proteus 0.5.0

Proteus is intended to make dynamic transformation of data using serde serializable, deserialize using JSON and a JSON transformation syntax similar to Javascript JSON syntax. It also supports registering custom Actions to be used in the syntax.
Documentation 
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

use crate::action::Action;
use crate::errors::Error;
use serde::{Deserialize, Serialize};
use serde_json::Value;
use std::borrow::Cow;

/// This type represents an [Action](../action/trait.Action.html) which returns a constant Value
/// instead of it originating from the source JSON data.
#[derive(Debug, Serialize, Deserialize)]
pub struct Constant {
    value: Value,
}

impl Constant {
    pub const fn new(value: Value) -> Self {
        Self { value }
    }
}

#[typetag::serde]
impl Action for Constant {
    fn apply<'a>(
        &'a self,
        _source: &'a Value,
        _destination: &mut Value,
    ) -> Result<Option<Cow<'a, Value>>, Error> {
        Ok(Some(Cow::Borrowed(&self.value)))
    }
}