[racket] specifying strings without escaping backslash

Thank you Eli that works perfectly. I'm really just playing around getting
back into Racket


On Thu, Dec 5, 2013 at 5:24 PM, Eli Barzilay <eli at barzilay.org> wrote:

> Yesterday, Laurent wrote:
> > Or better here: @values{C:\Users\Harry\SANSKRIT\GRETIL
> > ALL\adyappu.htm} to avoid the superfluous ~a operation.
>
> Using `values' is not a good idea since it works only if you don't use
> nested @s or newlines.  If these things are included, you'll end up
> with a form that is equivalent to (values x y z) and things will
> probably break in a confusing way.
>
>
> > I've just surprised myself testing @(...){...} and seeing that it
> > works: @(lambda(x)x){C:\Users\Harry\SANSKRIT\GRETIL ALL\adyappu.htm}
>
> That's intentional, and more than that, any form can be used including
> @-forms, which means that to write a function that takes in two blocks
> of text you can do something like this:
>
>     @(define ((foo . text1) . text2) ...stuff...)
>
>     @@foo{some text}{some more text}
>
> (This is a simplified example again, where you just get a single
> argument, but in the general case you'd have multiple inputs for both
> texts.)
>
>
> Yesterday, Harry Spier wrote:
> >
> > 2)
> > What am I doing wrong here.  -- everything :-)
> > I'm trying to change the command character from @ to #  so that I
> > can have raw strings containing both \ and @  looking at the racket
> > documentation here:
> > http://docs.racket-lang.org/scribble/reader-internals.html?q=at-exp#
> > %28def._%28%28lib._scribble%2Freader..rkt%29._make-at-readtable%29%29
> > [...]
>
> It's possible to do that, though you'll need to implement your own
> reader.  Not too hard, since the scribble/reader functionality can
> build the appropriate table, but two notes before you go that route:
>
> 1. Overriding "#" is a bad idea, since it has special meaning in
>    Racket code.  Some obvious examples that you'll lose are boolean
>    literals, vector literals, and the convention that "#<" is an
>    unreadable value -- a convention that can lead to copy/paste
>    surprises if broken.
>
> 2. If you want to include more free-form text, there's a reader
>    feature that allows you to use customized tokens:
>
>      @foo|{ some text including @s }|
>
>    to use nested forms, you'd need to use "|@".  If that's not enough,
>    then you can also include more things between the braces and the
>    bars:
>
>      @foo|==!!=={ even more free text, including @|s etc }==!!|
>
>
> Yesterday, Greg Hendershott wrote:
> > I have @~a{} in muscle memory because it's handy for a variety of
> > purposes, including as an alternative to format/printf.
> >
> >     #lang at-exp racket
> >
> >     (define x 1)
> >     (define y 10)
> >
> >     (format "x is ~a, y is ~a, and x + y is ~a" x y (+ x y))
> >     ;; or
> >     @~a{x is @x, y is @y, and x + y is @(+ x y)}
> >
> >     ;; both => "x is 1, y is 10, and x + y is 11"
>
> Allowing such things was very intentional in the design...  The
> `scribble/text' language goes further in that it allows many more
> things in the contents for printing.  There's no to-string form for it
> though, since I wasn't sure that it's a good idea -- mostly because
> people would be tempted to do something like
>
>     (display @to-string{stuff})
>
> where a long string gets allocated for no good reason.  Using `output'
> instead usually looks like this:
>
>     (output @list{
>       anything you want
>     })
>
> since lists are just scanned recursively by `output'.  As a side note,
> this use of lists makes some things very convenient -- instead of
> tricky code that uses `append-map' or `format's, `string-append's and
> `~a's, you just use lists, nesting them as much as you want.
>
>
> > p.s. I believe
> http://www.mail-archive.com/users@racket-lang.org/msg07162.html
> > predates `~a` being added to Racket.
>
> (It does.)
>
> --
>           ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
>                     http://barzilay.org/                   Maze is Life!
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.racket-lang.org/users/archive/attachments/20131205/890fa0d2/attachment.html>