(EDIT: I replaced asterisks with <AST> in the pattern below, since HN doesn't have a convenient way to escape asterisks last I checked.) > First, most of its s

(EDIT: I replaced asterisks with <AST> in the pattern below, since HN doesn't have a convenient way to escape asterisks last I checked.) > First, most of its syntax beyond the very basics like "X+" or "[^X]" is impossible to remember. It’d be nice to know what "(?<!X)" does without having to look it up first. I realize regex can be hard to remember, but I think this is a little overblown. "(? ...)" is the general form of an extended group -- something for which "special behavior" occurs. The character sequence following that determines what the special behavior is. In this case, "<!" means "negative lookbehind": "<" for "lookbehind" and "!" for "negative". Compact, but mnemonic. > [a-z]{3,10}://([^/?#]<AST>)([^?#]<AST>)(?:\?([^#]<AST>))?(?:#(.<AST>))? Yes, this is very dense. But it's not really meant to be read at a glance -- URLs do not have an exceptionally simple pattern, and they have multiple parts, many of which are optional. You could write a recognizer for URLs explicitly, but I doubt it would be as immediately recognizable in full. I consider it more important to obtain a high-level understanding before a low-level understanding, and (for me at least) I can see that this regex matches URLs up front, setting my expectations for the details later. I think a PEG or combinator parser would be more self-documenting, so I'm not saying regex can't be pushed too far. But it isn't nearly as unstructured as it looks. > Many DSLs were designed to reduce amount of non-DSL code to the absolute zero. They try to help too much. I 100% agree here. A DSL should be laser-focused on doing one thing well. Any language should be composed of orthogonal features, each laser-focused; a DSL is just a language with a very small handful of features geared toward a specific domain. (Of course, ideals are rarely realized in full.) I particularly like GraphQL as of recently; it has a really nice feel to it. I found an interesting paper [0] on design principles for DSLs while composing this comment. I've only skimmed it, but it looks quite nice. [0] https://arxiv.org/abs/1409.2378 https://arxiv.org/abs/1409.2378