Welcome, apprentice.

You have stumbled upon the lang-wiz — a private grimoire of the more advanced incantations of the Go programming arts. Each page pairs a spell's runes (the code) with a slow, looping vision of the magic at work. Twiddle the dials; the runes light up where the world has shifted, and the vision changes accordingly. No prior necromancy required.

Tip: a great wizard reads slowly. The animations are deliberately unhurried so the eye may catch each glimmer.

Table of spells

• Singleflight Bind many summoners to a single casting. The familiar fetches once, all receive the same scroll.
• WaitGroup Tally your apprentices; do not leave the tower until each has returned.
• Context A leash of intent — cancel a working spell from across the chamber.
• Channels Whispering tubes between goroutines. Mind the buffer.
• Errgroup Coordinate a coven; one falter halts the rite.
• Mutex A single wand passed hand to hand; only one apprentice may stir the cauldron.