I stumbled upon a discussion about the Gnome Calculator. Apparently it stopped working for some people because a bank blocked it from retrieving the exchange rates it needs to allow users to do currency conversions. I get it. It's a feature, it needs data that's up to date, so you need to fetch it. The default is to do this once a week, I hear.
Based on currency-provider.vala, the currency providers are the International Monetary Fund (IMF) and the European Central Bank.
So that leads me to another question: What do you use to do calculations you can't do in your head?
I mostly do it in Emacs using `M-x calc`. It uses the reverse-polish notation (RPN) I am used to from my old calculators before there where smartphones. For a while I used `bc` but the precision was weird. Then I tried `dc` but it was weird, too. Now I have Super+C bound to `orpie` running in a terminal. Perhaps I should bind that key to run `emacsclient` and eval `(calc)`. 😂
From the replies, I found a large number of people reporting that they used the interpreters of their favourite programming languages. I didn't know that this was so wide-spread. People named Python, Ruby, Fennel, Scheme.
Python:
Python 3.11.2 (main, Nov 30 2024, 21:22:50) [GCC 12.2.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> 1+2+3 6
Ruby:
irb(main):001:0> 1+2+3 => 6
Fennel:
Welcome to fennel! >> (+ 1 2 3) 6
Chicken Scheme:
CHICKEN (c) 2008-2021, The CHICKEN Team (c) 2000-2007, Felix L. Winkelmann Version 5.3.0 (rev e31bbee5) linux-unix-gnu-x86-64 [ 64bit dload ptables ] Type ,? for help. #;1> (+ 1 2 3) 6
@HaraldKi@nrw.social shared that they use a shell, but not just any shell: `tclsh` with the expr built-in command.
Tclsh uses just double math, afair, and understands plain and simple everyday expressions you basically learned in primary school. Plus scientific notation like 2.7e22 . Plus a chunk of log, sin, cos, tan if really needed. So no brain tweaks needed. The only thing to keep in mind: add .0 to most numbers to not accidentally get 3/4 -> 0.
The key is have a function in your shell that gets transformed into a Tcl command that is piped to `tclsh`. In my case, using `fish`, use `funced calc --save` and use the following:
function calc
echo "puts [expr {$args}]" | tclsh
end
At the shell prompt:
> calc 1+2+3 6 > calc 4/3 1 > calc 4/3.0 1.3333333333333333
What about the other options?
I think the key is that they have to startup fast and be ready to type. `bc` certainly qualifies. Just remember to set the scale! Or use the `--mathlib` option.
bc 1.07.1 Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006, 2008, 2012-2017 Free Software Foundation, Inc. This is free software with ABSOLUTELY NO WARRANTY. For details type `warranty'. 1+2+3 6 4/3 1 scale=3 4/3 1.333
`dc` has reverse-polish notation (RPN) but is very terse. Tokens are separated by spaces or newlines. Thus, the Enter key doesn't print a result. You need to use the `p` command. Again, the default is integer math. Use the `k` command to switch scale.
1 2 3 + + p 6 4 3 / p 1 3 k 4 3 / p 1.333
A weird part is that you need to enter negative numbers using the underscore (`_3` for -3).
By contrast, my favourite calculator in the terminal right now is `orpie`. You get reverse-polish notation and immediate feedback.
Orpie v1.6.1 -- swap drop dup view | 25:
--------------------------------------| 24:
Calculator Modes: | 23:
angle: RAD base: DEC complex: REC | 22:
| 21:
Common Operations: | 20:
enter : <return> | 19:
drop : \ | 18:
swap : <pagedown> | 17:
backspace: \177 | 16:
add : + | 15:
subtract : - | 14:
multiply : * | 13:
divide : / | 12:
y^x : ^ | 11:
negation : n | 10:
Miscellaneous: | 9:
scientific notation : <space> | 8:
abbreviation entry mode : ' | 7:
stack browsing mode : <up> | 6:
refresh display : C-L | 5:
quit : Q | 4:
| 3:
| 2: 6
| 1: 1.33333333333333
--------------------------------------------------------------------------------
Emacs comes with `M-x quick-calc` which simply asks for an expression and prints the result:
Result: 1 + 2 + 3 => 6 (16#6, 8#6, 2#110, "^F")
Then there's `M-x calculator` which comes with its own mode. You can use `o h` to switch output to hex, for example. So adding up 1 + 2 + 3 + 4 results in 10, or A in hex.
Calc==H> A
And finally there is `M-x calc`. Check out the short tutorials by Andrew Hyatt, if you're interested in learning more. As I said above, this is my default solution. `1 RET 2 RET 3 RET + +` and there we go. Plus a trail over on the right in case you're confused.
---------------------- Emacs Calculator Mode ---------------------- |----- Emacs Calculator Trail -----
1: 6 | 1
. | 2
| 3
| + 5
| +>6
|
|
-UUU:%*--F1 Calc: 12 Deg All L2 (Calculator) ---------------|-UUU:%*--F1 *Calc Trail* All L5
Copying the result runs into a tiny problem, for me: The stack depth is copied along with it! So if you copy the above result (6), what you actually get is `1: 6`. Which is never what I want to paste elsewhere. Never.
@kickingvegas@sfba.social suggested casual-calc, which is part of "a project to re-imagine the primary user interface for Emacs using keyboard-driven menus".
@m@helvede.net suggested qcalc which also offers “currency conversion”:
The exchange rates can be updated manually using File → Update Exchange Rates, or automatically at specific intervals (by default once every week, but this can be changed in the preferences dialog), when needed (when currencies are converted).
Apparently it gets the exchange rates from the European Central Bank and Coinbase App APIs.
Another option is spreadsheets, of course. @neauoire@merveilles.town mentioned nebu. I don't have a Varvara system up and running, however.
There is `sc`, of course. If you don't want to hit `=` for every number you enter, use `-n` for "quick numeric entry". I'm not sure how I can quickly select the range for something like `@sum(A0:A2)` but it certainly seems possible to use `sc` for interesting stuff.
B2 (10 2 0) [B0/B1]
A B C D E F G
0 1.00 4.00
1 2.00 3.00
2 3.00 1.33
3 6.00
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Visidata (`vd`) also looks interesting. Sadly I have no idea how to do anything. 😂
File Edit View Column Row Data Plot System Help Ctrl+H for help menu directory │ filename ║ ext │ size #│ modtime 1› .| BUTTON1_RELEASED no-op 0 files •0
Of course, Emacs also comes with a spreadsheet. Visit an empty file ending with `.ses`. Enter a number. To add a new row, use `down` then create a new cell using `TAB` and enter a second number. When you need a formula, use `(apply ses+ (ses-range A1 A3))`, for example.
File Edit Options Buffers Tools SES Help
A B C D
1
2
3
6
#Calculators #Spreadsheets #Software