csvsc 0.1.0

Build processing chains for CSV files
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
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47

use std::fmt::Debug;
use crate::{Headers, Row};

mod avg;
mod count;
mod default_max;
mod default_min;
mod default_sum;
mod last;
mod max;
mod min;
mod sum;

pub use avg::Avg;
pub use count::Count;
pub use default_max::DefaultMax;
pub use default_min::DefaultMin;
pub use default_sum::DefaultSum;
pub use last::Last;
pub use max::Max;
pub use min::Min;
pub use sum::Sum;

#[derive(Debug)]
pub enum AggregateError {
    /// Specified column does not exist
    MissingColumn(String),

    /// Could not parse value to required type
    ValueError {
        row: Row,
        index: usize,
        aggregate: String,
    },
}

/// Aggregates used while reducing must implement this trait.
pub trait Aggregate: Debug {
    /// Updates the current value with the next row of data.
    fn update(&mut self, headers: &Headers, row: &Row) -> Result<(), AggregateError>;

    /// Gets the current value.
    fn value(&self) -> String;

    /// Gets this aggregate's colname
    fn colname(&self) -> &str;
}