-- Type conversions: str (number to text), num (text to number R n t).
-- str: converts any number to text; integers format without .0.
-- num: parses text to number, returns R n t (Ok or Err).
-- Number to text
n-to-t>t;str 42
-- Float to text
f-to-t>t;str 3.14
-- Negative to text
neg-to-t>t;str -7
-- Text to number: ok case
t-to-n>t;r=num "42";?r{~v:str v;^e:"err"}
-- Text to number: error case
bad-parse>t;r=num "abc";?r{~v:"ok";^e:+"bad: " e}
-- run: n-to-t
-- out: 42
-- run: f-to-t
-- out: 3.14
-- run: neg-to-t
-- out: -7
-- run: t-to-n
-- out: 42
-- run: bad-parse
-- out: bad: abc