Re: Ampersand in Metapost

[Mojca Miklavec <mojca.miklavec.lists@gmail.com>]

On Fri, May 14, 2010 at 12:06, Marco wrote:
> On Fri, 14 May 2010 00:37:44 +0200, Mojca Miklavec wrote:
>
>> PS: I would say: better use \sometxt which is far more reliable unless
>> you have to use textext to do string manipulation.
> I don't know exactly which transformations are considered as »string
> manipulation«. I've read your MyWay on \sometxt. Brilliant piece of doc. But
> I've three questions.
>
>   i) Is it about MkII, MkIV or both?

It's mostly about MkII. In MKIV it should work, but it doesn't make
such a huge difference since textext works as well as \sometxt in
MkII. textext in MkII can sometimes be very inefficient.

>  ii) Is it still up-to-date?

Apart from a recently reported bug I don't know of any changes in
MkII, but maybe I should write a few words about MkIV.

>  iii) Why should I better use \sometxt?

> What do you mean by »more reliable«? After having read your MyWay I would say
> that textext is more reliable because it can do dynamic text.

Dynamic text counts as "feature" for me, not as "something that'"

> I created a testfile to compare textext and \sometxt. The points to compare
> were those you mentionend in your MyWay as advantages of \sometxt. The
> testfile »t.tex« is attached. I processed it with
>
> ConTeXt  ver: 2010.05.08
> luatex, version beta-0.60.1-2010042821

As already mentioned by Hans, the only difference,

> Here are my results:
>
> -There is one obvious reason: speed
>
> Average runtime:
>    textext  variant: 56s
>    \sometxt variant: 57s
>
> That is the same. Maybe my test file is not appropriate to test the speed. I'm
> sure you have performed more advanced tests.

For gnuplot-generated graphics compile time has been reduced from 10
minutes to 20 seconds. But that's another story (many graphics, many
text labels inside each graphic; textext was not optimized).

> -Document-wide definitions are seen
>  [...] definitions with arguments will fail to work.
>
> The first line, a document-wide definition with arguments works in both
> versions.

But that's only true with MkIV. In MKII it's another story.

> -Problems with expansion
>  [...]  as far as I remember math expressions (fractions perhaps) never
>  worked as they were supposed to
>
> The second definition is a math expressions with fractions. It seems to work.

Many math expressions have later been made unexpandable and started
working, but it felt like a neverending story. Almost the same as the
example that you were asking for.

> I know, your MyWay is old. Maybe some things are fixed now. But I don't see
> many advantages for me using it.

If you are using MkIV and don't run into the same problem again, there
is hardly a difference.

> In fact, I have a problem getting random colors working. Take the following
> example (taken from my earlier thread).
>
> % This line is needed to get »withcolor« to work?
Yes, in MkII. In MkIV Hans wanted to take a different approach.
> \chardef\TeXtextcolormode\zerocount

> % Produces empty rectangles
> for i=0 downto -3:
>  ran;
>  label(\sometxt{\bold{Test}}, (7cm,-4cm))
>    rotatedaround ((7cm,-4cm),i*20)
>    withcolor transparent("normal", .2, (r,g,b));
> endfor;

Hans replied.

All in all - true, the most difference is seen in MkII.

Mojca
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