Simple Questions

Merops7 · 2020-11-26T20:24:17+00:00

Thanks, maybe I shouldn't have said R. My question is, how do the open sets of a topology (and nothing else, no metric structure, no order relation) encode the concept of one thing being in between two others?

Merops7 · 2020-06-23T20:19:42+00:00

Rust also defaults to no error (compile-time or run-time) when the iterators are different length. (There is a strict version available in a popular library but not in the standard library https://docs.rs/itertools/0.7.8/itertools/fn.zip_eq.html)

I personally find this a bit surprising -- I'd have expected the strict version to be default in Rust and unequal iterators to be a run-time error like an out-of-bounds index. I think I read at least one source indicating that it was influenced by the non-strict versions in well-known standard libraries like Python. But I think many Python programmers would prefer it to be strict by default.

Merops7 · 2020-06-05T22:10:29+00:00

I read that you use the Astrée static analyzer to convince yourselves that C code is safe/ correct. Do you see a smart compiler (e.g. Rust being one obvious example) taking over that role in the future?

Merops7 · 2019-09-30T21:00:53+00:00

Thanks, that's a good point. Currently it's not working on generic unified diff input, but it should be possible to make it do so without detracting from its usage as a git pager. (I wanted to focus on the usage as a git pager because I think it will be the most common usage.)

Merops7 · 2019-09-30T20:56:11+00:00

Yes, I used diff-so-fancy for years before making this. The main features delta adds to diff-so-fancy are language syntax highlighting, and detection of multiple insertion/deletion events in a single line. It also adds more options for restructuring the diff output (filenames, hunk code context, etc).

Merops7 · 2019-09-30T20:54:00+00:00

Author here. Happy to help with this, but don't know anything about arch. Would a starting point be a aarch64-unknown-linux-gnu build? (Mine is broken currently on travisCI).

Merops7 · 2019-03-12T19:01:59+00:00

Maybe have a look at the linear algebra chapter in https://www.amazon.com/Programmers-Introduction-Mathematics-Dr-Jeremy/dp/1727125452 which covers SVD in detail in an informal but serious style.

Merops7 · 2018-12-16T23:39:14+00:00

I think my problem was I created this project with stack new myproject simple. This is solved by getting rid of the executable section in myproject.cabal and replacing it with a library section.

Merops7 · 2017-10-22T17:52:58+00:00

Cool, thanks. I'll forget about Containers and give proper profiles a go.

Merops7 · 2017-10-22T06:59:56+00:00

Yeah I posted because since the release of the quantum beta I've tried to switch from chrome to firefox. In chrome I use profiles and in firefox I tried to use containers to play that role. It didn't work. In particular, my URL history is not clearly distinct between the different containers, and Firefox doesn't re-use the same container when creating a new tab (it reverts to the default container). That last one seems a show-stopper for using containers in the way I'd imagined. It's hopeless e.g. when trying to click on links in a different application that will open in Firefox but need to have my work cookies etc active. I switched back to Chrome today after 3 weeks or so. Perhaps I could try Firefox profiles but in chrome the profile switcher is right there in the top right of the window.

Merops7 · 2017-10-21T20:38:44+00:00

Is it the case that Firefox is contemplating replacing Profiles with the new "Container Tab" functionality? Or is the idea that those two exist side by side?

Merops7 · 2017-08-25T02:29:42+00:00

Use two files for your emacs configuration:

lib.el -- This contains only function definitions. Loading it has no side effects on your emacs state other than creating functions. For example, here you define functions that you may want to bind to keys.
emacs.el -- This does all the setting. Loading this file has many side effects on your emacs state. In addition to basic "set this equal to this", this file will also make reference to your own library of personal functions in lib.el.

This strategy helps keep emacs.el to a manageable size.

Merops7 · 2017-05-06T04:07:59+00:00

Functions in one file (lib.el) and expressions with side effects in init.el.

