* module/ice-9/exceptions.scm (guard): Add guard definition that
re-propagates from original continuation, runs consequents in tail
position in guard continuation, and doesn't rewind the stack.
* module/srfi/srfi-34.scm:
* module/rnrs/exceptions.scm (guard): Re-export from (ice-9
exceptions).
* module/ice-9/boot-9.scm (exception-kind, exception-args): Export.
* module/ice-9/exceptions.scm (exception-kind, exception-args):
Re-export.
* module/srfi/srfi-18.scm: Rewrite exception support in terms of core
exceptions, not SRFI-34/35.
* test-suite/tests/srfi-18.test: Since Guile doesn't expose the current
exception handler as such, SRFI-18 captures it using delimited
continuations. This means that we can't compare the result
of (current-exception-handler) with the installed handler using eq?,
even though the procedures are indeed equivalent. So, instead test
handler behavior.
* libguile/exceptions.c:
* libguile/exceptions.h: New files.
* libguile.h: Add exceptions.h.
* libguile/Makefile.am (libguile_@GUILE_EFFECTIVE_VERSION@_la_SOURCES):
(DOT_X_FILES, DOT_DOC_FILES, modinclude_HEADERS): Add exceptions.c and
exceptions.h.
* libguile/init.c (scm_i_init_guile): Initialize exceptions.
* libguile/threads.c (scm_spawn_thread): Use new names for
scm_i_make_catch_handler and scm_c_make_thunk.
* libguile/throw.c: Rewrite to be implemented in terms of
with-exception-handler / raise-exception.
* libguile/throw.h: Use data types from exceptions.h. Move
scm_report_stack_overflow and scm_report_out_of_memory to
exceptions.[ch].
* module/ice-9/boot-9.scm (&error, &programming-error)
(&non-continuable, make-exception-from-throw, raise-exception)
(with-exception-handler): New top-level definitions.
(throw, catch, with-throw-handler): Rewrite in terms of
with-exception-handler and raise-exception.
: New top-level definitions.
* module/ice-9/exceptions.scm: Adapt to re-export &error,
&programming-error, &non-continuable, raise-exception, and
with-exception-handler from boot-9.
(make-quit-exception, guile-quit-exception-converter): New exception
converters.
(make-exception-from-throw): Override core binding.
* test-suite/tests/eval.test ("inner trim with prompt tag"): Adapt to
"with-exception-handler" being the procedure on the stack.
("outer trim with prompt tag"): Likewise.
* test-suite/tests/exceptions.test (throw-test): Use pass-if-equal.
* module/srfi/srfi-34.scm: Reimplement in terms of core exceptions, and
make "guard" actually re-raise continuations with the original "raise"
continuation.
* module/ice-9/exceptions.scm: New file, derived from (rnrs
conditions). Perhaps unadvisedly, in this file I've renamed a number
of the identifiers. I have never found that the R6RS identifiers made
sense to me. For now this is an internal module that R6RS and SRFI-35
will be based on.
* module/Makefile.am (SOURCES): Add the new file.
* module/rnrs/conditions.scm (rnrs): Export renamed identifiers
from (ice-9 exceptions).
