Comparing ASTs in Python to show that "elif" is desugared in the parser

gistfile1.txt

[1] fs-boone@zhenghe ~/classes/cs321/hw1 $ cat print-ast.py 
#!/usr/bin/env python
import sys, ast
print ast.dump(ast.parse(sys.stdin.read()))
[1] fs-boone@zhenghe ~/classes/cs321/hw1 $ cat test1
if x == 1:
    print 1
elif x == 2:
    print 3
else:
     print 'Something else'
[1] fs-boone@zhenghe ~/classes/cs321/hw1 $ cat test2
if x == 1:
    print 1
else:
    if x == 2:
         print 3
    else:
         print 'Something else'
[1] fs-boone@zhenghe ~/classes/cs321/hw1 $ ./print-ast.py < test1
Module(body=[If(test=Compare(left=Name(id='x', ctx=Load()), ops=[Eq()], comparators=[Num(n=1)]), body=[Print(dest=None, values=[Num(n=1)], nl=True)], orelse=[If(test=Compare(left=Name(id='x', ctx=Load()), ops=[Eq()], comparators=[Num(n=2)]), body=[Print(dest=None, values=[Num(n=3)], nl=True)], orelse=[Print(dest=None, values=[Str(s='Something else')], nl=True)])])])
[1] fs-boone@zhenghe ~/classes/cs321/hw1 $ ./print-ast.py < test2
Module(body=[If(test=Compare(left=Name(id='x', ctx=Load()), ops=[Eq()], comparators=[Num(n=1)]), body=[Print(dest=None, values=[Num(n=1)], nl=True)], orelse=[If(test=Compare(left=Name(id='x', ctx=Load()), ops=[Eq()], comparators=[Num(n=2)]), body=[Print(dest=None, values=[Num(n=3)], nl=True)], orelse=[Print(dest=None, values=[Str(s='Something else')], nl=True)])])])
[1] fs-boone@zhenghe ~/classes/cs321/hw1 $ diff -u <(./print-ast.py < test1) <(./print-ast.py < test2)
[1] fs-boone@zhenghe ~/classes/cs321/hw1 $ echo $?
0
[1] fs-boone@zhenghe ~/classes/cs321/hw1 $ python --version
Python 2.7.3rc2