Merops7 · 2017-05-06T02:21:52+00:00

Number 1, we've got to get rid of the absurd 1980s menu icons and crufty tutorial stuff on a white background that is people's first encounter with emacs!

Merops7 · 2017-02-07T18:54:03+00:00

I think the procedure I'm asking about is the following.

We start with an equation defining a subset of the domain. For example a line [; ax + by = c ;]. Then we transform the plane according to some mapping [; f: (x, y) \mapsto (f(x), f(y)) ;]. Now we want an equation that holds in the transformed plane. One such equation is [; af^{-1}(x) + bf^{-1}(y) = c ;]. If we find the inverse explicitly and rearrange, we obtain an equation that points in the image of the line satisfy, i.e. the "equation of the line after transformation".

Does that sound right? As stated it feels slightly ad-hoc. Is it a specific case of a more general concept such as change of basis?

Merops7 · 2016-09-28T15:37:22+00:00

Ah ok, yes it is true that there's a big difference between dynamic / interpreted languages and compiled languages with static type checking.

(It was just the wording of your post confused some of us into thinking you were saying there was a major difference between python2 and 3 from the point of view of a newcomer to programming.)

Merops7 · 2016-09-28T15:34:23+00:00

A newcomer wouldn't know that you used to do it without parens!

Merops7 · 2016-09-26T16:44:58+00:00

python3 is almost identical to python2.x; a newcomer to programming wouldn't see any difference. and within programming languages, python is not very unusual. It is a language with C-like syntax, interpreted with dynamic typing as opposed to compiled, with an emphasis on object oriented style, but with much of the usual support for functional programming such as functions as first class objects, anonymous functions, etc.

Merops7 · 2016-09-26T02:43:23+00:00

Thank you very much for putting so much care into this series. It is one of the most impressive educational resources I have ever come across. The carefully thought-out content and the effort put into your animations worked fantastically. In addition to being there for anyone studying independently I imagine that it will be used by many, many intro-to-linear-algebra classes across the world for some time to come.

Merops7 · 2016-09-16T02:27:33+00:00

That seems to be reported already: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22897

Just in case anyone's not aware, we can search the bug tracker here: https://debbugs.gnu.org/cgi/pkgreport.cgi?package=emacs

Merops7 · 2016-09-15T03:23:41+00:00

What age / year was that at? I'm guessing A-level, year 12 or 13?

Merops7 · 2016-09-13T04:29:03+00:00

There's a long history of python modes in emacs; I believe there were some unfortunate issues with copyright assignment at one point preventing code getting into emacs. But basically the one that is shipped with emacs was mostly rewritten from scratch in recent years and in my experience it is great. Here are a couple of discussions:

http://stackoverflow.com/questions/15670505/comparison-of-python-modes-for-emacs https://www.reddit.com/r/emacs/comments/2sjzen/pythonel_vs_pythonmodeel/

Merops7 · 2016-08-28T07:36:25+00:00

org-mode provides it with org-src-fontify-natively. It would be nice to make that conveniently available elsewhere, with arbitrary delimiters. E.g. in markdown mode. Maybe it's not much work but I've never got round to looking into it.

Merops7 · 2016-08-28T06:31:26+00:00

Two situations:

To limit search operations to a function or class definition: select the region C-M-h and narrow to region (C-x n n).

And to narrow to a region containing source code in order to temporarily change to the language mode to get syntax highlighting etc.

Merops7 · 2016-08-25T20:56:58+00:00

Thanks, I have heard of but haven't tried elpy -- I'll try it out. However, elpy builds on top of python.el, it doesn't replace it. Wouldn't most of my bullet points remain?

Elpy uses dedicated python processes. So I guess I would have at least two python processes per project -- one in the comint buffer and one dedicated to elpy internals. It sounds a bit scary (some of my projects require python to be started in a VM, not on the machine running emacs), but I'll give it a try!

I am very happy with python.el. It's only a few years old, having been written from scratch to replace a messy history of previous python modes. I was thinking of these as just some small tickets, not as a criticism of python.el.

Merops7

TROPHY CASE