Thanks to all guileans who have responded. I seem to have a workable
solution based on Neil's code. The thing I hadn't grokked was the
existence of the with-input-from-string procedure. I had been messing
with defined? and symbol? but got nowhere.
FWIW the core bit of code I ended up with takes the name of a command,
<name> and looks for a string in a variable called Help-d-<name> if it
exists:
(set! help (string-append "Help-d-" name))
(let ((sym (with-input-from-string help read)))
(if (defined? sym)
(set! help (eval sym (current-module)))
(set! help "No help")
))
This seems to cover all the cases. I haven't really got to the bottom of
what that with-input-from-string procedure does - I got as far as the
documentation for read which mentions an s-expression. Elsewhere I have
seen references to "forms", perhaps there is something establishing some
basic terminology that I have missed...
But thanks a lot - I am on my way again...
Richard
