Create a file 'debug.rkt' in your collects. It provides a single function:
;; tee : X Y -> Y (define (tee tag val) (displayln `(,tag ,val)) val) When you wish to debug, require debug,rkt and wrap questionable expressions with (tee 'whatdoesitdo some-xpr) On Mar 2, 2011, at 11:16 AM, Fred G. Martin wrote: > Thanks. > > I figured out how to put printf's into my core predicate, using begin > (followed by my predicate-expression). It turned out that the 3rd (of > the ca. 500) items in my hash table first exercised my error, so now > I'm on my way to fixing it. > > Is this what other people do? Is there a more elegant way? I guess > printf's are universal? > > Fred > > > On Wed, Mar 2, 2011 at 9:07 AM, Jay McCarthy <[email protected]> wrote: >> The backtrace does not include that information. However, the >> graphical debugger built in DrRacket will do what you'd like. Using it >> can be very time consuming though because it works by annotating your >> program and then running it with many more additional operations. Most >> of my students swear by it (although I have a hard time remembering to >> try it since it wasn't there when I started with Racket.) >> >> Jay >> >> 2011/3/2 Fred G. Martin <[email protected]>: >>> Hi all, >>> Is it possible to see the bindings of various things in a backtrace? I am >>> having trouble debugging my code because I'm not sure which input is causing >>> it to fail -- at some point, I'm trying to take the car of an empty list. >>> The outer thing is a for-each mapping over a hash table with about 500 >>> entries, and I'm not sure which entry is causing my inner stuff to break. >>> Can't use printf, right?... any advice? >>> thanks, >>> Fred >>> >>> >>> _________________________________________________ >>> For list-related administrative tasks: >>> http://lists.racket-lang.org/listinfo/users >>> >> >> >> >> -- >> Jay McCarthy <[email protected]> >> Assistant Professor / Brigham Young University >> http://faculty.cs.byu.edu/~jay >> >> "The glory of God is Intelligence" - D&C 93 >> > > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
