Currently both arguments of the boolean operators "and" and "or" are evaluated at compile time. impement short cut semantics because everybody expects this.
Possible solutions:
- Follow Python's implementation closely:
- At compile time call `argument.__bool__()` and decide in special purpose code.
- For generated code use special function which is converted by code generator back into shortcut
operator. (Similar to current implementation.)
- Implement idea from Greg Ewing (PEP 335: http://www.python.org/dev/peps/pep-0335/):
- Special methods for boolean operators `and`, `or`.
To retain the shortcut semantics split the execution of the
operator into two phases:
- first call `__and1__(self)`, `__or1__(self)` if these operators
can compute the result they return `True`/`False`; otherwise they
return the special value !NeedOtherOperand.
- if !NeedOtherOperand was returned call:
`__and2__(self, other)`, `__rand2__(self, other)`
return the special value `NeedOtherOperand`.
- if `NeedOtherOperand` was returned call:
`__and2__(self, other)`, `__rand2__(self, other)`
- Calls with unknown arguments always end up as: `__xx2__`
(this is implemented)
https://sourceforge.net/apps/trac/freeode/ticket/37
