@page
@node Debugging
@chapter Internal Debugging Interface

--- The name of this chapter needs to clearly distinguish it
    from the appendix describing the debugger UI.  The intro
    should have a pointer to the UI appendix.

@deffn primitive display-error stack port subr message args rest
Display an error message to the output port @var{port}.
@var{stack} is the saved stack for the error, @var{subr} is
the name of the procedure in which the error occured and
@var{message} is the actual error message, which may contain
formatting instructions. These will format the arguments in
the list @var{args} accordingly.  @var{rest} is currently
ignored.
@end deffn

@deffn primitive display-application frame [port [indent]]
Display a procedure application @var{frame} to the output port
@var{port}. @var{indent} specifies the indentation of the
output.
@end deffn

@deffn primitive display-backtrace stack port [first [depth]]
Display a backtrace to the output port @var{port}. @var{stack}
is the stack to take the backtrace from, @var{first} specifies
where in the stack to start and @var{depth} how much frames
to display. Both @var{first} and @var{depth} can be @code{#f},
which means that default values will be used.
@end deffn

@deffn primitive backtrace
Display a backtrace of the stack saved by the last error
to the current output port.
@end deffn

@deffn primitive malloc-stats
Return an alist ((@var{what} . @var{n}) ...) describing number
of malloced objects.
@var{what} is the second argument to @code{scm_must_malloc},
@var{n} is the number of objects of that type currently
allocated.
@end deffn

@deffn primitive debug-options-interface [setting]
Option interface for the debug options. Instead of using
this procedure directly, use the procedures @code{debug-enable},
@code{debug-disable}, @code{debug-set!} and @var{debug-options}.
@end deffn

@deffn primitive with-traps thunk
Call @var{thunk} with traps enabled.
@end deffn

@deffn primitive memoized? obj
Return @code{#t} if @var{obj} is memoized.
@end deffn

@deffn primitive unmemoize m
Unmemoize the memoized expression @var{m},
@end deffn

@deffn primitive memoized-environment m
Return the environment of the memoized expression @var{m}.
@end deffn

@deffn primitive procedure-name proc
Return the name of the procedure @var{proc}
@end deffn

@deffn primitive procedure-source proc
Return the source of the procedure @var{proc}.
@end deffn

@deffn primitive procedure-environment proc
Return the environment of the procedure @var{proc}.
@end deffn

@deffn primitive debug-object? obj
Return @code{#t} if @var{obj} is a debug object.
@end deffn

@deffn primitive frame-arguments frame
Return the arguments of @var{frame}.
@end deffn

@deffn primitive frame-evaluating-args? frame
Return @code{#t} if @var{frame} contains evaluated arguments.
@end deffn

@deffn primitive frame-next frame
Return the next frame of @var{frame}, or @code{#f} if
@var{frame} is the last frame in its stack.
@end deffn

@deffn primitive frame-number frame
Return the frame number of @var{frame}.
@end deffn

@deffn primitive frame-overflow? frame
Return @code{#t} if @var{frame} is an overflow frame.
@end deffn

@deffn primitive frame-previous frame
Return the previous frame of @var{frame}, or @code{#f} if
@var{frame} is the first frame in its stack.
@end deffn

@deffn primitive frame-procedure frame
Return the procedure for @var{frame}, or @code{#f} if no
procedure is associated with @var{frame}.
@end deffn

@deffn primitive frame-procedure? frame
Return @code{#t} if a procedure is associated with @var{frame}.
@end deffn

@deffn primitive frame-real? frame
Return @code{#t} if @var{frame} is a real frame.
@end deffn

@deffn primitive frame-source frame
Return the source of @var{frame}.
@end deffn

@deffn primitive frame? obj
Return @code{#t} if @var{obj} is a stack frame.
@end deffn

@deffn primitive last-stack-frame obj
Return a stack which consists of a single frame, which is the
last stack frame for @var{obj}. @var{obj} must be either a
debug object or a continuation.
@end deffn

@deffn primitive make-stack obj . args
Create a new stack. If @var{obj} is @code{#t}, the current
evaluation stack is used for creating the stack frames,
otherwise the frames are taken from @var{obj} (which must be
either a debug object or a continuation).

@var{args} should be a list containing any combination of
integer, procedure and @code{#t} values.

These values specify various ways of cutting away uninteresting
stack frames from the top and bottom of the stack that
@code{make-stack} returns.  They come in pairs like this:
@code{(@var{inner_cut_1} @var{outer_cut_1} @var{inner_cut_2}
@var{outer_cut_2} @dots{})}.

Each @var{inner_cut_N} can be @code{#t}, an integer, or a
procedure.  @code{#t} means to cut away all frames up to but
excluding the first user module frame.  An integer means to cut
away exactly that number of frames.  A procedure means to cut
away all frames up to but excluding the application frame whose
procedure matches the specified one.

Each @var{outer_cut_N} can be an integer or a procedure.  An
integer means to cut away that number of frames.  A procedure
means to cut away frames down to but excluding the application
frame whose procedure matches the specified one.

If the @var{outer_cut_N} of the last pair is missing, it is
taken as 0.
@end deffn

@deffn primitive stack-id stack
Return the identifier given to @var{stack} by @code{start-stack}.
@end deffn

@deffn primitive stack-length stack
Return the length of @var{stack}.
@end deffn

@deffn primitive stack-ref stack i
Return the @var{i}'th frame from @var{stack}.
@end deffn

@deffn primitive stack? obj
Return @code{#t} if @var{obj} is a calling stack.
@end deffn


@c Local Variables:
@c TeX-master: "guile.texi"
@c End: