dandrake

Motivation: removing speaker notes from slides

I make reveal.js slides with markdown and convert with pandoc. Sometimes I want to post those slides so my students can access them, but I want to strip out the speaker notes because they usually aren't very useful to them.

Solution: use a pandoc filter

I don't want to edit my source files; I just want the output correct. So, I could do something to the output html slides.

But: I also want to allow for the possibility that I'll want to output to other formats. So the best solution is to tell pandoc to do that filtering while it converts.

dandrake

(defun my/do-command-other-window (count command &optional return-p)
  "Do COMMAND in other-window. The COUNT argument is provided to
`other-window'.

The optional RETURN-P argument, if true, will make this return to the
original window after calling COMMAND.

The intended way to use this function is by calling it from an
interactive function that specifies the command:

dandrake

public enum Coffee {
    ESPRESSO(2.50, 2),
    LATTE(4.50, 8),
    CAPPUCCINO(4.00, 8),
    AMERICANO(3.00, 8);

    // the 'final' isn't necessary functionally, since you can't change these from outside the class/enum
    // but this does document our intent, and would prevent accidentally adding something inside this enum
    // that modified the field.
    private final double price;

dandrake

# my version of Steve Reich's Clapping for Sonic Pi:
# https://en.wikipedia.org/wiki/Clapping_Music
# https://youtu.be/lzkOFJMI5i8?si=oaBTc4WBR_DC2SJJ
# https://sonic-pi.net/

use_bpm 120

claps = [1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0].ring

live_loop :clapping do

dandrake

#lang racket

#|

I'm trying to understand parameters in Racket.

One idea: for a recursive function,
have a parameter that says how much to indent a debugging print
statement so that I can see the call stack more clearly.

dandrake

A macro that creates constants in Racket

Inspired by this Racket discourse post I tried writing a macro that defines bindings that work like constants in Racket.

Note that the solution here handles using set!; you can't prevent shadowing or redefining these variables -- see the Discourse thread.

dandrake

#lang racket/base


;; This is lovely but Exercism doesn't let you (require math)!
;;
;; Posted this: https://gist.github.com/dandrake/d9a3e20021a68ed16bce6f5dc79e62eb



(require racket/contract)

dandrake

<!--

You want to use your phone as a flashlight, but using the camera flash
is (1) too bright, and (2) is white and is jarring at night if you want
just a bit of dim light.

So you want, say, a dim, red light.

There are apps that turn your entire screen some color, but you don't
need that. Just transfer this HTML page to your phone and load it up in

dandrake

If you run

#lang dtc/frames/animations
(animate `(1 2 3))

as a script from the command line in Ubuntu 25.04, the result is:

invalid memory reference. Some debugging context lost

dandrake

#!/usr/bin/env racket

;;;; Support code for my shell "gitcd" function: if you are in a git
;;;; repo, but not in the worktree part -- you're in a regular repo
;;;; somewhere inside the .git directory, or in a bare git repo -- the
;;;; usual "git rev-parse --show-toplevel" stuff doesn't work.
;;;;
;;;; The code here detects those situations where rev-parse fails: it
;;;; looks for either ".git" somewhere in the current directory's
;;;; ancestry, or "reponame.git" in the cwd ancestry.