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Merge pull request #681 from fabriziosestito/array-find

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Add array find and find_map methods
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Stephen Chung 2022-12-20 22:18:48 +08:00 committed by GitHub
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142
src/packages/array_basic.rs
View File

@ -2257,4 +2257,146 @@ pub mod array_functions {
) -> RhaiResultOf<bool> {
equals(ctx, array1, array2).map(|r| !r)
}
/// Iterate through all the elements in the array, applying a `filter` function to each element
/// in turn, and return a copy of the first element that returns `true`.
/// If no element returns `true`, `()` is returned.
///
/// # Function Parameters
///
/// * `element`: copy of array element
/// * `index` _(optional)_: current index in the array
///
/// # Example
///
/// ```rhai
/// let x = [1, 2, 3, 5, 8, 13];
///
/// print(x.find(|v| v > 3)); // prints 5: 5 > 3
///
/// x.find(|v| v > 13) ?? print("not found"); // prints "not found": nothing is > 13
///
/// print(x.find(|v, i| v * i > 13)); // prints 5: 3 * 5 > 13
/// ```
#[rhai_fn(return_raw, pure)]
pub fn find(ctx: NativeCallContext, array: &mut Array, filter: FnPtr) -> RhaiResult {
find_starting_from(ctx, array, filter, 0)
}
/// Iterate through all the elements in the array, starting from a particular `start` position,
/// applying a `filter` function to each element in turn, and return a copy of the first
/// element that returns `true`. If no element returns `true`, `()` is returned.
///
/// * If `start` < 0, position counts from the end of the array (`-1` is the last element).
/// * If `start` < -length of array, position counts from the beginning of the array.
/// * If `start` ≥ length of array, `-1` is returned.
///
/// # Function Parameters
///
/// * `element`: copy of array element
/// * `index` _(optional)_: current index in the array
///
/// # Example
///
/// ```rhai
/// let x = [1, 2, 3, 5, 8, 13];
///
/// print(x.find(|v| v > 1, 2)); // prints 3: 3 > 1
///
/// x.find(|v| v < 2, 3) ?? print("not found"); // prints "not found": nothing < 2 past index 3
///
/// x.find(|v| v > 1, 8) ?? print("not found"); // prints "not found": nothing found past end of array
///
/// print(x.find(|v| v > 1, -3)); // prints 5: -3 = start from index 4
///
/// print(x.find(|v| v > 0, -99)); // prints 1: -99 = start from beginning
///
/// print(x.find(|v, i| v * i > 6, 3)); // prints 5: 5 * 4 > 6
/// ```
#[rhai_fn(name = "find", return_raw, pure)]
pub fn find_starting_from(
ctx: NativeCallContext,
array: &mut Array,
filter: FnPtr,
start: INT,
) -> RhaiResult {
let index = index_of_filter_starting_from(ctx, array, filter, start)?;
if index < 0 {
return Ok(Dynamic::UNIT);
}
Ok(get(array, index))
}
/// Iterate through all the elements in the array, applying a `mapper` function to each element
/// in turn, and return the first result that is not `()`.
/// If no result is not `()`, `()` is returned.
///
/// # Function Parameters
///
/// * `element`: copy of array element
/// * `index` _(optional)_: current index in the array
///
/// # Example
///
/// ```rhai
/// let x = [#{alice: 1}, #{bob: 2}, #{clara: 3}];
///
/// print(x.find_map(|v| v.alice)); // prints 1
///
/// x.find_map(|v| v.dave) ?? print("not found"); // prints "not found"
/// ```
#[rhai_fn(return_raw, pure)]
pub fn find_map(ctx: NativeCallContext, array: &mut Array, filter: FnPtr) -> RhaiResult {
find_map_starting_from(ctx, array, filter, 0)
}
/// Iterate through all the elements in the array, starting from a particular `start` position,
/// applying a `mapper` function to each element in turn, and return the first result that is not `()`.
/// If no result is not `()`, `()` is returned.
///
/// * If `start` < 0, position counts from the end of the array (`-1` is the last element).
/// * If `start` < -length of array, position counts from the beginning of the array.
/// * If `start` ≥ length of array, `-1` is returned.
///
/// # Function Parameters
///
/// * `element`: copy of array element
/// * `index` _(optional)_: current index in the array
///
/// # Example
///
/// ```rhai
/// let x = [#{alice: 1}, #{bob: 2}, #{bob: 3}, #{clara: 3}, #{alice: 0}, #{clara: 5}];
///
/// print(x.find_map(|v| v.alice, 2)); // prints 0
///
/// x.find_map(|v| v.bob, 4) ?? print("not found"); // prints "not found"
///
/// x.find_map(|v| v.alice, 8) ?? print("not found"); // prints "not found"
///
/// print(x.find_map(|v| v.bob, -4)); // prints 3: -4 = start from index 2
///
/// print(x.find_map(|v| v.alice, -99)); // prints 1: -99 = start from beginning
/// ```
#[rhai_fn(name = "find_map", return_raw, pure)]
pub fn find_map_starting_from(
ctx: NativeCallContext,
array: &mut Array,
filter: FnPtr,
start: INT,
) -> RhaiResult {
if array.is_empty() {
return Ok(Dynamic::UNIT);
}
let (start, ..) = calc_offset_len(array.len(), start, 0);
for (i, item) in array.iter().enumerate().skip(start) {
let value = make_dual_arity_fn_ptr_call("find_map", &filter, &ctx, [item.clone()], i)?;
if !value.is_unit() {
return Ok(value);
}
}
Ok(Dynamic::UNIT)
}
}

50
tests/arrays.rs
View File

@ -423,6 +423,56 @@ fn test_arrays_map_reduce() -> Result<(), Box<EvalAltResult>> {
"
)?);
assert_eq!(
engine.eval::<INT>(
"
let x = [1, 2, 3];
x.find(|v| v > 2)
"
)?,
3
);
assert_eq!(
engine.eval::<INT>(
"
let x = [1, 2, 3];
x.find(|v, i| v * i == 6)
"
)?,
3
);
assert_eq!(
engine.eval::<()>(
"
let x = [1, 2, 3, 2, 1];
x.find(|v| v > 4)
"
)?,
()
);
assert_eq!(
engine.eval::<INT>(
"
let x = [#{alice: 1}, #{bob: 2}, #{clara: 3}];
x.find_map(|v| v.bob)
"
)?,
2
);
assert_eq!(
engine.eval::<()>(
"
let x = [#{alice: 1}, #{bob: 2}, #{clara: 3}];
x.find_map(|v| v.dave)
"
)?,
()
);
Ok(())
}