ACD backwards compatibility

[Peter Ernst]

Dear Emboss developers,

  version: pre-release of EMBOSS-2.8.0.
  problem: ACD backwards compatibility

I realised that the upcoming EMBOSS release does not understand the
old attributes anymore (here: attribute "required"). Wouldn't it be
nice to have some backwards compatibility for the cases, where the
keywords simply have changed?

Otherwise authors of EMBASSY programs have to provide different
versions of ACD files for pre-2.8.0 and post-2.8.0 releases.

The command-line option "-debug" could issue a warning, however this
shouldn't be the default, because of the reason mentioned in the
paragraph before.

Example:

ACD: from graphtest.acd:

     xygraph: graph [
       prompt: "Graph type (? for list of types)"
       help: "Graphics device"
       parameter: "Y"
       required: "Y"
     ]


With pre-release 2.8.0:

 % graphtest
Error: File t/graphtest.acd line 6: (graph) Attribute 'required' unknown

 % acdvalid graphtest
Error: File t/graphtest.acd line 6: (graph) Attribute 'required' unknown


With release 2.7.1:

 % .../emboss-2.7.1/bin/acdvalid graphtest
Error: File t/graphtest.acd line 6: Multiple definition of
parameter/required/optional
Error: File t/graphtest.acd line 6: prompt specified but no information
Error: File t/graphtest.acd line 6: Unexpected information value for type
'xygraph'


I this simple example, I could solve the problem by simply removing
the "required" attribute, because the "parameter" attribute is still
there, but I think this is a general question.

Kind regards,

     Peter