Re^3: An infix fix

I really like the simplicity and symmetry, but I was (and still am) a little hung up on making them behave as their 2-argument operators do. So I certainly can't hold your pedantry against you. :-)

If you call them ANY and ALL, I go with your definitions. As AND and OR, I think they should behave as the ops: AND returns the first false value, or the last true value if no false values are encountered; OR returns the first true value, or the last false value if no true values are encountered. That definition extends easily to one argument, but leaves the zero-argument case undefined.

Caution: Contents may have been coded under pressure.

Comment on Re^3: An infix fix

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Re^4: An infix fix by tlm (Prior) on Mar 22, 2005 at 23:37 UTC
As AND and OR, I think they should behave as the ops: AND returns the first false value, or the last true value if no false values are encountered; OR returns the first true value, or the last false value if no true values are encountered. I'd be curious to learn how the languages that have multi-arg `AND` and `OR` resolve this question. Of the languages I'm familiar with only Scheme fits this description, and, at least in the Scheme implementations I have on my machine (PLT Scheme/mzscheme and MIT Scheme), `(and)` is true and `(or)` is false; e.g. (for MIT Scheme): `1 ]=> (and) ;Value: #t 1 ]=> (and 3) ;Value: 3 1 ]=> (and 0) ;Value: 0 1 ]=> (or) ;Value: () 1 ]=> (or 3) ;Value: 3 1 ]=> (or 0) ;Value: 0` [download] The way I understand these generalized versions of these functions is that AND is false if any of its arguments is false, true otherwise; OR is true if any of its arguments is true, false otherwise. In this formulation, the case of no arguments is not problematic. the lowliest monk	[reply] [d/l] [select]
Re^5: An infix fix by Roy Johnson (Monsignor) on Mar 23, 2005 at 00:13 UTC
Scheme appears to be behaving as I described, returning operand values. It also has special behavior for no-argument cases. Note that `(and 3)` is not the same as `(and 3 #t)`, so recursing down to the empty list will not emulate its behavior. I don't object to defining the zero-arguments case; I just object to using it as the basis for nonzero-argument cases. It is a special case: `sub AND { @_ > 1 ? shift && AND(@_) : @_ ? shift : '#t'; }` [download] Caution: Contents may have been coded under pressure.	[reply] [d/l] [select]