-- Result matching: match ~v (ok arm) and ^e (err arm) on R ok err values.
-- ~ wraps a value in Ok, ^ wraps in Err.
-- Auto-unwrap with ! propagates Err to the calling function.
-- Parse a text literal and match the result
parse-ok>t;r=num "3.14";?r{~v:str v;^e:"err"}
parse-bad>t;r=num "oops";?r{~v:"ok";^e:"err: "+e}
-- Safe division returning R n t, matched at call site
safe-div a:n b:n>R n t;=b 0 ^"zero";~/a b
div-msg a:n b:n>t;r=safe-div a b;?r{~v:str v;^e:"fail: "+e}
-- Auto-unwrap: inner returns R; outer propagates Err automatically
inner x:n>R n t;~*x 2
outer x:n>R n t;r=inner! x;~+r 1
-- run: parse-ok
-- out: 3.14
-- run: parse-bad
-- out: err: oops
-- run: div-msg 10 2
-- out: 5
-- run: div-msg 10 0
-- out: fail: zero
-- run: outer 5
-- out: ~11