The Guile REPL code (in system/repl/repl.scm and related files)
uses a catch
with a pre-unwind handler to capture the stack when
an error occurs in an expression that was typed into the REPL, and debug
that stack interactively in the context of the error.
These procedures are available for use by user programs, in the
(system repl error-handling)
module.
(use-modules (system repl error-handling))
Call a thunk in a context in which errors are handled.
Note that this function was written when throw
/catch
were
the fundamental exception handling primitives in Guile, and so exposes
some aspects of that interface (notably in the form of the procedural
handlers). Guile will probably replace this function with a
call-with-standard-exception-handling
in the future.
There are five keyword arguments:
Specifies what to do before the stack is unwound.
Valid options are debug
(the default), which will enter a
debugger; pass
, in which case nothing is done, and the exception
is rethrown; or a procedure, which will be the pre-unwind handler.
Specifies what to do after the stack is unwound.
Valid options are catch
(the default), which will silently catch
errors, returning the unspecified value; report
, which prints out
a description of the error (via display-error
), and then returns
the unspecified value; or a procedure, which will be the catch handler.
Specifies a trap handler: what to do when a breakpoint is hit.
Valid options are debug
, which will enter the debugger;
pass
, which does nothing; or disabled
, which disables
traps entirely. See Traps, for more information.
A set of keys to ignore, as a list.
A set of keys to always report even if the post-error handler is
catch
, as a list.