def octal

bolt@1.27.0.0 · src/rules/correctness/escape.bend:37

import Base

37# the Sym's char when it is an octal digit
38def octal(ss: Sym) -> Maybe<&2, Char>:
39  match ss:
40    case SZero{}:
41      Some{'0'}
42    case SDigit{Chr{+x}}:
43      Bool.pick(Maybe<&2, Char>, U32.is_le(x, 55), Some{Chr{x}}, None{})
44    case other:
45      None{}