Compiler directives in the source

[A. Lloyd Flanagan]

Dale Strickland-Clark <dale at riverhall.NOTHANKS.co.uk> wrote in message news:<u4g24vs1ah54s0sqnbjc1o1c6bds3u6rm5 at 4ax.com>...
> The earlier discussion on coding directives in comments got me
> thinking.
> 
> 
> I think the following compiler options would be usefully avilable as
> directives in the source as well as on the command line:
> 
> -O     : optimize generated bytecode 
> -OO    : remove doc-strings in addition to the -O optimizations
> -Q arg : division options:
> -S     : don't imply 'import site' on initialization
> -v     : verbose (trace import statements) (also PYTHONVERBOSE=x)
> -W arg : warning control 
> -x     : skip first line of source
> 
> To that list, I would like to add:
> 
> debug arg : control value of __debug__ and assert() (independent of
>             optimisation)
...
> That would give us a set of compiler directives like these:
> 
> %optimize off | on | full
> %division old | warn |new
> %importsite off | on
> %verbose off | on
> %warnings arg
> %skip 1
> %debug off | on
> %ignorecase off | on     (like PYTHONCASEOK)
> %path dir;dir...         (like PYTHONPATH)
> %home dir                (like PYTHONHOME)
> 

FWIW, I like the idea for setting global options for the file (much
better than magic comments).  I don't like the idea for things like
'conditional compilation' or skipping lines; that to me just adds a
new complexity on top of existing features.  If people start using
these directives like the compiler directives in C, we'll have the
same problems with them that C has.

I'd also suggest they be required to be placed before any code in the
file; since they're meta-directives they shouldn't get mixed with
code, again for readability.