[Python-Dev] Pragmas: Just say "No!"

[Greg Ewing]

Greg Wilson <gvwilson@nevex.com>:

> Pragmas are a way to embed programs for the
> parser in the file being parsed.

I hope the BDFL has the good sense to run screaming from
anything that has the word "pragma" in it. As this discussion
demonstrates, it's far too fuzzy and open-ended a concept --
nobody can agree on what sort of thing a pragma is supposed
to be.

INTERVIEWER: Tell us how you came to be drawn into the
world of pragmas.

COMPILER WRITER: Well, it started off with little things. Just
a few boolean flags, a way to turn asserts on and off, debug output,
that sort of thing. I thought, what harm can it do? It's not like
I'm doing anything you couldn't do with command line switches,
right? Then it got a little bit heavier, integer values for
optimisation levels, even the odd string or two. Before I
knew it I was doing the real hard stuff, constant expressions,
conditionals, the whole shooting box. Then one day when I put
in a hook for making arbitrary calls into the interpreter, that
was when I finally realised I had a problem...

Greg Ewing, Computer Science Dept, +--------------------------------------+
University of Canterbury,	   | A citizen of NewZealandCorp, a	  |
Christchurch, New Zealand	   | wholly-owned subsidiary of USA Inc.  |
greg@cosc.canterbury.ac.nz	   +--------------------------------------+