# TeXtalk: an interview with Peter Grill

Welcome to the TeXtalk! We have a very special guest for today: our friend Peter Grill, 56k+ rep, 301+ badges, and our resident TikZ expert. Get ready for this awesome interview!

Joseph Wright

Dear friends, welcome to the TeXtalk! Our interviewee today is Peter Grill.

Can you start us off by telling us a bit about yourself?

Peter

Sure. Before we start, I wanted thank everyone here that has helped me with my quest to learn LaTeX. I am very grateful for all the support that I have received and can not imagine what I would have done without it. I am not just talking about providing answers to the immediate questions. The community here really does go way above that, always being so friendly and supportive. Oh, and I still have two things that I still need to tackle and that is understanding expansion, and the expl3 syntax. So you know what that means: more expansion questions are coming :-)

I have an engineering background and started of doing chip design, but them moved over to software when I had to do a chip design task for 10 different chips. So, picked up the K&R C Programming book and just kept going. I actually had some push back whether the things I need to do could be automatable, but of course it was.

percusse

Did you implement TeX into any chips, EPROMs etc by any chance?

Peter

:-) No that was way before I knew about TeX.

Garbage Collector

So do you use VHDL language to design chips?

Peter

No, I used in house design tools, and later Verilog for the chip design.

David Carlisle

So is LaTeX a hobby or do you use it for work?

Peter

Well it s a hobby until I actually finish something. I am working on an educational app and hope to have the first versions out in 2013. So LaTeX is my work, just not getting paid for it yet. :-)

percusse

How did you get in contact with (La)TeX?

Peter

Well, I have been thinking of this education app for a while. I was pretty sure that there was some way to typeset the text/math portion, but did not know where to begin. But, I hesitated for a while as I had no idea how to produce nice graphic illustration without hiring a lot of people.

So, then decide well, I’ll hand draw the graphics for now, and then later figure that out. I had used troff many years ago and then goggling came across LaTeX so started looking into that in Dec 2010 when I downloaded the first version and got a basic document to compile. Later I came across TikZ so that solved my graphic issue.

Joseph

You’re one of our leading TikZ experts now: how have you got so good?

egreg

Silver tikz-pgf badge, I should remember.

Peter

Not sure I would consider my self an expert. I really only know \tikzmark well. :-) But all learned by doing – really the only way to learn. Oh, and trying to answer questions before other do always helps to get the adrenaline going.

Just the other day there was a question where the answer was A!1cm!B, and that was something I was not aware of until I there was a question asking for it. I was only familiar with usual A!0.5!B syntax. I have learned a lot by answering questions here.

cmhughes

hi there! :) You have a variety of answers – TikZ being the most. What’s your favourite kind of question to answer?

Peter

Well, I tend to milk the \tikzmark ones for drawing an line from here to there… :-)

cmhughes

:)

tohecz

Do you hunt for rep? :D

David

I could answer that one. :-)

Peter

Well, I tried to keep up with David but I always knew it was futile. However, since he promoted (or is that demoted? :-) ) me to a mathematician I can always be in the top 10 now, so no longer need to hunt for rep. :-)

percusse

You write some of the most well-structured answers. Do you have any other uses for those or just a disciplined approach to TeX.SE? I would really copy/paste some of your answers if I was writing a tutorial on TikZ.

cmhughes

Peter

I naturally tend to provide information in a structured manner – only way I can keep my thoughts straight. And of course I need that for my educational app.

Feel free to copy them. I use those for the the ones where people seem new so that they can get started on TikZ. I know how intimidating TikZ was to me when I first saw it, so hopefully these tutorial style answers help.

cmhughes

Peter

Thanks.

cmhughes

hopefully it’ll get to 100 votes soon :)

Joseph

David Carlisle Won’t like that!

cmhughes

lol :)

Peter

:-)

David

maybe I’ll just translate it to picture mode…

It appears traditional to ask people to name a favourite answer that they have posted. is there any particular one that you are pleased with?

Peter

Well that is an easy one as cmhughes pointed out: Sieve of Eratosthenes in TikZ.

