Why '==' ??

Josiah Carlson jcarlson at uci.edu
Wed Mar 31 11:52:38 CEST 2004


> if a = 3 
>    print 'Yeah baby'
> 
> are still *unambiguous*.... yet the interpreter refuses to understand
> you......

Oh, the CPython interpreter understands you, it just doesn't like what 
you say.  I (and I'm sure the majority of other Python users) agree with 
the interpreter, your modified syntax leaves something to be desired.

You syntax also /makes ambiguous/ the following currently valid Python 
syntax...

if a == 3: \
     print "hello"

If we converted that to /your/ syntax, it would read...

if a = 3 \
     print "hello"

Which would get internally translated to...

if a = 3 print "hello"

I don't think it makes sense, and I wouldn't expect an interpreter to 
think it makes sense of it either.


> Theres no reason why a single '=' shouldn't be understood in a
> conditional....

Except that it would be a 'special case' when two different syntactical 
symbols mean the same thing.
"Special cases aren't special enough to break the rules."
  - The Zen of Python, by Tim Peters

> As for needing a ':' to allow statements after a 'def' or a
> conditional.... python already has the ';' for that... why insist on a
> ':'

Do you even read the docs?  Python does not have ';' to allow statements 
after a def, Python has ';' because it allows you to place more than one 
statement on a single line.  That is, it allows...
a = 1;b = 2;c = 3;

/not/ because it allows the absolutely ugly:
def fun(a,b): print a,; print b;

You should note that ':' is placed in syntactically different locations 
than ';', because they have syntactically different meanings.  ':' means 
"there is some scope that is being enclosed", while ';' means "that is 
the end of the previous statement".


  - Josiah



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