colon-with-characters.R

# Making the colon operator work with characters
# A response to https://twitter.com/carroll_jono/status/1162932405516193793
# This is a stupid implementation, since it will hurt performance of any other usage of :
# Better to do it in C or C++

# Make : into an S3 generic
`:` <- function(x, y, ...) {
  UseMethod(":")
}

# For convenience
charToInt <- function(x) {
  utf8ToInt(substring(x, 1, 1))
}

# Assume the input is UTF8
`:.character` <- function(x, y, ...) {
  i <- charToInt(x)
  j <- charToInt(y)
  intToUtf8(i:j, multiple = TRUE)
}

# For any non-character input, leave : as it is
`:.default` <- function(x, y, ...) {
  base::`:`(x, y, ...)
}

# Usage is, e.g.,
"a":"e"
"base":"tidy"
1:5