Ok, but why is "cond" defined to behave differently? I expected "cond" to behave the same as "if".
Justin On Mar 16, 2014 4:59 PM, "Jens Axel Søgaard" <jensa...@soegaard.net> wrote: > The problem is that begin does not introduce a new scope. > You can use (let () ...) or block instead. > > > http://docs.racket-lang.org/reference/block.html?q=block#%28form._%28%28lib._racket%2Fblock..rkt%29._block%29%29 > > /soegaard > > > 2014-03-16 21:38 GMT+01:00 Justin Zamora <jus...@zamora.com>: > > What is the reason for not allowing internal definitions in the "then" > and > > "else" parts of an "if"? > > > > This fails with "define: not allowed in an expression context": > > (if (< 3 4) > > 5 > > (begin > > (define a 7) > > a)) > > > > But the equivalent "cond" works fine: > > (cond > > [(< 3 4) 5] > > [else (define a 7) > > a]) > > > > I notice that the expansion of "cond" encloses the clauses inside > > (let-values () ...). Why doesn't "if" allow this? > > > > Justin > > > > ____________________ > > Racket Users list: > > http://lists.racket-lang.org/users > > > > > > -- > -- > Jens Axel Søgaard >
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