On Thu, 22 Dec 2022, at 20:20, Phil Smith III wrote:
> Jeremy-you realize that PostScript is about as far as you can get from
> markup in a lot of ways, right? It's fun stuff but not what people generally
> mean when they say "markup". Just sayin'.
Good point!
When I used DCF, I wrote a lot of macros; my most complex set used two
separate definitions of a whole set of macros; the first set were used on
the first pass through a set of related documents and generated a whole
set of intermediate files. Then the second set of definitions were used
for a conventional 2-pass process to generate the final documents,
reading both the original files and all the intermediate ones.
So to some extent it's the programmability that I really miss - and the
facility for embedded comments. The PS example has both. If one
defines a tailored set of macros (or - in PS - PS commands eg in the
building plans file, a command to draw a wall) then the source file
becomes at least in part a long sequence of commands, interspersed
with text to be placed on the page. Eg, near the start of the file there's
this
/smoke_alarm % S: x_pos y_pos %{{
{ newpath 1 index 1 index 80 0 360 arc 1 index 1 index
60 0 360 arc 40 0 360 arc stroke } def
which is a definition (the trailing "def") of a macro named "smoke_alarm"
(which draws a symbol consisting of three concentric circles). It takes
2 parameters (off the stack) which are the x and y positions on the
page where it is to go).
Later on in the file we have for example: 4200 7000 smoke_alarm
(and quite a few other calls).
My main criticism of the way the PS was written is that there's too
many instances of actual numbers. I'd rather have seen eg smoke
alarm positions defined in terms of the symbolic locations of the
nearby walls, and the distance from a wall that an alarm should be
placed at. It'd make the code easier to understand too.
--
Jeremy Nicoll - my opinions are my own.
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