[Reduce-algebra-developers] reduce on termux

[Andrey G. G. <A.G...@in...>]

Hello *,

I first installed Linux in 1994, on a 386 PC with 8 Mbytes. I used it, in 
particular, to run reduce. Now my arm64 android phone in my pocket (as 
well as my android tablet) is several orders of magnitude more powerful 
than that computer in 1994. Therefore, there is a natural desire to run 
reduce on them.

It is possible to run a full-featured Linux on an android device. Almost. 
It is termux. No rooting needed. Normally, it is a command-line Linux, 
though there is a rather complicated way to run X programs in it (in any 
case, X programs on a phone are useless; on a tablet, they may be usable). 
Don't install termux from play.google.com! Download apk from 
https://github.com/termux/termux-app/releases or 
https://f-droid.org/en/packages/com.termux/ and install it. You will have 
a command-line Linux which tries to be similar to Debian, with a rather 
large set of packages. A good screen keyboard (with ctrl, alt, tab, etc.) 
is needed; I recomment the hacker's keyboard 
https://play.google.com/store/search?q=hacker%27s%20keyboard&c=apps

Now, thanks to Arthur Norman, it is possible to build and run reduce on 
termux. Download the latest reduce from svn to your home directory in 
termux. Probably, you will want to

pkg install bash

(the default shell in termux is dash). Then run

scripts/termux-sanity-check.sh

it will install the necessory dependences. Then

./configure --with-csl --without-gui
make

Running ./configure will take some time, be patient. make will probably 
stop after some errors in libedit; nevermind, it is only needed for 
redfront, and the bare csl reduce already has 90% of useful functionality 
of redfront built in. Then

cd cslbuild/*/csl
make reduce.img

If you like Lisp, you can also make csl.image to have csl as a free 
bonus. Then return to the top-level reduce directory and say

bin/redcsl

Happy reducing! This is a native arm64 program, not some java shit.

Why would you want to have reduce in your pocket? There are many reasons. 
The most trivial one is: reduce is a far more convenient and powerful 
calculator than any android calculator. Just say

on rounded;

and input the expression you want to calculate in the familiar 
mathematical notation. Not via these horrid emulations of extinct pocket 
calculators.

Many thanks to Arthur for his great work,
Andrey