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Date:         Mon, 22 Jul 2013 09:40:03 -0700
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From: Paul Thompson <patjah@SBCGLOBAL.NET>
Subject: Re: Propagation of 'global'ness
To: LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
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I work with the SAS macro language, which is very similar to the LaTeX macr=
o expansion language. In that language, the scope (global vs local vs local=
ly - global) is governed by a symbol status table, which is centrally defin=
ed. The status of the variable can be queried and defined, the status of th=
e variable is defined by its first reference, and the default is local. In =
that way, much is quite similar to the LaTeX approach. The main difference =
is that there is a master symbol table which contains the status of all var=
iables.=0A=0A=0A=A0=0APaul Thompson =0A=0A=0AProfessor and Senior Scientist=
=0ADirector, Methodology and Data Analysis Center=0ASanford Research/USD=0A=
2301 E 60th St N=0ASioux Falls, SD    57104=0A=0A=0AO: 605-312-6462=A0=A0 M=
: 618-974-0473=A0 H: 605-332-1587=A0 F: 605-328-0401=0A=0A=0A909 N. Charles=
ton Circle=0ASioux Falls, SD 57110=0A605-332-1587=0A=0A=0A_________________=
_______________=0A From: Joseph Wright <joseph.wright@MORNINGSTAR2.CO.UK>=
=0ATo: LATEX-L@LISTSERV.UNI-HEIDELBERG.DE =0ASent: Monday, July 22, 2013 10=
:10 AM=0ASubject: Re: Propagation of 'global'ness=0A =0A=0AOn 22/07/2013 09=
:06, Michiel Helvensteijn wrote:=0A> On Mon, Jul 22, 2013 at 9:43 AM, Josep=
h Wright=0A> <joseph.wright@morningstar2.co.uk> wrote:=0A> =0A>> Certainly =
see a point here, but on the other hand I'm not a fan of=0A>> encouraging m=
ore and more data structures. Writing a full data structure=0A>> module is =
non-trivial: in most cases, I'd expect people to be using=0A>> combinations=
 of the existing ones in an ad-hoc fashion for their purpose.=0A> =0A> That=
 doesn't sound like someone who is creating a programming language. :-)=0A>=
 =0A> Abstraction is the word. There are so many useful data structures out=
=0A> there that you haven't even touched upon in the libraries yet. Graphs,=
=0A> trees, priority queues, sets, multisets, tables, ... One can never=0A>=
 predict what a programming language will be used for.=0A=0ACertainly true,=
 hence waiting with interest to see what Bruno has in=0Amind about 'objects=
'.=0A=0AI was thinking more that if we look at other languages there are a=
=0Alimited number of data types, and for specialist applications you still=
=0Ahave to use whatever 'base' types are available. Now, we of course=0Area=
lly only have macros and TeX's build-in registers, but if we are=0Aallowed =
a little leeway then we come to the kernel-defined data types we=0Aalready =
have.=0A=0AI've no real experience of other languages, though, so perhaps I=
 miss=0Asomething. What does one do in say C if the data structures availab=
le=0Aare not suitable? (I didn't think you could even add keywords in most=
=0Alanguages, so adding data types seems tricky.)=0A=0A[BTW, I'd hope expl3=
 is used for 'typesetting', broadly :-) Bruno may=0Awant to pilot the Mars =
rover in TeX, but ...]=0A=0A> If you see a future in expl3 you should expec=
t it to grow, and outside=0A> developers to be a part of that. If you don't=
 provide these kinds of=0A> facilities, others will. That's the nature of T=
eX. Just look at=0A> etoolbox, etc. Being more flexible will probably give =
you more control=0A> in the long run.=0A=0AGrow certainly, but the question=
 is at least in part whether that's at=0Athe programmers tools side or on t=
he real business of TeX: typesetting=0Aand appropriate tools.=0A-- =0AJosep=
h Wright
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<html><body><div style=3D"color:#000; background-color:#fff; font-family:bo=
okman old style, new york, times, serif;font-size:12pt">I work with the SAS=
 macro language, which is very similar to the LaTeX macro expansion languag=
e. In that language, the scope (global vs local vs locally - global) is gov=
