Struct CostModel 

pub struct CostModel { /* private fields */ }

Costs of the four edit operations.

Built for a keyboard Layout with CostModel::for_layout (CostModel::qwerty is the default). The layout only decides which substitutions are cheap; the minimum costs the search bounds use (c_min, c_indel_min, c_transpose_min) do not depend on it.

Implementations

impl CostModel

pub fn qwerty() -> Self

The default model with a QWERTY keyboard. Same as CostModel::for_layout(Layout::Qwerty).

pub fn for_layout(layout: Layout) -> Self

A model whose cheap substitutions are the neighbouring keys of layout (Layout::are_neighbours); see Layout for what the geometry leaves out. Every other pair of characters costs an ordinary substitution. Does not panic.

Examples

use keyhammer::cost::{CostModel, Layout};

let qwerty = CostModel::for_layout(Layout::Qwerty);
let azerty = CostModel::for_layout(Layout::Azerty);
// q and z touch on AZERTY, not on QWERTY.
assert_eq!(azerty.sub_cost(b'q', b'z', 1), 8);
assert_eq!(qwerty.sub_cost(b'q', b'z', 1), 16);
// m is next to n on QWERTY only.
assert_eq!(qwerty.sub_cost(b'm', b'n', 1), 8);
assert_eq!(azerty.sub_cost(b'm', b'n', 1), 16);
// ABNT2 has the QWERTY letters, and ç next to l and p.
let abnt2 = CostModel::for_layout(Layout::Abnt2);
assert_eq!(abnt2.sub_cost('ç', 'l', 1), 8);
assert_eq!(qwerty.sub_cost('ç', 'l', 1), 16);
assert_eq!(abnt2.sub_cost('a', 's', 1), qwerty.sub_cost('a', 's', 1));

pub fn sub_cost<S: Into<u32>>(&self, q: S, t: S, qpos: usize) -> Cost

Cost of typing q where the term has t; qpos is the index of q in the query.

Symbols are Unicode scalar values: a u8 is read as U+0000 to U+00FF, a char or a u32 as itself.

pub fn del_cost<S: PartialEq>(&self, q: &[S], qpos: usize) -> Cost

Cost of deleting the query symbol at qpos (the user typed an extra one).

pub fn ins_cost<S: PartialEq>( &self, t: S, prev_t: Option<S>, qpos: usize, ) -> Cost

Cost of inserting term symbol t (the user skipped it) when qpos query symbols are consumed.

pub fn transpose_cost(&self, qpos: usize) -> Cost

Cost of swapping two adjacent symbols, the first at qpos in the query.

pub fn c_min(&self) -> Cost

Smallest cost of any single edit.

pub fn c_indel_min(&self) -> Cost

Smallest cost of an insertion or deletion.

pub fn c_transpose_min(&self) -> Cost

Smallest cost of a transposition.

Trait Implementations

impl Clone for CostModel

fn clone(&self) -> CostModel

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CostModel

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for CostModel

impl PartialEq for CostModel

fn eq(&self, other: &CostModel) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for CostModel