I had been wanting to learn how do an animation and when that I saw the objections to my earlier versions of the answer, I realized that this was the perfect opportunity to learn it — by doing it.

egreg

I’m envious: none of my answers has that many upvotes. :)

Peter

:-)

tohecz

Is there any type of questions that you ignore on the site?

Peter

Well, looking at my ignored tags: lyx, xontext, lautex, minted, xy-pic, plain-tex, pstricks, bibtex

tohecz

lol so many typos, you obviously don’t care about these :p

Peter

Those are things that I just don’t need to use at this time. I originally did not need indexing, but when I needed it started paying attention to those questions.

cmhughes

Do you have a favourite question on the site? Which one have you learnt the most from? :)

Peter

Looking at my very first question Highlight an equation within an align environment you can see how naive I was at that time. I have extraneous packages that are not needed, and was using the color package instead of xcolor.

And then when Jan Hlavacek posted a TikZ solution, I was wondering what this TikZ thing was? At that time it seemed to scary to look at. But I think most people here know how much I use that now – probably responsible for 75% of my rep on this site.:-)

Joseph

How did you first find TeX-sx?

Peter

Well I started to answer that above. Once I started down that LaTeX path I did the same mistake everyone else does, I had a preamble that had sooooooo many packages, most of them I did not know what they were there for. I was trying to figure out how to highlight an equation but do it within an align environment where there additional complications. So I posted my very first question on the main SO site and thankfully it got migrated to TeX.SE.

tohecz

yeah, migration here is a newcomer’s only salvation!

Joseph

Ah right: you knew the main site from mainstream programming?

Peter

Actually, no. I had this question and found SO and registered there and posted it. I did have a programming background, but was not on SO at the time.

tohecz

Have you ever met any TeX.SX members in real life?

Peter

Not yet. Before I decided to learn LaTeX myself, I had posted online looking for local experts to help me along, but found that although they could typeset math equations really well, they did not know much about the fine details, so decided to just learn it myself, and am glad that I did. Don’t think any of them are on here – the ones I met locally.

egreg

Since we’re talking about TeX.SX, what do you think about its pros and cons?

Peter

egreg

I was meaning about the site, first. But also about TeX, if you like.

Peter

I have to say that TeX.SE has been awesome (see my opening remark in case you joined late) as a way to solve my problems, but also a lot fun in solving some of the problems here.

As far as cons: I guess the rep cap is both a pro and a con. I am quite glad it is there, good deterrent to get some other stuff done. :-) Can’t really think about other negatives about the site. But of course, it is the community here that really make the site what it is.

tohecz

damn those rep cap people! :D

percusse

Can you tell us about your journey with xparse and expl3 so far? Are there any tips or warnings for the beginners when coding inside L3 framework ?

Peter

xparse is awesome for building commands, especially with more than one optional parameter, or with default values. But I really don’t know much about expl3, and have reluctantly incorporated some of these solutions into my code. Reluctantly as I won’t be easily able to make any minor changes should they be necessary.

cmhughes

have you always lived in San Jose?

Peter

No, I am actually grew up in Canada. Moved to the San Fran Bay Area in the early 1990s.

tohecz

What are your hobbies, if you omit those computer-science related?

Peter

Well, Film making is a lot of fun, but sure sucks up a lot of time – even more than TeX.SE. Only done short films, and a few have made it to film festivals. Perfect place for a shameless plug: A recent film will be playing at the Underwire Festival 2012 on Nov 21 at Ritzy Picture house at Brixton Oval, Brixton, London. It got nominated for Best Sound Design so is in the “Sonic Sirens” Program.

egreg

You’ll have all UK-TUG among the audience.

Joseph Wright

So you’ll talk next year?

egreg

We can arrange, but I was referring to the fact that you must be at Brixton on Nov. 21.

Peter

Huh? What did I just get signed up for? I guess I could do a talk on “What can’t \tikzmark do?” :-) I don’t think I’ll be able go. The sound designer might be there, and the compose most likely will as well. Let me know if any of you are able to attend.

egreg

Sorry, the line was to Joseph Wright.

percusse

By the way, what’s the title of the movie?

