The `load` function can load a module declaration, but it doesn't
instantiate the module.
In other words, using `load` is like
```
> (module m racket/base
(define (neq . args) (not (apply = args)))
(provide neq))
> (neq 1 0)
neq: undefined;
cannot reference an identifier before its definition
in module: 'program
```
But `require` loads the module, instantiates it, and imports the
module's `provide`s, so using `require` on a file is analogous to
```
> (module m racket/base
(define (neq . args) (not (apply = args)))
(provide neq))
> (require 'm)
> (neq 1 0)
#t
```
As you observe, `racket` doesn't track changes to files, and `require`
doesn't re-load a module that it has previously loaded (even if the
module's source changed).
You might want to try a tool like `xrepl`, which supports re-loading
changed modules:
http://docs.racket-lang.org/xrepl/index.html
At Thu, 7 May 2015 22:02:38 -0700 (PDT), Thomas Lynch wrote:
> Her is a small pointless program
>
> #lang racket
> (define (neq args) (not (apply = args)))
> (provide neq)
>
> So then loading this in racket:
>
> racket@> (load "temp-lib.rkt")
> racket@> (neq 1 0)
> neq: undefined;
> cannot reference undefined identifier
> context...:
> /usr/share/racket/collects/racket/private/misc.rkt:87:7
>
>
> Why is neq undefined after the load? I could see symbols in a module with
> load before the upgrade ..
>
> Now there is a (provide neq) in there so why not use require? Lets try
> that in the same session:
>
> racket@> (require "temp-lib.rkt")
> racket@> (neq 1 0)
> neq: arity mismatch;
> the expected number of arguments does not match the given number
> expected: 1
> given: 2
> arguments...:
> 1
> 0
> context...:
> /usr/share/racket/collects/racket/private/misc.rkt:87:7
>
>
> Yes, now the symbol can be seen. Good, and oh yeah, a '.'is missing in the
> source so let me add that. The edited and saved source code now appears as:
>
> #lang racket
> (define (neq . args) (not (apply = args)))
> (provide neq)
>
>
> So again, in the same session, lets use this new better source code:
>
> racket@> (neq 1 0)
> neq: arity mismatch;
> the expected number of arguments does not match the given number
> expected: 1
> given: 2
> arguments...:
> 1
> 0
> context...:
> /usr/share/racket/collects/racket/private/misc.rkt:87:7
>
>
> Alas, racket does seem to see the updated code. My guess is that the
> second require did nothing because racket already though it had that file.
> Is this the case? Anyway, I did this twice in different variations, and
> indeed new edits do not come in. Well then what to do, here I kill the
> racket process and run it again (kinda like rebooting windows after a
> problem):
>
> racket@>
> It's been nice interacting with you!
> Press C-c C-z to bring me back.
> Welcome to Racket v6.1.
> racket@> (require "temp-lib.rkt")
> racket@> (neq 1 0)
> #t
> racket@>
> racket@> (require "temp-lib.rkt")
> racket@> (neq 1 0)
> #t
> racket@>
>
>
> Yes, after rebooting racket I see my changes.
>
> Ok, what is going on here? What happened to load? How do I load a file so
> that I can work on it while seeing all the bindings? How do I reload a
> file after an edit?
>
>
>
>
>
> --
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```
Output:
```
program:40:57: read: illegal use of `.'
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