PEP 308: "then" "else" for deprecating "and" "or" side effects

François Pinard pinard at
Fri Feb 14 18:57:33 CET 2003

[Carel Fellinger]

> Does that little language of yours have an if-else statement?

No, sorry.  This is not an imperative language.  The `... when ... else' is
the closest we have to an imperative `if else'.

Let me chat a bit.  We use the little language to describe fairly complex
relations of prerequisites for a selection and matching subsystem -- and no,
not at all, we are not in the sex industry!  :-).  The data gets compiled
into forms, which are then quite optimised for efficient evaluation.

The language, optimiser and evaluator have all been implemented in Python.
The legibility and cleanness of Python, also helped with our little
language, allowed such a clear expression of the problem that it was easy to
add new optimisations, unthought with the previous implementations in PL/I
or C.  The current setup even compares favourably speed-wise, wiping out
most doubts and concerns of old-timers, here.  The net effect is an
administrative decision that all projects are likely to be developed in
Python, from now on.  Surely very pleasurable for me! :-)

François Pinard

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