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 <[email protected]> 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/[email protected]/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! >
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