On choosing a good syntax for the EBNF specification of your programming language: https://dwheeler.com/essays/dont-use-iso-14977-ebnf.html
Related Posts
Blogging about my programming language project: choosing the basic syntax!
https://www.garden-lang.org/blog/syntax.html
In praise of Tcl, and reflecting on syntax features for a good command shell: https://yosefk.com/blog/i-cant-believe-im-praising-tcl.html
I've added syntax highlighting to the prompt of my programming language!
It's not strictly necessary, but it's nice to have. It caught a bug with lexing incomplete string literals too.