<div dir="ltr">Thank you Eli that works perfectly. I'm really just playing around getting back into Racket </div><div class="gmail_extra"> <div class="gmail_quote">On Thu, Dec 5, 2013 at 5:24 PM, Eli Barzilay <<a href="mailto:eli@barzilay.org" target="_blank">eli@barzilay.org</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Yesterday, Laurent wrote: > Or better here: @values{C:\Users\Harry\SANSKRIT\GRETIL <div class="im">> ALL\adyappu.htm} to avoid the superfluous ~a operation. </div>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. <div class="im"> > I've just surprised myself testing @(...){...} and seeing that it </div>> 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.) <div class="im"> 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: > <a href="http://docs.racket-lang.org/scribble/reader-internals.html?q=at-exp#" target="_blank">http://docs.racket-lang.org/scribble/reader-internals.html?q=at-exp#</a> > %28def._%28%28lib._scribble%2Freader..rkt%29._make-at-readtable%29%29 </div>> [...] 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 }==!!| <div class="im"> 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" </div>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. <div class="im"> > p.s. I believe <a href="http://www.mail-archive.com/users@racket-lang.org/msg07162.html" target="_blank">http://www.mail-archive.com/users@racket-lang.org/msg07162.html</a> > predates `~a` being added to Racket. </div>(It does.) -- ((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay: <a href="http://barzilay.org/" target="_blank">http://barzilay.org/</a> Maze is Life! </blockquote></div> </div>