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
143

use std::{
    collections::BTreeSet,
    ops::{Bound, RangeBounds},
};

/// Object helps to locate a nessesary part of a `Grid`.
pub trait Object: Sized {
    /// Cells returns a set of cordinates of cells
    fn cells(&self, count_rows: usize, count_columns: usize) -> Vec<(usize, usize)>;

    /// And combines output of self with rhs object
    fn and<O: Object>(self, rhs: O) -> Combination<Self, O> {
        Combination {
            lhs: self,
            rhs,
            combinator: combine_cells,
        }
    }

    /// Not excludes output of rhs from output
    fn not<O: Object>(self, rhs: O) -> Combination<Self, O> {
        Combination {
            lhs: self,
            rhs,
            combinator: remove_cells,
        }
    }
}

/// Head represent a row with column names
pub struct Head;

impl Object for Head {
    fn cells(&self, _: usize, count_columns: usize) -> Vec<(usize, usize)> {
        (0..count_columns).map(|column| (0, column)).collect()
    }
}

/// Head represent all cells on a `Grid`
pub struct Full;

impl Object for Full {
    fn cells(&self, count_rows: usize, count_columns: usize) -> Vec<(usize, usize)> {
        (0..count_rows)
            .map(|row| {
                (0..count_columns)
                    .map(|column| (row, column))
                    .collect::<Vec<_>>()
            })
            .collect::<Vec<_>>()
            .concat()
    }
}

/// Row denotes a set of cells on given rows on a `Grid`
pub struct Row<R: RangeBounds<usize>>(pub R);

impl<R: RangeBounds<usize>> Object for Row<R> {
    fn cells(&self, count_rows: usize, count_columns: usize) -> Vec<(usize, usize)> {
        let (x, y) = bounds_to_usize(self.0.start_bound(), self.0.end_bound(), count_rows);

        (x..y)
            .map(|row| (0..count_columns).map(|column| (row, column)).collect())
            .collect::<Vec<Vec<_>>>()
            .concat()
    }
}

/// Column denotes a set of cells on given columns on a `Grid`
pub struct Column<R: RangeBounds<usize>>(pub R);

impl<R: RangeBounds<usize>> Object for Column<R> {
    fn cells(&self, count_rows: usize, count_columns: usize) -> Vec<(usize, usize)> {
        let (x, y) = bounds_to_usize(self.0.start_bound(), self.0.end_bound(), count_columns);

        (x..y)
            .map(|column| (0..count_rows).map(|row| (row, column)).collect())
            .collect::<Vec<Vec<_>>>()
            .concat()
    }
}

/// Cell denotes a particular of cells on a `Grid`
pub struct Cell(pub usize, pub usize);

impl Object for Cell {
    fn cells(&self, _: usize, _: usize) -> Vec<(usize, usize)> {
        vec![(self.0, self.1)]
    }
}

type Combinator = fn(Vec<(usize, usize)>, Vec<(usize, usize)>) -> Vec<(usize, usize)>;

/// Combination struct which allows a chain of objects
pub struct Combination<L, R> {
    lhs: L,
    rhs: R,
    combinator: Combinator,
}

impl<L, R> Object for Combination<L, R>
where
    L: Object,
    R: Object,
{
    fn cells(&self, count_rows: usize, count_columns: usize) -> Vec<(usize, usize)> {
        let l = self.lhs.cells(count_rows, count_columns);
        let r = self.rhs.cells(count_rows, count_columns);
        (self.combinator)(l, r)
    }
}

fn combine_cells(lhs: Vec<(usize, usize)>, rhs: Vec<(usize, usize)>) -> Vec<(usize, usize)> {
    lhs.into_iter()
        .chain(rhs.into_iter())
        .collect::<BTreeSet<_>>()
        .into_iter()
        .collect()
}

fn remove_cells(lhs: Vec<(usize, usize)>, rhs: Vec<(usize, usize)>) -> Vec<(usize, usize)> {
    lhs.into_iter().filter(|l| !rhs.contains(l)).collect()
}

pub(crate) fn bounds_to_usize(
    left: Bound<&usize>,
    right: Bound<&usize>,
    count_elements: usize,
) -> (usize, usize) {
    match (left, right) {
        (Bound::Included(x), Bound::Included(y)) => (*x, y + 1),
        (Bound::Included(x), Bound::Excluded(y)) => (*x, *y),
        (Bound::Included(x), Bound::Unbounded) => (*x, count_elements),
        (Bound::Unbounded, Bound::Unbounded) => (0, count_elements),
        (Bound::Unbounded, Bound::Included(y)) => (0, y + 1),
        (Bound::Unbounded, Bound::Excluded(y)) => (0, *y),
        (Bound::Excluded(_), Bound::Unbounded)
        | (Bound::Excluded(_), Bound::Included(_))
        | (Bound::Excluded(_), Bound::Excluded(_)) => {
            unreachable!("A start bound can't be excluded")
        }
    }
}