yowl 0.1.0

Primitives for reading and writing the SMILES language
Documentation 
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use std::convert::TryFrom;
use std::fmt;

/// Represents the virtual hydrogen count on a bracket atom.
/// See: [Hydrogen Suppression in SMILES](https://depth-first.com/articles/2020/06/08/hydrogen-suppression-in-smiles/).
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum VirtualHydrogen {
    H0,
    H1,
    H2,
    H3,
    H4,
    H5,
    H6,
    H7,
    H8,
    H9,
}

impl VirtualHydrogen {
    /// Returns true if the count is zero, or false otherwise.
    pub fn is_zero(&self) -> bool {
        self == &Self::H0
    }
}

impl TryFrom<u8> for VirtualHydrogen {
    type Error = ();

    fn try_from(count: u8) -> Result<Self, Self::Error> {
        match count {
            0 => Ok(Self::H0),
            1 => Ok(Self::H1),
            2 => Ok(Self::H2),
            3 => Ok(Self::H3),
            4 => Ok(Self::H4),
            5 => Ok(Self::H5),
            6 => Ok(Self::H6),
            7 => Ok(Self::H7),
            8 => Ok(Self::H8),
            9 => Ok(Self::H9),
            _ => Err(()),
        }
    }
}

impl From<&VirtualHydrogen> for u8 {
    fn from(val: &VirtualHydrogen) -> Self {
        match val {
            VirtualHydrogen::H0 => 0,
            VirtualHydrogen::H1 => 1,
            VirtualHydrogen::H2 => 2,
            VirtualHydrogen::H3 => 3,
            VirtualHydrogen::H4 => 4,
            VirtualHydrogen::H5 => 5,
            VirtualHydrogen::H6 => 6,
            VirtualHydrogen::H7 => 7,
            VirtualHydrogen::H8 => 8,
            VirtualHydrogen::H9 => 9,
        }
    }
}

impl fmt::Display for VirtualHydrogen {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(
            f,
            "{}",
            match self {
                Self::H0 => "",
                Self::H1 => "H",
                Self::H2 => "H2",
                Self::H3 => "H3",
                Self::H4 => "H4",
                Self::H5 => "H5",
                Self::H6 => "H6",
                Self::H7 => "H7",
                Self::H8 => "H8",
                Self::H9 => "H9",
            }
        )
    }
}