chr is:exact -package:esqueleto

chr :: Int -> Char
base Data.Char GHC.Char, protolude Protolude, haskell-gi-base Data.GI.Base.ShortPrelude, relude Relude.Base, rio RIO.Char.Partial, base-prelude BasePrelude, universum Universum.Base, Cabal-syntax Distribution.Compat.Prelude, rebase Rebase.Prelude, hledger Hledger.Cli.Script, unicode-data Unicode.Char, incipit-base Incipit.Base, cabal-install-solver Distribution.Solver.Compat.Prelude
The toEnum method restricted to the type Char.
chr :: SInteger -> SChar
sbv Data.SBV.Char
Conversion from an integer to a character. 
>>> prove $ \x -> 0 .<= x .&& x .< 256 .=> ord (chr x) .== x
Q.E.D.

>>> prove $ \x -> chr (ord x) .== x
Q.E.D.
chr :: Expr Int32 -> Expr Text
rel8 Rel8.Expr.Text
Corresponds to the chr function.