1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124

use std::convert::TryFrom;
use std::fmt::{self, Display, Formatter};

#[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
pub enum Value {
    Int(u32),
    Str(String),
}

impl Value {
    #[inline]
    pub fn into_bool(&self) -> bool {
        self.into()
    }

    pub fn type_name(&self) -> &'static str {
        match self {
            Value::Int(..) => "int",
            Value::Str(..) => "str",
        }
    }
}

impl Display for Value {
    #[inline]
    fn fmt(&self, formatter: &mut Formatter) -> fmt::Result {
        match self {
            Value::Int(num) => num.fmt(formatter),
            Value::Str(str) => formatter.write_str(str),
        }
    }
}

impl From<bool> for Value {
    #[inline]
    fn from(b: bool) -> Self {
        if b {
            Value::Int(1)
        } else {
            Value::Int(0)
        }
    }
}

impl<'a> From<Value> for bool {
    #[inline]
    fn from(v: Value) -> Self {
        match v {
            Value::Int(i) => i != 0,
            Value::Str(s) => !s.is_empty(),
        }
    }
}

impl<'a> From<&'a Value> for bool {
    #[inline]
    fn from(v: &'a Value) -> Self {
        match v {
            Value::Int(i) => *i != 0,
            Value::Str(s) => !s.is_empty(),
        }
    }
}

impl From<u32> for Value {
    #[inline]
    fn from(n: u32) -> Self {
        Value::Int(n)
    }
}

impl From<String> for Value {
    #[inline]
    fn from(s: String) -> Self {
        Value::Str(s)
    }
}

impl<'a> From<&'a str> for Value {
    #[inline]
    fn from(s: &'a str) -> Self {
        Value::Str(s.to_string())
    }
}

/// Contains actual type name
#[derive(Debug)]
pub struct ValueConvertError(pub &'static str);

impl TryFrom<Value> for u32 {
    type Error = ValueConvertError;

    #[inline]
    fn try_from(v: Value) -> Result<Self, Self::Error> {
        match v {
            Value::Int(n) => Ok(n),
            _ => Err(ValueConvertError(v.type_name())),
        }
    }
}

impl TryFrom<Value> for usize {
    type Error = ValueConvertError;

    #[inline]
    fn try_from(v: Value) -> Result<Self, Self::Error> {
        match v {
            Value::Int(n) => Ok(n as usize),
            _ => Err(ValueConvertError(v.type_name())),
        }
    }
}

impl TryFrom<Value> for String {
    type Error = ValueConvertError;

    #[inline]
    fn try_from(v: Value) -> Result<Self, Self::Error> {
        match v {
            Value::Str(s) => Ok(s),
            _ => Err(ValueConvertError(v.type_name())),
        }
    }
}