The second module of the old erlang_decimal library: conversion between {coef, exp} decimals and binaries, charlists and floats.

Unlike :decimal, which is a thin shim over the Elixir Decimal library, this module is a direct port of the original Erlang source. The parser and the float printer decide which strings are valid and which digits a float produces, and those decisions have to match the original exactly — including the badarg raised on malformed input.