[Python-Dev] PEP 292, Simpler String Substitutions

Christian Tismer tismer@tismer.com
Thu, 20 Jun 2002 13:52:06 +0200

Fredrik Lundh wrote:
> christian wrote:
>>>I usually mention "import" in the first hour (before methods),
>>>and nobody has ever had any problem with that...
>>Well, same here, but that might change, since the string
>>module is nearly obsolete. You can show reasonably
>>powerful stuff(*) without a single import.
>>(*) and that's what you need to get people interested.
> I usually start out with something web-oriented (which means
> urllib).  how about adding a "get" method to strings?  or an "L"
> prefix character that causes Python to wrap it up in a simple
> URL container:
>     print url"http://www.python.org".read()


> but in practice, if you really want people to get interested,
> make sure you have a domain-specific library installed on the
> training machines.  why care about string fiddling when your
> second python program (after print "hello world") can be:

Yes, I know. I didn't want to make a point, just to point
out that it is possible to show neat stuff without import.
Sure, the next thing I show is COM stuff or formatted stock
market reports, using urllib, xml... -- no point.

--- the rest below is not to Fredrik but the whole thread ---

I'd like to express my opinion at this place (which is as good
as any other place in such a much-too-fast growing thread):

The following statements are ordered by increasing hate.
1 - I do hate the idea of introducing a "$" sign at all.
2 - giving "$" special meaning in strings via a module
3 - doing it as a builtin function
4 - allowing it to address local/global variables

Version 4 as worst comes visually quite close to
languages like Perl. In another post, Guido answered
such objection with "grow up". While my emotional
reaction would be to reply with "wake up!", I have some
rationale reasons why I don't like this:

I have to read and sometimes write lots of Perl code.
The massive use of "$" gives me true headache. I don't
want Python to remind me of headaches.

One argument was that "$" and the unembraced usage in "$name"
is so common and therefore easy to sell to Python newbies.
Fine, but no reason to adopt this overly abused character.
Instead, I'm happy that exactly "$" is nowhere used in
I don't want to make Python similar to something, but to
keep it different in this aspect. Like the triple quotes,
the percent formatting exists rather seldom in other
languages, and I love to use templates for makefiles,
scripts and whatsoever, where I don't have to care too
much about escaping the escapes.
With an upcoming "$" feature, I fear that "%" might get
abandoned in some future, and I loose this benefit.

I agree with any sensible extension/refinement of the "%" sign.
I disagree on using "$" for anything frequent in Python.
I don't want to see variable names as placeholder inside
of strings. Placeholders should be dictionary string keys,
but this dictionary must be obtained explicitly.
I do like the allvars() proposal.

crap-py -ly - chris

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