Thanks a lot, Matthew! That works!
On Tue, May 14, 2013 at 8:06 AM, Matthew Flatt <mfl...@cs.utah.edu> wrote: > Hi Alfred, > > See > > http://docs.racket-lang.org/guide/eval.html#(part._namespaces) > > Matthew > > At Tue, 14 May 2013 07:01:51 -0400, Alfred Zhong wrote: > > Hi Racket experts, > > > > I am reading SICP and trying this piece of code using Racke: > > > > (define (definition-value exp) > > (if (symbol? (cadr exp)) > > (caddr exp) > > (make-lambda > > (cdadr exp) ; formal parameters > > (cddr exp) ; body > > ) > > ) > > ) > > > > (define (make-lambda parameters body) > > (cons 'lambda (cons parameters body)) > > ) > > > > ( (eval (definition-value '(define (double x) (+ x x))) ) 10) > > > > In REPL, it return 20 with no problem. > > > > However, if I put it into a file and use racket command to run it (with > > #lang scheme in the file) > > > > it complains: > > compile: unbound identifier (and no #%app syntax transformer is bound) > at: > > lambda in: (lambda (x) (+ x x)) > > > > Do you have any idea what happened there? How can I solve this problem? > > > > Thanks, > > Alfred > > ____________________ > > Racket Users list: > > http://lists.racket-lang.org/users >
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