Variable scope and caller

[Dennis Lee Bieber]

Ben Leslie fed this fish to the penguins on Sunday 15 December 2002 
08:54 pm:


> a = inspect.currentframe().f_back.f_locals

        Ah, the missing piece. And an optimization from the loops.

import inspect

class pstring:
    def __init__(self, fstring):
        self.format = fstring

    def __str__(self):
        inscope = {}
	inscope.update(globals())
	inscope.update(inspect.currentframe().f_back.f_locals)
        return self.format % inscope

def aCaller():
    y = "Dennis"
    x = pstring("Who's %(y)s")
    print x
    y = "me"
    print x
    

y = "erik"
z = "world"
x = pstring("Hello %(y)s")
g = pstring("Goodbye %(z)s")

print x
aCaller()
print x, g
y = "Wulfraed"
print x
print g


gives

Hello erik
Who's Dennis
Who's me
Hello erik Goodbye world
Hello Wulfraed
Goodbye world


        Of course, I do see a flaw, the solution of which will be left as an 
exercise for the student...

        Namely, this only goes back ONE level of scope; I suspect one needs to 
iterate on the frame stack to get to the bottom (top?) and then work 
down to the current frame if one really wants to catch any version of 
the named variable (rather than Python's Global and Local [one frame 
up] system)

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