Python Trace Tables and ver 2 to ver 3 issue

Question

I found this code for printing a program trace and it works fine in Python2.

However, in Python 3 there are issues. I addressed the first one by replacing execfile(file_name) with exec(open(filename).read()), but now there is still an error of KeyError: 'do_setlocale'

I'm out of my depth here - I just want an easy way to trace variables in programs line by line - I like the way this program works and it would be great to get it working with Python 3. I even tried an online conversion program but got the same KeyError: 'do_setlocale'

Can anyone please help me to get it working?

import sys

if len(sys.argv) < 2:
        print __doc__
        exit()
else:
        file_name = sys.argv[1]

past_locals = {}
variable_list = []
table_content = ""

ignored_variables = set([
        'file_name',
        'trace',
        'sys',
        'past_locals',
        'variable_list',
        'table_content',
        'getattr',
        'name',
        'self',
        'object',
        'consumed',
        'data',
        'ignored_variables'])

def trace(frame, event, arg_unused):
        global past_locals, variable_list, table_content, ignored_variables
        relevant_locals = {}
        all_locals = frame.f_locals.copy()
        for k,v in all_locals.items():
                 if not k.startswith("__") and k not in ignored_variables:
                            relevant_locals[k] = v
        if len(relevant_locals) > 0 and past_locals != relevant_locals:
                 for i in relevant_locals:
                            if i not in past_locals:
                                     variable_list.append(i)
                 table_content += str(frame.f_lineno) + " || "
                 for variable in variable_list:
                            table_content += str(relevant_locals[variable]) + " | "
                 table_content = table_content[:-2]
                 table_content += '\n'
                 past_locals = relevant_locals
        return trace

sys.settrace(trace)

execfile(file_name)

table_header = "L || "
for variable in variable_list:
        table_header += variable + ' | '
table_header = table_header[:-2]
print table_header
print table_content

# python traceTable.py problem1.py

# problem1.py
a = 1
b = 2

a = a + b

Answer 1

That program has a couple of major flaws – for example, if the program being traced includes any functions with local variables, it will crash, even in Python 2.

Therefore, since I have nothing better to do, I wrote a program to do something like this called pytrace. It's written for Python 3.6, although it probably wouldn't take too long to make it work on lower versions if you need to.

Its output is a little different to your program's, but not massively so – the only thing that's missing is line numbers, which I imagine you could add in fairly easily (print frame.f_lineno at appropriate points). The rest is purely how the data are presented (your program stores all the output until the end so it can work out table headers, whereas mine prints everything as it goes).