[plt-scheme] suggestions and commendations for exercise 2.21

Matthias Felleisen wrote:

>
>
> I have modified convert-file so that it specifies where the file is 
> expected:
>
>> Welcome to DrScheme, version 206.1-cvs15mar2004.
>> Language: Beginning Student.
>> Teachpack: /Users/matthias/plt/teachpack/htdp/convert.ss.
>> > (convert-file "in.dat" f "out.dat")
>> convert-file: expected <name of existing file in 
>> /Users/matthias/plt/collects/htdp/Test/> as first argument, given: 
>> "in.dat"
>> > (convert-file "convert-in.dat" f "out.dat")
>
> ...
>
> Is this sufficiently helpful? -- Matthias
>
>
Yes, that would've helped me out quite a bit.

Most helpful would be the availibility of something like ifconfig mentioned

    (current-directory)

But I think the diagnostic error message is a very useful step in the 
right direction.