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
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142

// Copyright (C) 2019-2023 Aleo Systems Inc.
// This file is part of the snarkVM library.

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use super::*;

impl<E: Environment> Parser for Field<E> {
    /// Parses a string into a field circuit.
    #[inline]
    fn parse(string: &str) -> ParserResult<Self> {
        // Parse the optional negative sign '-' from the string.
        let (string, negation) = map(opt(tag("-")), |neg: Option<&str>| neg.is_some())(string)?;
        // Parse the digits from the string.
        let (string, primitive) = recognize(many1(terminated(one_of("0123456789"), many0(char('_')))))(string)?;
        // Parse the value from the string.
        let (string, value): (&str, E::Field) =
            map_res(tag(Self::type_name()), |_| primitive.replace('_', "").parse())(string)?;
        // Negate the value if the negative sign was present.
        let value = match negation {
            true => -value,
            false => value,
        };

        Ok((string, Field::new(value)))
    }
}

impl<E: Environment> FromStr for Field<E> {
    type Err = Error;

    /// Parses a string into a field.
    #[inline]
    fn from_str(string: &str) -> Result<Self> {
        match Self::parse(string) {
            Ok((remainder, object)) => {
                // Ensure the remainder is empty.
                ensure!(remainder.is_empty(), "Failed to parse string. Found invalid character in: \"{remainder}\"");
                // Return the object.
                Ok(object)
            }
            Err(error) => bail!("Failed to parse string. {error}"),
        }
    }
}

impl<E: Environment> Debug for Field<E> {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        Display::fmt(self, f)
    }
}

impl<E: Environment> Display for Field<E> {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        write!(f, "{}{}", self.field, Self::type_name())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use snarkvm_console_network_environment::Console;

    type CurrentEnvironment = Console;

    const ITERATIONS: u64 = 10_000;

    #[test]
    fn test_parse() -> Result<()> {
        let rng = &mut TestRng::default();

        // Ensure empty value fails.
        assert!(Field::<CurrentEnvironment>::parse(Field::<CurrentEnvironment>::type_name()).is_err());
        assert!(Field::<CurrentEnvironment>::parse("").is_err());

        for _ in 0..ITERATIONS {
            // Sample a random value.
            let field: <CurrentEnvironment as Environment>::Field = Uniform::rand(rng);

            let expected = format!("{}{}", field, Field::<CurrentEnvironment>::type_name());
            let (remainder, candidate) = Field::<CurrentEnvironment>::parse(&expected).unwrap();
            assert_eq!(format!("{expected}"), candidate.to_string());
            assert_eq!("", remainder);
        }
        Ok(())
    }

    #[test]
    fn test_display() {
        /// Attempts to construct a field from the given element,
        /// format it in display mode, and recover a field from it.
        fn check_display<E: Environment>(element: E::Field) {
            let candidate = Field::<E>::new(element);
            assert_eq!(format!("{element}{}", Field::<E>::type_name()), format!("{candidate}"));

            let candidate_recovered = Field::<E>::from_str(&format!("{candidate}")).unwrap();
            assert_eq!(candidate, candidate_recovered);
        }

        let mut rng = TestRng::default();

        for _ in 0..ITERATIONS {
            let element = Uniform::rand(&mut rng);

            check_display::<CurrentEnvironment>(element);
        }
    }

    #[test]
    fn test_display_zero() {
        let zero = <CurrentEnvironment as Environment>::Field::zero();

        let candidate = Field::<CurrentEnvironment>::new(zero);
        assert_eq!("0field", &format!("{candidate}"));
    }

    #[test]
    fn test_display_one() {
        let one = <CurrentEnvironment as Environment>::Field::one();

        let candidate = Field::<CurrentEnvironment>::new(one);
        assert_eq!("1field", &format!("{candidate}"));
    }

    #[test]
    fn test_display_two() {
        let one = <CurrentEnvironment as Environment>::Field::one();
        let two = one + one;

        let candidate = Field::<CurrentEnvironment>::new(two);
        assert_eq!("2field", &format!("{candidate}"));
    }
}