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1### `++sub`
3Subtract
5Subtracts `b` from `a`.
7Accepts
8-------
10`a` is an atom.
12`b` is an atom.
14Produces
15--------
17An atom.
19Source
20------
22 ++ sub :: subtract
23 ~/ %sub
24 |= [a=@ b=@]
25 ~| %subtract-underflow
26 ^- @
27 ?: =(0 b) a
28 $(a (dec a), b (dec b))
30Examples
31--------
33 ~zod/try=> (sub 10 5)
34 5
35 ~zod/try=> (sub 243 44)
36 199
37 ~zod/try=> (sub 5 0)
38 5
39 ~zod/try=> (sub 0 5)
40 ! subtract-underflow
41 ! exit
45***