On Wed, 23 Mar 2005 06:21:30 +0100, Kay Schluehr <[EMAIL PROTECTED]>
wrote:
>I think my proposal was more in mind of Rons modified exec than
>Pythons lambda.
>
>When George proposed his unpacking behavoir for list-comps as a pack of
>suggar:
>
>1. [x*y-z for (x,y,z=0) in (1,2,3), (4,5), (6,7,8)]
>
>I interpreted it in a subsequent posting in lambda fashion:
>
>2. [(lambda x,y,z=0:x*y-z)(*v) for v in (1,2,3), (4,5), (6,7,8)]
Thank you Kay, All of this is really intersting and I'm learning a
lot about the language through these discussions.
The following is an experiment I did this morning. :-)
I was surprised it worked as well as it did, although I don't think it
should be used in any real production code. Not in it's present form
anyway.
The idea is to have a container class like a tuple for program code
that can be moved around and used when needed. Very flexable, maybe
if it could be done without the strings and the exec/eval() functions
in it?
Ron_Adam
# codedo.py
import types
class code(tuple):
"""
Inline Code Storage Class
name = code(('expression','expression',...))
varables = name.do([locals()],['invars'],'outvars')
This is experimental.
Warning: This is experimental! This class has not
been tested. It also uses exec, and eval(), which
can be a security risk.
"""
def do(self, *args ):
if type(args[0]) == type({}):
parentnames = args[0]
else:
parentnames = globals()
if len(args)>1:
argslist = args[1].split(',')
else:
argslist = args
for a in argslist:
if parentnames.has_key(a):
exec a+'=parentnames[a]'
for c in self:
exec(c)
return eval(args[-1]) # The last argument are the return
varable(s).
if __name__ == '__main__':
"""
Test it. This is only what works, not what doesn't.
"""
# Left to Right order.
y=3
print code(('y=y*2','x=y**2')).do('x')
# *** Define and use later! ***
mybutton_action = code(('z=y*2','x=z**2','result=x+2'))
y = 1
print mybutton_action.do('y','result')
y = 10
print mybutton_action.do('y','result')
y = 100
print mybutton_action.do('y','result')
# Return multiple values.
toxyz = code(('x*=2','y*=2','try:z\nexcept:z=0','z*=2'))
x = 2
y = 3
#z = 4
a, b, c = toxyz.do('x,y,z')
print a, b, c
# 1. [x*y-z for (x,y,z=0) in (1,2,3), (4,5), (6,7,8)]
print code(('r=[]','for x,y,z in
[(1,2,3),(4,5,0),(7,8,9)]:r.append(x*y-z)')).do('r')
# or... trailing comma needed here to make a uni-tuple.
print code(('r=list([x*y-z for x,y,z in
(1,2,3),(4,5,0),(7,8,9)])',)).do('r')
# post process list before returning.
print code(('r = [ x for x in range(1,11) ]','r=r*2')).do('r')
# From within a function:
# We need to pass locals() to so it can find the variables.
def fn1():
x = 5
y = 10
lfunction = code(('z = x*2+y',)).do(locals(),'x,y','z')
print lfunction
fn1()
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