SEwPR PLT Redex code error? (pg 225)

[Andrew Kent]

A student today pointed out the standard reduction definition for ISWIM on pg 225 in SEwPR is broken:

#lang racket
(require redex)

;; iswim
;; definition from pg 217
(define-language iswim
((M N L K) X (λ X M) (M M) b (o2 M M) (o1 M))
(o o1 o2)
(o1 add1 sub1 iszero)
(o2 + - *)
(b number)
((V U W) b X (λ X M))
(E hole (V E) (E M) (o V ... E M ...))
(X Y Z variable-not-otherwise-mentioned))

(define-metafunction iswim
subst : any ... -> any)

;; iswim-standard
;; definition from pg 225
(define iswim-standard
(reduction-relation
iswim
(v ((λ X M) V) (subst M X V) vω)
(v (o b ...) (δ (o b ...)) δ)
with
[(--> (in-hole E M) (in-hole E N)) (v M N)]))


Error message: "reduction-relation: shortcut name may not be a non-terminal in: M"

Only posting this here since I couldn't find anything about it on the errata.

Have a good day!

Best,
Andrew

[Matthias Felleisen]

This is must be a regression. The build-process for the second part includes running the figures (and their tests).

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[Robby Findler]

This is a backwards incompatibility that we discussed on this very
mailing list, actually. The syntax error message I believe pinpoints
the change that needs to be made to the model -- simply renaming the
variables M and N should do the trick.

Sorry for the inconvenience.

Robby

[Sam Caldwell]

I am pretty sure it is a result of this change:

https://groups.google.com/d/topic/racket-users/blV3EEkJxVk/discussion

[Matthias Felleisen]

My fault!