Re: [xsl] Design approaches to separating "pure" code from "impure" code?

["G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>]

At 2011-05-19 09:45 -0400, Costello, Roger L. wrote:
> Hi Folks,
>
> This is a general design question.
>
> First, let me define some terms:
>
> I define "pure" code as code that doesn't do any I/O.
>
> I define "impure" code as code that does I/O.
>
> (Dimitre could probably provide better definitions of those terms)
>
> I am seeking your suggestions on ways to organize XSLT code to keep 
> pure code and impure code separate.

How about a "pure" (your definition) module has no match patterns 
(input) and no literal result elements (output)?

It is useful to create modules that have no match patterns or literal 
result elements, especially for re-use.  For example, generated text 
building or common calculations when doing publishing for multiple 
output formats.  When you keep the literal result elements out of the 
common code, you can re-use the common code regardless of the 
result.  Sounds obvious when written out, but I consciously will 
decide that a "common module" has only generated text and no literal 
result elements.

I hope this helps.

. . . . . . . . . . . . Ken

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