Automatic Code Generation

Ian Bicking ianb at colorstudy.com
Sun Oct 5 21:46:58 CEST 2003


On Sun, 2003-10-05 at 11:52, Rasmus Fogh wrote:
> Someone raised the question of automatic code generation a few weeks back.
> 
> And yes, we (CCPN) are using automatic Python code generation in a major
> way.  Basically we are making data models in UML, and using automatic code
> generation to make Python APIs, XML I/O etc. (more below). We can be found
> at http://www.ccpn.ac.uk/index.html
> 
> As a general point, automtic code generation would seem like a good idea
> in special cases where:
> 
> - a lot of repetitive code can be derived completely from a more compact
> or problem-oriented description.
> - The problem is large
> - You need to keep doing new pieces of code and/or maintain several sets
> of synchronized files on top of an evolving problem description
> - You avoid hand-modifying the code, either because you can get 100%
> automatic generation, or you can 'park' the handcoded modifications where
> they are read into the automatic generation process.

I would disagree that code generation is a good solution to these, or
nearly any case.  Specifically in Python, code generation isn't
necessary because you can build objects and classes dynamically.  So if
you have a non-Python representation of the object or class, you can
write code to dynamically create that class, instead of writing code
that writes code.

One possible exception to this may be templating languages, which
typically compile more directly to Python code, with the full generality
that entails.  But even in this circumstance I think there are
considerable arguments against compilation, as the compilation can be
difficult to manage and errors are not as well reported.  (But
unfortunately the alternative is an interpreted template, which has its
own issues)

Analogously I can imagine other situations where logic needs to be
embedded into the description, though even in those situations code
generation may not be necessary.

-- 
Ian Bicking | ianb at colorstudy.com | http://blog.ianbicking.org







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