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https://buttondown.email/hillelwayne/archive/why-do-regexes-use-and-as-line-anchors/
Last week I fell into a bit of a rabbit hole: why do regular expressions use $ and ^ as line anchors?1
This talk brings up that they first appeared in Ken Thompson's port of the QED text editor. In his manual he writes: b) "^" is a regular expression which matches character at the beginning of a line.
c) "$" is a regular expression which matches character before the character (usually at the end of a line)
QED was the precursor to ed, which was instrumental in popularizing regexes, so a lot of its design choices stuck.
Okay, but then why did Ken Thompson choose those characters?
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Why Do Regexes Use `$` and `^` as Line Anchors?
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When you dig another out of trouble, you've got a place to bury your own.
(Score: 2, Interesting) by Anonymous Coward on Thursday March 28 2024, @04:42PM
User-selectable alternate stylesheets were an original design feature of CSS but it's unfortunate that the browser support today is completely useless.
The CSS2 specification actually says that user agents must provide an interface to change between alternate stylesheets [w3.org]. I don't know if this requirement persists in current specifications. Firefox has the choice in a hidden menu but it forgets your selection as soon as you reload the page or follow any link so it's basically unusable. Such a shame.