erned by a symbol status table, which is centrally defined. The status of t=
he variable can be queried and defined, the status of the variable is defin=
ed by its first reference, and the default is local. In that way, much is q=
uite similar to the LaTeX approach. The main difference is that there is a =
master symbol table which contains the status of all variables.<br><div><sp=
an><br></span></div><div>&nbsp;</div><div>Paul Thompson <br><br></div><div>=
Professor and Senior Scientist<br>Director, Methodology and Data Analysis C=
enter<br>Sanford Research/USD<br>2301 E 60th St N<br>Sioux Falls, SD    571=
04</div><br><br><div>O: 605-312-6462&nbsp;&nbsp; M: 618-974-0473&nbsp;
 H: 605-332-1587&nbsp; F: 605-328-0401</div><div><br><br></div><div>909 N. =
Charleston Circle<br>Sioux Falls, SD 57110<br>605-332-1587<br>  <div style=
=3D"font-family: bookman old style, new york, times, serif; font-size: 12pt=
;"> <div style=3D"font-family: times new roman, new york, times, serif; fon=
t-size: 12pt;"> <div dir=3D"ltr"> <hr size=3D"1">  <font face=3D"Arial" siz=
e=3D"2"> <b><span style=3D"font-weight:bold;">From:</span></b> Joseph Wrigh=
t &lt;joseph.wright@MORNINGSTAR2.CO.UK&gt;<br> <b><span style=3D"font-weigh=
t: bold;">To:</span></b> LATEX-L@LISTSERV.UNI-HEIDELBERG.DE <br> <b><span s=
tyle=3D"font-weight: bold;">Sent:</span></b> Monday, July 22, 2013 10:10 AM=
<br> <b><span style=3D"font-weight: bold;">Subject:</span></b> Re: Propagat=
ion of 'global'ness<br> </font> </div> <div class=3D"y_msg_container"><br>=
=0AOn 22/07/2013 09:06, Michiel Helvensteijn wrote:<br>&gt; On Mon, Jul 22,=
 2013 at 9:43 AM, Joseph Wright<br>&gt; &lt;<a ymailto=3D"mailto:joseph.wri=
ght@morningstar2.co.uk" href=3D"mailto:joseph.wright@morningstar2.co.uk">jo=
seph.wright@morningstar2.co.uk</a>&gt; wrote:<br>&gt; <br>&gt;&gt; Certainl=
y see a point here, but on the other hand I'm not a fan of<br>&gt;&gt; enco=
uraging more and more data structures. Writing a full data structure<br>&gt=
;&gt; module is non-trivial: in most cases, I'd expect people to be using<b=
r>&gt;&gt; combinations of the existing ones in an ad-hoc fashion for their=
 purpose.<br>&gt; <br>&gt; That doesn't sound like someone who is creating =
a programming language. :-)<br>&gt; <br>&gt; Abstraction is the word. There=
 are so many useful data structures out<br>&gt; there that you haven't even=
 touched upon in the libraries yet. Graphs,<br>&gt; trees, priority queues,=
 sets, multisets, tables, ... One can never<br>&gt; predict what a
 programming language will be used for.<br><br>Certainly true, hence waitin=
g with interest to see what Bruno has in<br>mind about 'objects'.<br><br>I =
was thinking more that if we look at other languages there are a<br>limited=
 number of data types, and for specialist applications you still<br>have to=
 use whatever 'base' types are available. Now, we of course<br>really only =
have macros and TeX's build-in registers, but if we are<br>allowed a little=
 leeway then we come to the kernel-defined data types we<br>already have.<b=
r><br>I've no real experience of other languages, though, so perhaps I miss=
<br>something. What does one do in say C if the data structures available<b=
r>are not suitable? (I didn't think you could even add keywords in most<br>=
languages, so adding data types seems tricky.)<br><br>[BTW, I'd hope expl3 =
is used for 'typesetting', broadly :-) Bruno may<br>want to pilot the Mars =
rover in TeX, but ...]<br><br>&gt; If you see a future in expl3 you
 should expect it to grow, and outside<br>&gt; developers to be a part of t=
hat. If you don't provide these kinds of<br>&gt; facilities, others will. T=
hat's the nature of TeX. Just look at<br>&gt; etoolbox, etc. Being more fle=
xible will probably give you more control<br>&gt; in the long run.<br><br>G=
row certainly, but the question is at least in part whether that's at<br>th=
e programmers tools side or on the real business of TeX: typesetting<br>and=
 appropriate tools.<br>-- <br>Joseph Wright<br><br><br></div> </div> </div>=
  </div></div></body></html>
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