John Machin wrote:
Jeff Shannon wrote:
[...] If each record is CRLF terminated, then
you can get one record at a time simply by iterating over the file
("for line in open('myfile.dat'): ..."). You can have a dictionary
classes or factory functions, one for each record type, keyed off
of the 2-character identifier. Each class/factory would know the layout of that record type,
This is plausible only under the condition that Santa Claus is paying you $X per class/factory or per line of code, or you are so speed-crazy that you are machine-generating C code for the factories.
I think that's overly pessimistic. I *was* presuming a case where the number of record types was fairly small, and the definitions of those records reasonably constant. For ~10 or fewer types whose spec doesn't change, hand-coding the conversion would probably be quicker and/or more straightforward than writing a spec-parser as you suggest.
If, on the other hand, there are many record types, and/or those record types are subject to changes in specification, then yes, it'd be better to parse the specs from some sort of data file.
The O.P. didn't mention anything either way about how dynamic the record specs are, nor the number of record types expected. I suspect that we're both assuming a case similar to our own personal experiences, which are different enough to lead to different preferred solutions. ;)
Jeff Shannon Technician/Programmer Credit International
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