get "libhdr"

// Check whether a character is an upper or lowercase letter
let islower(x) = 'a' <= x <= 'z'
let isupper(x) = 'A' <= x <= 'Z'

// Convert a character to upper or lowercase
let toupper(x) = islower(x) -> x - 32, x
let tolower(x) = isupper(x) -> x + 32, x

// Map a character function over a string
let strmap(f,s) = valof
$(  for i=1 to s%0 do s%i := f(s%i)
    resultis s
$)

// Convert a string to upper or lowercase
let strtoupper(s) = strmap(toupper,s)
let strtolower(s) = strmap(tolower,s)

let start() be
$(  let s = "alphaBETA"
    writef("   String: %S*N", s)
    writef("Uppercase: %S*N", strtoupper(s))
    writef("Lowercase: %S*N", strtolower(s))
$)