[plt-scheme] is dynamic-require or namespace used here?

You could write a macro:

  (require/test (lib "RealLib.ss") (lib "MyLib.ss"))

that would ask which argument to expand to.

Robby

At Wed, 3 Sep 2003 19:57:37 -0400 (EDT), Ryan Jarvis wrote:
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> 
> I am browsing through the help desk trying to find a function that could
> be used here.  Imagine a program structured like this
> 
> (require (lib "RealLib.ss"))
> (require (lib "MyLib.ss"))
> 
> (uni-Do-This)
> (uni-Do-That)
> (uni-And-The-Other)
> 
> where RealLib and MyLib are basically identical libraries consisting of
> functions Do-This, Do-That, And-The-Other.
> 
> What I want to do is right when the program is executed it asks the user
> via read which library they want to use for the program.  If the user
> types RealLib then MzScheme/DrScheme would effectively compile the program
> as if the code were written like this
> 
> (require (prefix uni- (lib "RealLib.ss")))
> (require (lib "MyLib.ss"))
> 
> (uni-Do-This)
> (uni-Do-That)
> (uni-And-The-Other)
> 
> If the user typed in MyLib then the code would compile like this
> 
> (require (lib "RealLib.ss"))
> (require (prefix uni- (lib "MyLib.ss")))
> 
> (uni-Do-This)
> (uni-Do-That)
> (uni-And-The-Other)
> 
> I am looking at things like (dynamic-require) and namespaces
> but they are a bit hard to understand and I don't know if any of these are
> what I am looking for.  I thought namespace-require might work but I
> don't know how to get it to accept the words prefix and lib in the
> expression.  Or if all of this is even possible.
> 
> The explanation behind all of this is say I have a lib RealLib and I want
> to write my own version of the library with my own code, MyLib, but I want
> to keep all the procedure names the same.  In order to test if my library
> works, I would write a test program, write universal procedure calls and
> then dynamically call which library I want the procedures to load from
> *without changing the code in the test program* In other words, I can
> debug my library by first running the test program with the real library
> and then running it with my library to compare the output and I can do
> this without altering the code of the test program.
> 
> Thanks for any assistance.
> 
>