Switch branches/tags
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
142 lines (133 sloc) 6.48 KB
Accumulation of half-understood design decisions eventually
chokes a program as a water weed chokes a canal. By refactoring
you can ensure that your full understanding of how the program
should be designed is always reflected in the program. As a
water weed quickly spreads its tendrils, partially understood
design decisions quickly spread their effects throughout your
program. No one or two or even ten individual actions will be
enough to eradicate the problem.
-- Martin Fowler, _Refactoring: Improving the Design
of Existing Code_, p. 360
some things that I'd like to do in 0.6.x, in no particular order:
The batch-related command line options for SBCL don't work
A small part of making them work properly is making sure that
verbose GC messages end up piped to error output.
Make sure that when the system dies due to an unhandled error
in batch mode, the error is printed successfully, whether
FINISH-OUTPUT or an extra newline or whatever is required.
Make sure that dies gracefully when one of the SBCLs
it's running dies with an error.
Actually, the ANSI *DEBUGGER-HOOK* variable might be a better
place to put the die-on-unhandled-error functionality.
As long as I'm working on the batch-related command-line options,
it would be reasonable to add one more option to "do what I'd want",
testing standard input for non-TTY-ness and running in no-programmer
mode if so.
?? Do it.
In order to make a well-behaved backtrace when a batch program
terminates abnormally, it should be limited in length.
?? Add a *DEBUG-BACKTRACE-COUNT* variable, initially set to 64,
to provide a default for the COUNT argument to BACKTRACE.
I used CMU CL for years, and dozens of times I cursed the
inadequate breakpoint-based TRACE facility which doesn't work on
some functions, and I never realized that there's a wrapper-based
facility too until I was wading through the source code for SBCL.
Yes, I know I should have RTFM, but there is a lot of M..
(By the way, it would also be nice to have tracing behave
better with generic functions. TRACEing a generic function probably
shouldn't prevent DEFMETHOD from being used to redefine its
methods, and should perhaps trace each of its methods as well
as the generic function itself.)
?? possibility 1: Add error-handling code in ntrace.lisp to
catch failure to set breakpoints and retry using
wrapper-based tracing.
?? possibility 2: Add error-handling code in ntrace.lisp to
catch failure to catch failure to set breakpoints and output
a message suggesting retrying with wrapper-based breakpoints
?? possibility 3: Fix the breakpoint-based TRACE facility so that
it always works.
My system of parallel build directories seems to add
complexity without adding value.
?? Replace it with a system where fasl output files live in the
same directories as the sources and have names a la
"foo.fasl-from-host and "foo.fasl-from-xc".
?? (Perhaps something else will be required in order to port
to Microsoft Windows, since its filesystem doesn't have
symbolic links.)
It might be good to use the syntax (DEBUGGER-SPECIAL *PRINT-LEVEL*)
etc. to control the in-the-debug-context special variables. Then we
wouldn't have to pick and choose which variables we shadow in the
The shadowing values could also be made persistent between
debugger invocations, so that entering the debugger, doing
(SETF *PRINT-LEVEL* 2), and exiting the debugger would leave
(DEBUGGER-SPECIAL *PRINT-LEVEL*) set to 2, and upon reentry to the
debugger, *PRINT-LEVEL* would be set back to 2.
The :SB-TEST target feature should do something.
I still haven't cleaned up the cut-and-paste programming in
We be able to get rid of the IR1 interpreter, which would
not only get rid of all the code in *eval*.lisp, but also allow us to
reduce the number of special cases elsewhere in the system. (Try
grepping for 'interpret' sometime.:-) Making this usable might
require cleaning up %DEFSTRUCT, %DEFUN, etc. to use EVAL-WHEN
instead of IR1 transform magic, which would be a good
thing in itself, but might be a fair amount of work.)
?? Delete, delete, delete.
other known issues with no particular target date:
bugs listed on the man page
more regression tests
byte compilation of appropriate parts of the system, so that the
system core isn't so big
Search for unused external symbols (ones which are not bound, fbound,
types, or whatever, and also have no other uses as e.g. flags) and
delete them. This should make the system core a little smaller, but
is mostly useful just to make the source code smaller and simpler.
adding new FOPs to provide something like CMU CL's FOP-SYMBOL-SAVE and
FOP-SMALL-SYMBOL-SAVE functionality, so that fasl files will be more
compact. (FOP-SYMBOL-SAVE used *PACKAGE*, which was concise but allowed
obscure bugs. Something like FOP-LAST-PACKAGE-SYMBOL-SAVE could have
much of the same conciseness advantage without the bugs.)
hundreds of FIXME notes in the sources from WHN
various other unfinished business from CMU CL and before, marked with
"XX" or "XXX" or "###" or "***" or "???" or "pfw" or "@@@@" or "zzzzz"
or probably also other codes that I haven't noticed or have forgotten.
(Things marked as KLUDGE are in general things which are ugly or
confusing, but that, for whatever reason, may stay that way