-- String operations: hd, tl, slc, rev, srt, trm on text values.
-- hd/tl/slc/rev/srt work on individual characters; trm strips whitespace.
-- First character of a string
first-ch s:t>t;hd s
-- All but first character
rest-ch s:t>t;tl s
-- Slice characters from index 0 to 3
prefix s:t>t;slc s 0 3
-- Reverse a string
rev-str s:t>t;rev s
-- Sort characters alphabetically
sort-chars s:t>t;srt s
-- Trim whitespace (hardcoded so spaces survive CLI parsing)
trim-demo>t;trm " hello "
-- run: first-ch hello
-- out: h
-- run: rest-ch hello
-- out: ello
-- run: prefix abcdef
-- out: abc
-- run: rev-str hello
-- out: olleh
-- run: sort-chars dcba
-- out: abcd
-- run: trim-demo
-- out: hello