src/read.rs


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

use serde::{Deserialize, Serialize};
use std::convert::TryInto;

use crate::error::*;
use crate::tokenizer::tokenize_with_seperator;
use crate::object::*;
use crate::tokenizer::Token;
use crate::query::Query;

pub trait Read<'doc> : Object<'doc> + Sized {
    fn read(&'doc self, query: &Query) -> Result<Option<&'doc Self>> {
        //match query_with_token(self, query.token())? {
        //    None    => Ok(None),
        //    Some(o) => Ok(Some(o.as_deserialize())),
        //}
        unimplemented!()
    }
}

#[cfg(feature = "backend_toml")]
impl<'doc> Read<'doc> for toml::Value { }

#[cfg(feature = "backend_serde_json")]
impl<'doc> Read<'doc> for serde_json::Value { }

fn query_with_token<'doc, O>(obj: &'doc O, token: &Token) -> Result<Option<&'doc O>>
    where O: Object<'doc>
{
    match token {
        Token::Identifier{ ident, .. } => {
            let object = obj.at_key(ident)?;
            if let Some(object) = object {
                if let Some(next_token) = token.next() {
                    query_with_token(object, next_token)
                } else {
                    Ok(Some(object))
                }
            } else {
                Ok(None)
            }
        }

        Token::Index { idx, .. } => {
            let object = obj.at_index(*idx)?;
            if let Some(object) = object {
                if let Some(next_token) = token.next() {
                    query_with_token(object, next_token)
                } else {
                    Ok(Some(object))
                }
            } else {
                Ok(None)
            }
        }
    }
}