summary mode.

33 years agoIt works! (well, at least the basic stuff)
Brian A. LaMacchia [Tue, 6 Aug 1991 22:18:41 +0000 (22:18 +0000)]
It works! (well, at least the basic stuff)

33 years agoHardware traps now preserve the history when the trap is known to have
Arthur Gleckler [Tue, 6 Aug 1991 22:15:35 +0000 (22:15 +0000)]
Hardware traps now preserve the history when the trap is known to have
occured in compiled code, since the history is perfectly well defined.

33 years agoDebugger improvements to show history for compiled code frames that
Arthur Gleckler [Tue, 6 Aug 1991 22:14:08 +0000 (22:14 +0000)]
Debugger improvements to show history for compiled code frames that
have it.

33 years agoThe last compiled-return-address frame before an interpreter frame has
Arthur Gleckler [Tue, 6 Aug 1991 22:13:25 +0000 (22:13 +0000)]
The last compiled-return-address frame before an interpreter frame has
valid history.

33 years agoUse with-history-disabled in with-new-history so that new evaluations
Arthur Gleckler [Tue, 6 Aug 1991 22:12:23 +0000 (22:12 +0000)]
Use with-history-disabled in with-new-history so that new evaluations
are guaranteed to have at least one interpreter return frame, thus
making the continuation parser work better in the presence of compiled
code.

with-new-history no longer tail-recurses into the thunk.

33 years agoDebugger now treats compiled-return-address frames with history
Arthur Gleckler [Tue, 6 Aug 1991 22:10:41 +0000 (22:10 +0000)]
Debugger now treats compiled-return-address frames with history
specially: The stack information for each is printed as if it had
its own reduction since the first reduction corresponds to the
interpreted expression that tail-recursed into the compiled code.

33 years agoJokes.
Arthur Gleckler [Tue, 6 Aug 1991 22:04:26 +0000 (22:04 +0000)]
Jokes.

33 years ago*** empty log message ***
Brian A. LaMacchia [Tue, 6 Aug 1991 20:56:02 +0000 (20:56 +0000)]
*** empty log message ***

33 years agoAdd support for special keys, including function keys and arrow keys,
Arthur Gleckler [Tue, 6 Aug 1991 18:12:28 +0000 (18:12 +0000)]
Add support for special keys, including function keys and arrow keys,
with bucky bits.

A key is either a CHAR or a SPECIAL-KEY.  SPECIAL-KEYs can be compared
using EQ?.

Support all the keys named in /usr/include/X11/keysym.h, using the
names X gives them (with few exceptions).

Rename most procedures for dealing with keys from "-char" to "-key" to
prevent confusion.

Requires microcode 11.91 or later because of changes to the X keyboard
event structure.

33 years agoFix unbound variable error from special key changes.
Arthur Gleckler [Tue, 6 Aug 1991 15:55:10 +0000 (15:55 +0000)]
Fix unbound variable error from special key changes.

33 years agoAdd support for special keys, including function keys and arrow keys,
Arthur Gleckler [Tue, 6 Aug 1991 15:40:55 +0000 (15:40 +0000)]
Add support for special keys, including function keys and arrow keys,
with bucky bits.

A key is either a CHAR or a SPECIAL-KEY.  SPECIAL-KEYs can be compared
using EQ?.

Support all the keys named in /usr/include/X11/keysym.h, using the
names X gives them (with few exceptions).

Rename most procedures for dealing with keys from "-char" to "-key" to
prevent confusion.

Requires microcode 11.91 or later because of changes to the X keyboard
event structure.