On Mon, Apr 2, 2018 at 7:24 AM, David Foster <[email protected]> wrote:
> My understanding is that the Python interpreter already has enough
> information when bytecode-compiling a .py file to determine which names
> correspond to local variables in functions. That suggests it has enough
> information to identify all valid names in a .py file and in particular to
> identify which names are not valid.
>
It's not as simple as you think. Here's a demo. Using all of the
information available to the compiler, tell me which of these names
are valid and which are not:
import sys
def search_file(fn):
with open(fn) as f:
for line in f:
if "spam" in line and len(line) < 80:
print("Mmmm delicious spam")
if __name__ == "__main__":
try:
search_file(sys.argv[1])
except IndexError:
print("Please provide a file name", file=sys.stderr)
except FileNotFoundError:
print("File not found", file=sys.stderr)
except OSError as Exception:
print("Error %d reading file: %s" %
(Exception.errno, Exception.strerror))
except Exception:
print("Something else went wrong:")
import traceback
traceback.print_exc()
finally:
print("Goodbye.")
Okay. Reckon you got them all? Look again there's probably at least
one sneaky one that you missed. List them for me, and tell me what's
valid and what's not.
ChrisA
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