Module Core_kernel.Debug

Utilities for printing debug messages.

val eprint : Base.String.t -> Base.Unit.t

eprint message prints to stderr message, followed by a newline and flush. This is the same as prerr_endline.

val eprints : Base.String.t -> 'a -> ('a -> Sexp.t) -> Base.Unit.t

eprints message a sexp_of_a prints to stderr message and a as a sexp, followed by a newline and flush.

val eprint_s : Sexp.t -> Base.Unit.t

eprint_s sexp prints sexp to stderr, followed by a newline and a flush.

val eprintf : ('rBase.Unit.tBase.String.tBase.Unit.t) format4 -> 'r

eprintf message arg1 ... argn prints to stderr message, with sprintf-style format characters instantiated, followed by a newline and flush.

module Make () : sig ... end

Debug.Make produces a debug function used to wrap a function to display arguments before calling and display results after returning. Intended usage is:

am, ams, and amf output a source code position and backtrace to stderr. amf accepts a printf-style format string. ams accepts a message, value, and sexp converter for that value. Typical usage looks like:

  ...;
Debug.am [%here];
  ...;
  Debug.amf [%here] "hello (%s, %s)" (X.to_string x) (Y.to_string y);
  ...;
  Debug.ams [%here] "hello" (x, y) <:sexp_of< X.t * Y.t >>;
  ...;

The am* functions output source code positions in the standard format "FILE:LINE:COL", which means that one can use a tool like emacs grep-mode on a buffer containing debug messages to step through one's code by stepping through the messages.

val ams : Source_code_position.t -> Base.String.t -> 'a -> ('a -> Sexp.t) -> Base.Unit.t
val should_print_backtrace : Base.Bool.t Base.Ref.t

should_print_backtrace governs whether the am* functions print a backtrace.