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feat: allow if expressions for fallbacks in downcast macro #7322

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Merged
alamb merged 3 commits into from
Mar 25, 2025
Merged

feat: allow if expressions for fallbacks in downcast macro #7322

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9a5d08b
feat: allow if expressions for fallbacks in downcast macro
rluvaton Mar 23, 2025
ecdbe54
add examples of using this guards
rluvaton Mar 24, 2025
9ff8691
add examples of using this guards
rluvaton Mar 24, 2025
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128 changes: 83 additions & 45 deletions arrow-array/src/cast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,8 @@ macro_rules! repeat_pat {
/// k.as_ref() => (dictionary_key_size_helper, u8),
/// _ => unreachable!(),
/// },
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => u8::MAX,
/// _ => u8::MAX,
/// }
/// }
Expand All @@ -72,7 +74,7 @@ macro_rules! repeat_pat {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_integer {
($($data_type:expr),+ => ($m:path $(, $args:tt)*), $($p:pat => $fallback:expr $(,)*)*) => {
($($data_type:expr),+ => ($m:path $(, $args:tt)*), $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
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match ($($data_type),+) {
$crate::repeat_pat!($crate::cast::__private::DataType::Int8, $($data_type),+) => {
$m!($crate::types::Int8Type $(, $args)*)
Expand All @@ -98,7 +100,7 @@ macro_rules! downcast_integer {
$crate::repeat_pat!($crate::cast::__private::DataType::UInt64, $($data_type),+) => {
$m!($crate::types::UInt64Type $(, $args)*)
}
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
};
}
Expand All @@ -107,7 +109,7 @@ macro_rules! downcast_integer {
/// with the corresponding array, along with match statements for any non integer array types
///
/// ```
/// # use arrow_array::{Array, downcast_integer_array, cast::as_string_array};
/// # use arrow_array::{Array, downcast_integer_array, cast::as_string_array, cast::as_largestring_array};
/// # use arrow_schema::DataType;
///
/// fn print_integer(array: &dyn Array) {
Expand All @@ -122,6 +124,12 @@ macro_rules! downcast_integer {
/// println!("{:?}", v);
/// }
/// }
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => {
/// for v in as_largestring_array(array) {
/// println!("{:?}", v);
/// }
/// }
/// t => println!("Unsupported datatype {}", t)
/// )
/// }
Expand All @@ -130,19 +138,19 @@ macro_rules! downcast_integer {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_integer_array {
($values:ident => $e:expr, $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_integer_array!($values => {$e} $($p => $fallback)*)
($values:ident => $e:expr, $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_integer_array!($values => {$e} $($p $(if $pred)* => $fallback)*)
};
(($($values:ident),+) => $e:expr, $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_integer_array!($($values),+ => {$e} $($p => $fallback)*)
(($($values:ident),+) => $e:expr, $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_integer_array!($($values),+ => {$e} $($p $(if $pred)* => $fallback)*)
};
($($values:ident),+ => $e:block $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_integer_array!(($($values),+) => $e $($p => $fallback)*)
($($values:ident),+ => $e:block $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_integer_array!(($($values),+) => $e $($p $(if $pred)* => $fallback)*)
};
(($($values:ident),+) => $e:block $($p:pat => $fallback:expr $(,)*)*) => {
(($($values:ident),+) => $e:block $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_integer!{
$($values.data_type()),+ => ($crate::downcast_primitive_array_helper, $($values),+, $e),
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
};
}
Expand All @@ -167,6 +175,8 @@ macro_rules! downcast_integer_array {
/// k.data_type() => (run_end_size_helper, u8),
/// _ => unreachable!(),
/// },
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => u8::MAX,
/// _ => u8::MAX,
/// }
/// }
Expand All @@ -179,7 +189,7 @@ macro_rules! downcast_integer_array {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_run_end_index {
($($data_type:expr),+ => ($m:path $(, $args:tt)*), $($p:pat => $fallback:expr $(,)*)*) => {
($($data_type:expr),+ => ($m:path $(, $args:tt)*), $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
match ($($data_type),+) {
$crate::repeat_pat!($crate::cast::__private::DataType::Int16, $($data_type),+) => {
$m!($crate::types::Int16Type $(, $args)*)
Expand All @@ -190,7 +200,7 @@ macro_rules! downcast_run_end_index {
