Comment #7 on issue 1887 by [email protected]: Separate boolean and
symbolic relationals
http://code.google.com/p/sympy/issues/detail?id=1887
Mmmm... that's not obvious.
First, concerning (symbolic) equations, I successively concidered:
1. Using Ineqn:
---------------
I thought about having an Ineqn(a, b, comp) class. Something like that:
Ineqn(x, 2, '>')
x > 2
Ineqn('x>2')
x > 2
Ineqn('3>2')
3 > 2
(Le, Lt etc. might then be kept as shortcuts for inequations...)
But Ineqn.args should all be of Basic type, so this would require to
convert third argument ('>', '<', '>=', '<=' and maybe '!=') to Integers
for example, for internal storage. That's feasable but not so elegant.
Nevertheless, I like the name Ineqn, which IMO does not suggest booleans as
much as Le or Lt.
2. Keeping Lt, Le...
--------------------
Another option is of course to use Le, Lt... for symbolic inequations, but
I don't like it so much, I think it really looks like boolean names.
3. Using GtEqn, LeEqn
---------------------
GtEqn, LeEqn (and so on...) are less ambiguous, but not so short to tape.
GtEqn(x, 2)
x > 2
LeEqn(3, 5)
3 <= 5
For now, I think it's the solution I prefer.
Concerning inequalities:
The real challenge is to find suitable names for symbolic inequations (ie.
short and unambiguous ones).
As for (boolean) inequalities, I think names are not so important, since x
< 2 is an easy shortcut.
Also, inequalities (but not inequations) should auto-reduce to True or
False in cases like S(3) < S(4) and S(3) > S(4).
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