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clarify define-extended-language example

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This commit is contained in:
Burke Fetscher 2012-08-01 10:09:45 -05:00
parent 2032aaf341
commit db437e0ba8
1 changed files with 6 additions and 6 deletions
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12
collects/redex/scribblings/ref.scrbl
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@ -657,15 +657,15 @@ extended non-terminals. For example, this language:
(define-extended-language lc-num-lang (define-extended-language lc-num-lang
lc-lang lc-lang
(v .... (code:comment "extend the previous `v' non-terminal") (v .... (code:comment "extend the previous `v' non-terminal")
+ number
number) +)
(x (variable-except λ +))) (x (variable-except λ +)))
] ]
extends lc-lang with two new alternatives for the @racket[v] extends lc-lang with two new alternatives (@racket[+] and @racket[number])
non-terminal, carries forward the @racket[e] and @racket[c] for the @racket[v] non-terminal, carries forward the @racket[e]
non-terminals, and replaces the @racket[x] non-terminal with a and @racket[c] non-terminals, and replaces the @racket[x] non-terminal
new one (which happens to be equivalent to the one that would with a new one (which happens to be equivalent to the one that would
have been inherited). have been inherited).
The four-period ellipses indicates that the new language's The four-period ellipses indicates that the new language's