replace_one: Replace left or right pole of constructs with blanks
Description
To display the two poles of the constructs as vertex labels with different
colors, the poles have to be printed twice. The helper function replaces all letters
from one of the poles with blanks.
Usage
replace_one(x, first = TRUE)
replace_all(x, first = TRUE)
Arguments
x
Character vector of constructs with `@` sign used to separate construct poles.
first
Replace first pole (`TRUE`) or second pole (`FALSE`)