On Sat, 8 Jul 2000, Paul Prescod wrote:
Ping says:
As it stands, with both 8-bit strings and Unicode strings, i think this would result in too much hidden complexity -- thinking about this can wait until we have only one string type.
I don't see any hidden complexity. Python has features specifically designed to allow this sort of thing on a per-type basis.
Well... what happens when the other operand is a Unicode string? Do you also do automatic coercion when adding something to a Unicode string? When you add one to an arbitrary object, how do you convert the other object into a Unicode string? When you add an 8-bit string and Unicode together, what do you get? It's not that i don't think you might be able to come up with consistent rules. I just suspect that when you do, it might amount to more hidden stuff than i'm comfortable with. Of course you could also just use Itpl.py :) or a built-in version of same (Am i half-serious? Half-kidding? Well, let's just throw it out there...). Instead of: print PaulsString("abcdef")+5 print open+PaulsString("ghijkl") with Itpl.py it would just be: printpl("abcdef${5}") printpl("${open}ghijkl") A built-in Itpl-like operator might almost be justifiable, actually... i mean, we already have "%(open)sghijkl" % globals() Well, i don't know. Perhaps it looks too frighteningly like Perl. Anyway, the rules as implemented (see http://www.lfw.org/python/ for the actual Itpl.py module) are: 1. $$ becomes $ 2. ${ } around any expression evaluates the expression 3. $ followed by identifier, followed by zero or more of: a. .identifier b. [identifier] c. (identifier) evaluates the expression What i'm getting at with this approach is that you are clear from the start that the goal is a string: you have this string thing, and you're going to insert some stringified expressions and objects into it. I think it's clearer & less error-prone for interpolation to be its own operation, rather than overloading +. It also means you could start with a Unicode string with $s in it, and you would be assured of ending up with a Unicode string, for example. -- ?!ng