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comp.lang.lisp

Re: Lisp newbie, data structures, parsing.

William James

10/1/2015 3:40:00 PM

Rob Warnock wrote:

> where if "form2" is omitted then the variable "var" still *is* updated
> every time through the loop, but by the value of "form1", which is
> re-evaluated every time though the loop. That's why the common idiom
> for stepping through the lines of a file is this:
>
> (with-open-file (s "filename")
> (loop for line = (read-line s nil nil)
> while line
> do (process-one-line line)))
>
> instead of this:
>
> (with-open-file (s "filename")
> (loop for line = (read-line s nil nil) then (read-line s nil nil)
> while line
> do (process-one-line line)))

Gauche Scheme:

(with-input-from-file "filename"
(lambda () (generator-for-each process-one-line read-line)))

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