$crate::repeat_pat!($crate::cast::__private::DataType::Int64, $($data_type),+) => {
$m!($crate::types::Int64Type $(, $args)*)
}
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
};
}
Expand All @@ -211,6 +221,8 @@ macro_rules! downcast_run_end_index {
/// fn temporal_size(t: &DataType) -> u8 {
/// downcast_temporal! {
/// t => (temporal_size_helper, u8),
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => u8::MAX,
/// _ => u8::MAX
/// }
/// }
Expand All @@ -222,7 +234,7 @@ macro_rules! downcast_run_end_index {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_temporal {
($($data_type:expr),+ => ($m:path $(, $args:tt)*), $($p:pat => $fallback:expr $(,)*)*) => {
($($data_type:expr),+ => ($m:path $(, $args:tt)*), $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
match ($($data_type),+) {
$crate::repeat_pat!($crate::cast::__private::DataType::Time32($crate::cast::__private::TimeUnit::Second), $($data_type),+) => {
$m!($crate::types::Time32SecondType $(, $args)*)
Expand Down Expand Up @@ -254,7 +266,7 @@ macro_rules! downcast_temporal {
$crate::repeat_pat!($crate::cast::__private::DataType::Timestamp($crate::cast::__private::TimeUnit::Nanosecond, _), $($data_type),+) => {
$m!($crate::types::TimestampNanosecondType $(, $args)*)
}
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
};
}
Expand All @@ -263,7 +275,7 @@ macro_rules! downcast_temporal {
/// accepts a number of subsequent patterns to match the data type
///
/// ```
/// # use arrow_array::{Array, downcast_temporal_array, cast::as_string_array};
/// # use arrow_array::{Array, downcast_temporal_array, cast::as_string_array, cast::as_largestring_array};
/// # use arrow_schema::DataType;
///
/// fn print_temporal(array: &dyn Array) {
Expand All @@ -278,6 +290,12 @@ macro_rules! downcast_temporal {
/// println!("{:?}", v);
/// }
/// }
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => {
/// for v in as_largestring_array(array) {
/// println!("{:?}", v);
/// }
/// }
/// t => println!("Unsupported datatype {}", t)
/// )
/// }
Expand All @@ -286,19 +304,19 @@ macro_rules! downcast_temporal {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_temporal_array {
($values:ident => $e:expr, $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_temporal_array!($values => {$e} $($p => $fallback)*)
($values:ident => $e:expr, $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_temporal_array!($values => {$e} $($p $(if $pred)* => $fallback)*)
};
(($($values:ident),+) => $e:expr, $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_temporal_array!($($values),+ => {$e} $($p => $fallback)*)
(($($values:ident),+) => $e:expr, $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_temporal_array!($($values),+ => {$e} $($p $(if $pred)* => $fallback)*)
};
($($values:ident),+ => $e:block $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_temporal_array!(($($values),+) => $e $($p => $fallback)*)
($($values:ident),+ => $e:block $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_temporal_array!(($($values),+) => $e $($p $(if $pred)* => $fallback)*)
};
(($($values:ident),+) => $e:block $($p:pat => $fallback:expr $(,)*)*) => {
(($($values:ident),+) => $e:block $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_temporal!{
$($values.data_type()),+ => ($crate::downcast_primitive_array_helper, $($values),+, $e),
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
};
}
Expand All @@ -319,6 +337,8 @@ macro_rules! downcast_temporal_array {
/// fn primitive_size(t: &DataType) -> u8 {
/// downcast_primitive! {
/// t => (primitive_size_helper, u8),
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => u8::MAX,
/// _ => u8::MAX
/// }
/// }
Expand All @@ -333,7 +353,7 @@ macro_rules! downcast_temporal_array {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_primitive {
($($data_type:expr),+ => ($m:path $(, $args:tt)*), $($p:pat => $fallback:expr $(,)*)*) => {
($($data_type:expr),+ => ($m:path $(, $args:tt)*), $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_integer! {
$($data_type),+ => ($m $(, $args)*),
$crate::repeat_pat!($crate::cast::__private::DataType::Float16, $($data_type),+) => {
Expand Down Expand Up @@ -375,7 +395,7 @@ macro_rules! downcast_primitive {
_ => {
$crate::downcast_temporal! {
$($data_type),+ => ($m $(, $args)*),
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
}
}
Expand All @@ -395,7 +415,7 @@ macro_rules! downcast_primitive_array_helper {
/// accepts a number of subsequent patterns to match the data type
///
/// ```
/// # use arrow_array::{Array, downcast_primitive_array, cast::as_string_array};
