$CASE/gen/ver_11/aareadme.genv11_history - Updated by RJL 990804: 

chgen version history since $CASE/gen/ver_10:
---------------------------------------------

$CASE/gen/ver_10 added an option -meta that emitted
metaschema table definitions to file input_schema.msdat
This is a .dat file containing the input_schema content 
stored as rows of tables SV, TT and TA, also Table TS
(Table Statistics (e.g., row-count of table TT etc.)
and table VV (View Version) (data from a metaschema 
viewdefs file that pr_init needs to read). 


Applications can read the .msdat file by using 
chgen library support. this has many ramifications:

In the most recent $CASE/99s523/genmerge project,  
KSpinney bootstrapped chgenv10 into a chgenv11 application;
genv10 provides a pr_* and metaschema.h library based on 
metaschema.sch that can be used by  genv11. 
Genv11 can call pr_load to load and then access the 
definitions of tables TT and TA  when it generates a 
new schema,h file and pr*.c code for the application.

Chgenv11 currently still navigates its hcg_structs 
(tt_list and ta_list) during code generation,
but chgenv12 will replacethese refs by references to its
new internal metatables TT and TA, after it (like genv10)
populates them by parsing the application schema.

gen/ver_10 created the library including metaschema.h and pr_*.c
and gen/ver_11 was built as a genv10 application linked
to the pr_loaded meta-data-base. Any application 
linked to the pr_* library generated by  gen/ver11 
has access to the definitions of its own database
tables as data. 

This reflective power is necessary so the pr_*.c library
code created by new chgenv11 routines in  src/gen_pr_log.c 
can interpret the ASCII fields of pr_set events
during log-file replay (see src/gen_pr_log.c).

The code in $CASE/99s523/genmerge/chgenv11/chgen/src 
also incorporates the latest version of code to support 
application data logging and replay. It has merged
this code from rrassman in $CASE/98f523  into the
CVS repository version of chgen.
See $CASE/99s523/genmerge/doc for test status and details.

--------------------------------------------------

Past History:

The first significant genlog project [see $CASE/gen/aareadme.genlog] 
was by Denise Nelson/Bill Rideout/Mike Murphy of GTE
but was not checked into CVS.

They created file  src/gen_pr_log.c which 
both logged and replayed pr_add/delete events to support 
entire record or table row add/deletes.

CTWang slightly extended that genlog project by also logging 
field updates (conditionally, inside new pr_set_* macros) 
but he did not provide support to replay pr_set* events.


RRassman  added routines to gen_pr_log.c which 
KSpinney/Jkarner later merged into $CASE/gen/ver_10log/chgen/src, 
(in $CASE/99s523/genmerge).  Now a pr_*.c library produced by 
$CASE/gen/ver_11 can replay pr_set events logged by ctwang's code.

An example of a logged data file is in 
	$CASE/gen/ver_10log/rrassman/enroll/enroll.txt 
(I linked this node to $CASE/98f/genreplay/rrassman - RJL 990804).
(This test extends the previous version in 
	$CASE/99s523/genmerge/chgenv11/chgen/test/enroll).

The 99s523/genmerge project added Rassman's new
log_do_set_* routines to file gen_pr_log.c within gen/ver_11.

----------------------------------------------------

Future Plans: Bdelog: (bde + genlog)
-------------

1. RRassman's version of genlog works for terminal emulator applications 
but not for bde which requires X11. 
Bde  currently lacks menu support for logging and replay.  
Yicheng Xu in $CASE/99s523/yxu is trying to modify bde to add log/replay 
and build it with rrassman's version to test the log/replay concept.

This involves at least:
(1) adding a WorkProcess  callback to X11 to read the log file input
and call functions pr_add/delete/set_* during bde replay; 
(2) getting around lack of bde GUI menu support  for log/replay.
(3) extension of BDE to multi-user distributed editing (DBDE)
through reuse of genv11's new logging and replay features.

2. The chgen-refactoring project will explore the use of ghost variables
during chgen code migration: to replace hcg_structs by tables TT and TA
throughout all existing chgen code modules  (eliminating hcg-structs).

3. Other future extensions of bde:
(1) Distributed bde
(2) Bde OO-menu extensions for log/replay flexibility.
(3) Add support for logging of mouse events and X11 event history.
This involves copying data to new schema-defined event-instance 
table rows so genlog support logs them as well.
(4) Logging event struct or class instances that hold parameters 
of bde method/function/action calls to provide additional 
debug support.