You are correct that it is effectively black magic, in that you probably
don't need to know about it right now. Only a small percentage of
Racket programmers will ever need to know about it.
When you look at the "reference/symbols.html" page of Racket
documentation, pretend that you don't see
(gensym) generates something that cannot be created again in anyway.
Even it is printed as 'g1753, that doesn't mean typing 'g1753 will get
the same thing, nor that (string->symbol "g1753") will either. This is
the whole point of (gensym).
The Web server (basicaly) runs symbol->string to create t
That sounds like a black magic. I am almost tempted to ask how it's done.
I imagined (gensym) would generate some unique sequence not used so
far. Why would this approach not work?
2011/7/31 Jay McCarthy :
> Gensym produces symbols that are not eq to any other symbols created any
> other way. Th
While trying to scribble some documentation, I came across what seems to be
a bug involving contracts and scribble's interaction form.
my-module.scrbl:
#lang scribble/manual
@(require scribble/eval)
When I introduce contracts into "my-module.rkt", the following lines...
@(define my-eval (make-e
Gensym produces symbols that are not eq to any other symbols created any other
way. The bindings library produces symbols from strings, so they aren't eq to
the gensym'd one.
Jay
Sent from my iPhone
On 2011/07/31, at 15:13, J G Cho wrote:
> I am a bit puzzled by this error:
>
>
> Exceptio
I am a bit puzzled by this error:
Exception
The application raised an exception with the message:
extract-binding/single: 'q10493 not found in '((q10493 . "no"))
Context:
Symbol q10493 was generated by (gensym 'q) and used in
(list (radio-input (symbol->string nom) "yes")
(ra
I think you want `find-seconds', which doesn't need a week day or year
day.
At Sun, 31 Jul 2011 11:47:13 +0100 (BST), Mark Carter wrote:
> I'm trying to do a calculation which requires converting a date into years.
>
> Converting a date into seconds is OK, too.
>
> The problem is, there doesn't
I'm trying to do a calculation which requires converting a date into years.
Converting a date into seconds is OK, too.
The problem is, there doesn't seem to be a good way of doing this in Racket.
There is a date->seconds function, which looks useful. However, the make-date
function takes in a
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