Comment by neilv

This is a nice example of one way to implement DSLs in a language that doesn't support them well.

IIUC, they're using Lua's language's function application syntax, combined with the ability to introduce a different namespace environment for function lookup, and then they're evaluating the tree of function calls at run time.

In languages that support doing this at compile time, through compile-time evaluation or compile-time syntax transformation, you can make run time faster. For example of syntax transformation, https://www.neilvandyke.org/racket/html-template/ shows an example of expanded syntax, where it's rendered some of the angle brackets and coalesced that with (escaped) HTML CDATA.

If you wanted to extend that, to support chunks of traditional HTML angle-bracket syntax inline with code (without using string literals), like in React, you could define a Racket reader to parse those chunks and transform them to parentheses syntax above.