FUNCTION

The function to invoke for styling. It should accept the original send phrase being styled, plus the phrase that was produced by a macro, if one was applied, otherwise the original send phrase again. Most functions are only interested in the first argument, but some, like the variable-use macro's styler, require access to the resulting variable-use phrase, to get to the declaration that it's a use of, so that it can determine if it should be styled as a use of a constant, variable, function argument, etc.