Scheme J-Bob/step examples w/ non-null focus paths return incorrect results; ACL2 equivalents return correctly.

[ghost]

I was going through the Recess section on J-Bob, starting on page 164, when I noticed that some of the Scheme examples in little-prover.scm give incorrect results when run in MITScheme/DrRacket, but their ACL2 equivalents in little-prover.lisp give correct results when run in ACL2/DrRacket. I ran the first five Chapter 1 examples in both MIT/GNU Scheme and Dr Racket using R5RS (as described in the README) - the REPL dialogue in both interpreters proceeded as follows:

$ (load "j-bob/scheme/j-bob-lang.scm")
$ (load "j-bob/scheme/j-bob.scm")
$ (load "j-bob/scheme/little-prover.scm")
$ (chapter1.example1) ;;
-> (car (cons 'ham '(eggs))) ;; INCORRECT; should be 'ham
$ (chapter1.example2)
-> 't ;; CORRECT
$ (chapter1.example3)
-> (atom (cons 'ham '(eggs))) ;; INCORRECT; should be 'nil
$ (chapter1.example4)
-> 'nil ;; CORRECT
$ (chapter1.example5)
-> (equal 'flapjack (atom (cons a b))) ;; INCORRECT; should be 'nil

I noticed that the correct and incorrect examples differ in one key respect: the correct examples have no path to the focus (i.e., the focus is the entire expression) in their definitions, whereas the incorrect examples have at least one step with a path to the focus. Here's the same Chapter 1 examples, run with the ACL2 Dracula package in Dr Racket, showing correct output for all examples:

$ (include-book "j-bob-lang" :dir :teachpacks)
$ (include-book "j-bob" :dir :teachpacks)
$ (include-book "little-prover" :dir :teachpacks)
$ (chapter1.example1)
-> 'ham ;; CORRECT
$ (chapter1.example2)
-> 't ;; CORRECT
$ (chapter1.example3)
-> 'nil ;; CORRECT
$ (chapter1.example4)
-> 'nil ;; CORRECT
$ (chapter1.example5)
-> 'nil ;; CORRECT

Diagnosing why this is occurring is beyond my abilities at this point - can one of the authors, or someone who is more well-versed in Scheme/LISP than I am, explain what's going on here?

[ghost]

Never mind, I foolishly neglected to update my repo - including commit 1f68e43 fixed this issue.

[carl-eastlund]

Glad to see the issue is fixed, sorry for the initial difficulties. Happy proving!