[ZPT] Truncating strings

[Eron Lloyd]

On Tuesday October 21 2003 5:01 pm, Ian Bicking wrote:
> On Tuesday, October 21, 2003, at 03:32 PM, Eron Lloyd wrote:
> > Does anyone know of a simple way to truncate string insertions in a
> > ZPT? What
> > I'm looking for is basically a replacement for dtml-var's "size" and
> > "etc"
> > attributes. I would do it on the MySQL side but that doesn't seem to
> > have
> > such a function, either.
>
> Maybe just do it Python-like:
>
> <span tal:condition="python: len(var) > 10" tal:omit-tag="">
>    <span tal:replace="python: var[:10]">var</span>...
> </span>
> <span tal:condition="python: len(var) < 10" tal:omit-tag="">
>    <span tal:replace="var">var</span>
> </span>

Yeah, I considered this...

> Well, that's not very appealing, is it?  Or a Python Script:
>
> #truncate
> #parameters=s, length=10, etc='...'
> s = str(s)
> if len(s) > length:
>      return s[:length] + etc
> else:
>      return s
>
> <span tal:replace="python: container.truncate(var, 10,
> etc='...(more)...')">var</span>

This looks good.

> Really ZPT (TALES really) is painfully in need of easy-to-access
> formatters.  I saw discussions of it long ago in the archives, but is
> there any progress on this?  E.g.:
>
> <span tal:replace="var" tal:format="formatters/truncate">var</span>
>
> Or:
>
> <span tal:replace="var" tal:format="python:
> formatters.truncate(5)">var</span>

Yes! And then there are the other formatters, such as dollars-and-cents, 
thousands-comma, etc. that could be added back.

> Where tal:format operates on the result of tal:replace or tal:content.
> This implies some sort of currying, like:
>
> #truncate
> #parameters=length=10, etc='...'
> def format(s, length=length, etc=etc):
>      if len(str(s)) > length:
>          return str(s)[:length] + etc
>      else:
>          return str(s)
> return format
>
> How higher-level functions interact with TALES, I'm not sure... but if
> it's more difficult, it matters much less that the formatters are easy
> to program, compared to being easy to use.  Or maybe this is really
> just the importing problem, because this would be just as good:
>
> <span tal:replace="structure python: formatters.truncate(var,
> 10)">var</span>
>
> [I think tal:format would imply structure]  But the current access to
> these sorts of functions through the modules variable is painful at
> best.  And it seems like the functions in PythonScripts.standard are a
> little sparse.

Do any of the core ZPT developers have any comments on this great idea?

> But really the second example isn't so bad, I suppose
> (container.truncate).

Not at all. Thanks a bunch.

> --
> Ian Bicking | ianb at colorstudy.com | http://blog.ianbicking.org

Eron
-- 
Eron Lloyd
Technology Coordinator
Lancaster County Library
elloyd at lancaster.lib.pa.us
Phone: 717-239-2116
Fax: 717-394-3083

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