pub type InternalDimensionFn = Rc<dyn Fn(&Token) -> Result<Option<RegisterValue>>>;Expand description
A package-installed resolver for control sequences that yield an internal
dimension by reading their own argument — e.g. calc.sty’s \widthof{box}.
Given the already-read CS token, it either consumes that CS’s argument(s)
from the gullet and returns the measured value (Ok(Some(_))), or leaves
the stream untouched and declines (Ok(None)), in which case the caller
un-reads the token. Keeps core calc-agnostic: the base dimension reader
consults this seam before giving up with “Missing number”, so
\makebox[\widthof{X}] / \rule{\widthof{X}}{…} resolve like real LaTeX
without \widthof having to be a register (which would change its bare
digestion). See calc_sty.rs / OXIDIZED_DESIGN #115.
Aliased Type§
pub struct InternalDimensionFn { /* private fields */ }