Error message when "no decoder" should be clearer.

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Write a specification with missing "pretty" exported functions
2. run demo application

What is the expected output? What do you see instead?
See: "GDSL modules contain no decoder function"
Would like to see: "GDSL module is missing decoder function pretty : (insndata) 
-> rope"

What version of the product are you using? On what operating system?
git master
linux

Please provide any additional information below.
Not a critical issue as most people won't be writing new decoders, but it would 
have saved me a lot of time searching for the answer.

Original issue reported on code.google.com by [email protected] on 31 Jul 2014 at 3:46

[GoogleCodeExporter]

Original comment by [email protected] on 9 Sep 2014 at 4:31

• Changed state: Accepted