Metacircular evaluator of Scheme in Dr. Racket

Question

When I am trying to run an evaluator in Dr. Racket, it shows the error: 'Module Language: there can only be one expression in the definitions window'.

Obviously there are multiple definitions in this window, an evaluator has multiple definitions, so how can I run these multiple definitions ? or is there any other method to run the evaluators.

Any help would be appreciated.

Try to add `#lang racket` as the first line in the definitions window. — uselpa, Oct 30 '13 at 07:18
@uselpa even that is not working, set-car! is unknown to #lang racket. set-car!: unbound identifier in module in: set-car! — Hari Chaudhary, Oct 30 '13 at 08:43
For set-car! see http://stackoverflow.com/questions/9475366/set-car-set-cdr-unbound-in-racket. You could also try `#!r6rs` instead of `#lang racket`. — uselpa, Oct 30 '13 at 09:37
So you have "#lang scheme "on the first line? Try "#lang planet neil/sicp" if your code has to do with SICP. Otherwise you might need #!r5rs or #!r6rs as first line. You can also choose a language in the menu. I — Sylwester, Oct 30 '13 at 09:38
@uselpa , #lang r5rs works, but again I got stuck in 'error'. But resolved this by: '#lang r5rs (#%require (only scheme/base error))'. Thanks — Hari Chaudhary, Oct 30 '13 at 09:44

score 6 · Answer 1 · edited Feb 26 '14 at 21:25

6

I am new to Racket, and when I was trying to run my very first program I too encountered this error.

I added #lang racket/base at the beginning of the source code and it solved this problem.

edited Feb 26 '14 at 21:25

Will Ness

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answered Feb 26 '14 at 18:39

ancab

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score 1 · Accepted Answer · answered Oct 30 '13 at 09:48

1

#lang r5rs

resolve set-car! problem, but error was unknown this time. I resolved this by (#%require (only scheme/base error)).

So I add these two lines to make my evaluator run:

#lang r5rs
(#%require (only scheme/base error))

answered Oct 30 '13 at 09:48

Hari Chaudhary

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Metacircular evaluator of Scheme in Dr. Racket

2 Answers2