The most useful construct I am aware of that I wish became more popular in backend languages is strongly typed tree literals. (Introduced by Meta in Hack as "XH

The most useful construct I am aware of that I wish became more popular in backend languages is strongly typed tree literals. (Introduced by Meta in Hack as "XHP") Consider this pseudocode expression: :Div{Hello :Span(style='bold'){world}} # expression type: HTMLDOMNode.Div This is immensely powerful and saves a ton of time/bugs especially when compared to the alternative of string interpolation. I know somebody once did XHP on Python, but regrettably this work was abandoned.