The unstable/debug library has lots of useful functions like this: http://docs.racket-lang.org/unstable/Debugging.html
I use stuff like this when I'm debugging. I also put my own custom information in continuation marks and extract it later to learn more about the context. NB. My mark parameter library provides a nice layer atop cmarks for this: http://docs.racket-lang.org/unstable/Mark_Parameters.html Jay 2011/3/2 Matthias Felleisen <[email protected]>: > > 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 > > -- 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
