Emacs Tree-sitter custom highlighting, part 3 #
In the last post I described how, for a particular project with certain naming conventions, I wanted to use emacs tree-sitter font-locking to highlight variables that might be used in the wrong context:
I found a way to make it work for simple expressions but it was relying on regular expression matching rather than tree-sitter parse trees. I set a goal of handling these types of expressions:
elevation_t[t] // good elevation_t[r] // bug elevation_t[t_from_r[r]] // good elevation_t[r_from_t[t]] // bug elevation_t[obj.t] // good elevation_t[obj.r] // bug elevation_t[t_from_r(r)] // good elevation_t[r_from_t(t)] // bug elevation_t[x.t_fn(x)] // good elevation_t[x.r_fn(x)] // bug elevation_t[x.t_arr[i]] // good elevation_t[x.r_arr[i]] // bug elevation_t[(t)] // good elevation_t[(r)] // bug
Labels: emacs
Emacs Tree-sitter custom highlighting, part 2 #
In the last post I described my initial attempt at customizing font-lock using Emacs 29 tree-sitter. Regular font locking uses regular expression matching. Tree sitter allows combining regular expression matching with parse tree matching, like "variable declaration" or "function call". The ideas I came up with were mostly things that I could have implemented with regular expressions alone, but I wanted to experiment with the tree sitter approach. Here's the effect of conventional highlighting, using color for keywords and other syntax:
Labels: emacs