Peter

“Small Sacrifices”. Perhaps we can get Bruno to interview the Sound Designer as they are both at the Univ. of Waterloo.

percusse

\begin{interruptinterview} Thanks for that. I’ll be following it around :) (Here is a small gift for later) \end{interruptinterview}

Peter

Wow that seems quite involved. Will have to view it later. If anyone is interested in finding out more about the short films I have been involved in, email me.

cmhughes

what’s your most frequent use for LaTeX – do you use it on a day-to-day basis for example? :)

Peter

Well, when I am not distracted by other things, such as “life” I pretty much thinking or doing LaTeX all the time. Have even solved a few problems when going to bed. There was a nagging problem I was having and spent a entire day at Starbucks focused on that one problem without getting to the bottom of it. When I was going to sleep I figured it out and then got up really early the next day as I was so excited to see if I had found the problem, and sure enough I had.

cmhughes

you’ve got us all intrigued now – what was the problem?! :)

Peter

I actually don’t remember the details of that particular one – although I could probably figure it out if I looked at my questions posted around that time. I tend to get obsessed with a problem and don’t rest until I get to the bottom of it, or just too tired.

But I have one now where I my preamble works fine, but NOT if I convert to a .fmt file first. Been trying to reduce it down to a MWE, but every time I think I have it, the MWE works just fine!!! So hopefully will have a question soon, unless I figure it out.

egreg

So now you can talk about TeX’s pros and cons. It’s always interesting to know other people’s views of the software.

Peter

Well that is easy: expansion!! I have read and re-read the answers here many times. They mostly make sense to me, but I can never seem to get the correct combination of \expadafters to get it to work. Obviously I don’t understand it. I get the basic use case with \csname foo\endcsname one, but going beyond that is a bit of voodoo magic for me. And this tends to be where I run into problems and am unable to fix it myself.

egreg

Something like \global\expandafter\let\csname foo\expandafter\endcsname\csname bar\endcsname? ;-)

Peter

Oh I didn’t know there was going to be test!! That looks to me as \global\let\foo\bar?

egreg

See? It isn’t that hard! ;-)

Peter

Did I actually get it right? Not sure if I have seen the \expandafter before the \endcsname?

egreg

That’s an old trick, very handy in some cases. But now we have expl3: \cs_gset_eq:cc {foo} {bar} :)

Peter

Ok, now you have lost me. I remember seeing one of your expl3 answer with the comment that the code is pretty self explanatory. :-) It wasn’t for me.

tohecz

LOL, I know that feeling.

Peter

Yeah I guess once we learn to read expl3 it will be obvious, but until then it’s all greek (or Klingon) to me.

tohecz

yes!!!

egreg

Apart from expansion, what do you find hard and what easy in TeX? You’ve got very proficient in just two years.

Peter

I tend to be able to solve most other problems. But since I have such a complex preamble it takes a while to get it down to a MWE. Like my recent question: Incompatibility between currfile and enumitem, it was strange that enumerate worked fine, but itemize did not.

Don’t know the tricks to get to the bottom of such problems in a more efficient manner than combing my preamble into one file and then slowing removing packages, macros.

cmhughes

Not so much a question, but I just want to say thank you for everything that you do on the site – your answers, questions, and comments are always helpful to everyone :)

egreg

Are you planning to come to Europe some day?

Peter

Haven’t been to Europe in a while. Actually did my final year of high school in Neuchatel, Switzerland. Do hope to get there someday. Just need a good excuse. :-)

Hey, that’s not fair. Gonzalo Medina is taking this an opportunity to get even further ahead!! :-)

tohecz

just now? that’s naughty!

Peter

:-)

egreg

How do you start when answering a question?

Peter

I think it depends on the question. For the tutorial ones I try to capture the actual steps I go thru as I develop the solution and then just write it up as I figured it out.

My hope is that that will help others realize that going thru the intermediate steps where you don’t immediately get what you want is really the only way to solve things.

Similarly with math I think it is is often just as important to know what did not work, and understand why it did not work.

egreg

That’s surely true for math. And also for teaching in general, I believe.

Peter

I wish more math students would realize that the actual answer is not really that important. If you already know the answer than you are not really learning.

tohecz

Have you ever thought of being a teacher?

