[plt-scheme] reading a whole file

From: Robby Findler (robby at cs.uchicago.edu)
Date: Mon Nov 10 00:33:15 EST 2008

Looks to me like it handles unicode just fine.


On Sun, Nov 9, 2008 at 11:05 PM, Shriram Krishnamurthi <sk at cs.brown.edu> wrote:
> Fast on the heels of this thread, today I had to insert a bunch of
> JavaScript gobbledygook into each of my HTML files.  Here's the Scheme
> code I wrote:
> ----------
> (define tracker "... gobbledygook goes here ...
> ")
> (define (go f)
>  (let ([txt (with-input-from-file f
>               (lambda () (read-string (file-size f))))])
>    (let ([new-txt
>           (regexp-replace (regexp "</HEAD>")
>                           txt
>                           (string-append tracker "</HEAD>"))])
>      (if (string=? txt new-txt)
>          (printf "Pattern not found in ~a~n" f)
>          (with-output-to-file "out"
>            (lambda () (write-string new-txt)))))))
> (go (vector-ref (current-command-line-arguments) 0))
> ----------
> [Orthogonal note: writing the gobbledygook was itself a bit painful,
> and made me better appreciate Python's quoting.]
> I then launched this from a `find' command in the shell that would
> locate the .html files, do a quick check relating "out" to the
> original, and then mv out to override original.
> I eyeballed the output to make sure there were no instances of
> "Pattern not found".  There was one, and I was able to cross-check why
> and make sure there was no problem.
> It sure would have been nice to make the above code both shorter and
> more robust with FILE->STRING and STRING->FILE...
> [This is really just a response to Richard, who seemed to be arguing
> against such primitives.  The "optics" argument is actually stood on
> its head here: my hand-written code is the 80...let's call it 60%
> solution, because it does no error-checking, probably doesn't handle
> Unicode, certainly doesn't care about automicity due to assumptions
> about myself, etc.  At any rate, given that this is *not* being used
> in a compositional manner, the 80% solution of reading the file into
> memory, processing it, and writing it back out seems to me just the
> right thing.  Counter-argument?]
> Shriram
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