Re: Data table text I/O package?

[Preben Randhol <randhol+cla@pvv.org>]

On Wed, Jun 15, 2005 at 05:02:37PM +0200, Jacob Sparre Andersen wrote:
> Preben Randhol wrote:
> > Jacob Sparre Andersen <sparre@nbi.dk> wrote on 15/06/2005 (13:38) :
> 
> > > The important part is to have the checking of the headers and the
> > > generation of Put_Line and Get_Line procedures automated based on
> > > a record type (and not too much more).  Since I need records (for
> > > type checking) and not just simple arrays, I can't manage with a
> > > generic package, but have to put some code generation into the
> > > system (or can I play some tricks with streams?).
> > 
> > So the header might be:
> > 
> > Integer   Float   Text
> 
> Not quite.  The headers would be field names, not just types.  I.e.:
> 
> Gene ID p-value Expression-level        Description     Human cromosome
> GE29031 0.04539 245.45  Cyclin-B1       17
> 
> > and the data could be:
> > 
> > 1         0.9     Start point
> > 2         0.3     Minimum
> > 3         6.0     End point
> > 
> > and then you want to check the data and validate that they are of
> > the correct type as indicated by the header? To generate the header
> > you want that the package finds out which type a certain data type
> > is and output this type in the header?
> 
> Sort of.  Except that I would use the names of the fields in the
> record and not just the types of the fields.
> 
> One of my problems is that I have different kinds of files (in terms
> of meaning of the numbers) where the types for all practical purposes
> are the same.

So you have different files with for example p-value, and in all the
p-value is a float?

If so, then I would have made a map something like:

   Gene              => "Text"
   ID                => "Float"
   p-value           => "My_Float"  (In case you have a special type) 
   Expression-level  => "Text"
   Description       => "Text"
   Human cromosome   => "Text"
   ...
   

   and when you read in the values you can do a 

   Is_Valid_Type (Column_Type : String; Value : String) return Boolean
   is
   begin
      if Column_Type = "Float" then
         declare
            F : Float := Float'Value (Value);
         begin
            return true;
         exception
            when => others
               return false;
         end;
      elsif Column_Type = "Integer" then
      ...

-- 
Preben Randhol -------------- http://www.pvv.org/~randhol/Ada95 --
"Have another drink, not-Corporal Nobby?" said Sergeant Colon unsteadily.
"I do not mind if I do, not-Sgt Colon," said Nobby.
        -- The joys of working undercover
                   (Terry Pratchett, Guards! Guards!)