Peter

Yeah I do like tutoring math, and did consider teaching, but then got to work on my app, so have to finish that first and see how it does.

tohecz

Because your way of thinking would make you a good teacher!

Peter

Thanks.

percusse

Just to get it out of the way: What are the cons, or your complaints about TikZ? (Pros we all know and addicted anyway :) )

Peter

TikZ was scary at first, but then got the hang of it to do basic stuff. One of the cons definitely is its syntax checking as evidenced by my latest “embarrassing” question: Computed coordinates are all the same?. I also find if strange when there are optional parameters to the optional parameters, which I still do not have the hang of yet.

But is output looks really nice, so can’t complain too much.

Qrrbrbirlbel

But you are apparently not the only one that has problems with TikZ’ special syntax: +11 on the question and +8 on the answer.

Peter

Yeah, I recall that Martin Scharrer in one of his early answer’s had said it was strange that he would get so many up vote on something that was almost trivial (well at least to someone who knows), yet very little upvotes on something that required quite some time to get it to work. So I guess one can interpret that others have similar issues.

Sometimes after having spent a bit of time to figure out an answer, and then seeing that it does not get any up votes makes me think that there must be something wrong with it, or perhaps I mis-understood the question. But I guess if the OP does not respond, best to just leave it.

Qrrbrbirlbel

I hear you. Some easy answers get more upvotes than answers where you have invested quite a lot of time. But what are you going to do? I guess, it’s easier to upvote short things where you can easily say “Yeah, seems about right.”

egreg

We discussed this other times. Answers to difficult questions tend to be difficult and understanding them requires going deep into (La)TeX’s (or TikZ’s) way of doing things. So it’s quite normal that both the question and the answer don’t receive upvotes.

Peter

Yep. But still would be nice to get some feedback from the OP.

There was even an easier one, not to pick on Gonzalo, but the answer was to use \text{} within display math mode.

tohecz

I know one: I kept getting “Dimension too large!” with TikZ at random places.

egreg

We need 64 bit TeX. :) You can do the conversion, the source is available. :)

Peter

:-)

egreg

We could print on a sheet of paper larger than a cricket ground.

Peter

:-) Am hoping that was not the dimension where the problem is. :-)

egreg

By the way, what’s your preferred sport to do or watch?

Peter

I guess than that is your trademark. Sort of like Alfred Hitchcock, or M. Night Shyamalan making an appearance in his films, or 1138 in Lucas’s films. :-)

egreg

That was only to keep David happy. Actually I know almost nothing about cricket.

Peter

Oh, I thought you were the resident expert on cricket.

David

Don’t tell but I don’t know anything about it either, I originally inserted it just to break up a screenful of Juventus discussion:-)

egreg

So, you’re not into sports?

Peter

You mean besides getting rep on TeX.SE? :-) I tend to not like watching sports too much unless I know some one who is playing. I’d rather play, but then again, I haven’t really done much in the way of sports for a long time.

egreg

Next projects, besides completing your LaTeX based application and making movies?

Peter

Good question. I think if the apps take off then that could easily turn into a company to grow it as there are other related opportunities, but am more focused on getting my current one done for now.

egreg

A LaTeX based company? WOW! Well, probably LaTeX is only a part of it. :)

Peter

Yeah LaTeX would be to produce the content. Not part of the end product.

egreg

I’ll claim for a discount when my department will buy it. :)

Peter

No problem. I’d be willing to pay for that. :-)

Joseph

Friends, it looks like we are about out of questions: any more?

egreg

I’d thank Peter for the time he dedicates to TeX.SX and for this enjoyable interview.

Joseph

Indeed, thank you very much Peter.

Peter

Well, in closing, I wanted to say that if anyone is out in the San Francisco Bay already, please do let me know. I owe quite a few people here some beers. :-) I’d be fun to actually meet some of you. Oh, and of course a tour would be included.

Just stay away from late Dec, and tax time: Mid March to April 15, and mid Sep to Oct 15, any other time should be good.

tohecz

Indeed it would be fun!

egreg

Including “Infinite Loop 1, Cupertino”, of course. :)

Peter

Sure, and can share some personal stories about Steve in person…

Stay tuned for the next episode of TeXtalk!

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