/// # use arrow_array::{Array, downcast_primitive_array, cast::as_string_array, cast::as_largestring_array};
/// # use arrow_schema::DataType;
///
/// fn print_primitive(array: &dyn Array) {
Expand All @@ -410,6 +430,12 @@ macro_rules! downcast_primitive_array_helper {
/// println!("{:?}", v);
/// }
/// }
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => {
/// for v in as_largestring_array(array) {
/// println!("{:?}", v);
/// }
/// }
/// t => println!("Unsupported datatype {}", t)
/// )
/// }
Expand All @@ -418,19 +444,19 @@ macro_rules! downcast_primitive_array_helper {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_primitive_array {
($values:ident => $e:expr, $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_primitive_array!($values => {$e} $($p => $fallback)*)
($values:ident => $e:expr, $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_primitive_array!($values => {$e} $($p $(if $pred)* => $fallback)*)
};
(($($values:ident),+) => $e:expr, $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_primitive_array!($($values),+ => {$e} $($p => $fallback)*)
(($($values:ident),+) => $e:expr, $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_primitive_array!($($values),+ => {$e} $($p $(if $pred)* => $fallback)*)
};
($($values:ident),+ => $e:block $($p:pat => $fallback:expr $(,)*)*) => {
$crate::downcast_primitive_array!(($($values),+) => $e $($p => $fallback)*)
($($values:ident),+ => $e:block $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_primitive_array!(($($values),+) => $e $($p $(if $pred)* => $fallback)*)
};
(($($values:ident),+) => $e:block $($p:pat => $fallback:expr $(,)*)*) => {
(($($values:ident),+) => $e:block $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
$crate::downcast_primitive!{
$($values.data_type()),+ => ($crate::downcast_primitive_array_helper, $($values),+, $e),
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
};
}
Expand Down Expand Up @@ -482,7 +508,7 @@ macro_rules! downcast_dictionary_array_helper {
/// a number of subsequent patterns to match the data type
///
/// ```
/// # use arrow_array::{Array, StringArray, downcast_dictionary_array, cast::as_string_array};
/// # use arrow_array::{Array, StringArray, downcast_dictionary_array, cast::as_string_array, cast::as_largestring_array};
/// # use arrow_schema::DataType;
///
/// fn print_strings(array: &dyn Array) {
Expand All @@ -500,6 +526,12 @@ macro_rules! downcast_dictionary_array_helper {
/// println!("{:?}", v);
/// }
/// }
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => {
/// for v in as_largestring_array(array) {
/// println!("{:?}", v);
/// }
/// }
/// t => println!("Unsupported datatype {}", t)
/// )
/// }
Expand All @@ -508,19 +540,19 @@ macro_rules! downcast_dictionary_array_helper {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_dictionary_array {
($values:ident => $e:expr, $($p:pat => $fallback:expr $(,)*)*) => {
downcast_dictionary_array!($values => {$e} $($p => $fallback)*)
($values:ident => $e:expr, $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
downcast_dictionary_array!($values => {$e} $($p $(if $pred)* => $fallback)*)
};

($values:ident => $e:block $($p:pat => $fallback:expr $(,)*)*) => {
($values:ident => $e:block $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
match $values.data_type() {
$crate::cast::__private::DataType::Dictionary(k, _) => {
$crate::downcast_integer! {
k.as_ref() => ($crate::downcast_dictionary_array_helper, $values, $e),
k => unreachable!("unsupported dictionary key type: {}", k)
}
}
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
}
}
Expand Down Expand Up @@ -584,7 +616,7 @@ macro_rules! downcast_run_array_helper {
/// a number of subsequent patterns to match the data type
///
/// ```
/// # use arrow_array::{Array, StringArray, downcast_run_array, cast::as_string_array};
/// # use arrow_array::{Array, StringArray, downcast_run_array, cast::as_string_array, cast::as_largestring_array};
/// # use arrow_schema::DataType;
///
/// fn print_strings(array: &dyn Array) {
Expand All @@ -602,6 +634,12 @@ macro_rules! downcast_run_array_helper {
/// println!("{:?}", v);
/// }
/// }
/// // You can also add a guard to the pattern
/// DataType::LargeUtf8 if true => {
/// for v in as_largestring_array(array) {
/// println!("{:?}", v);
/// }
/// }
/// t => println!("Unsupported datatype {}", t)
/// )
/// }
Expand All @@ -610,19 +648,19 @@ macro_rules! downcast_run_array_helper {
/// [`DataType`]: arrow_schema::DataType
#[macro_export]
macro_rules! downcast_run_array {
($values:ident => $e:expr, $($p:pat => $fallback:expr $(,)*)*) => {
downcast_run_array!($values => {$e} $($p => $fallback)*)
($values:ident => $e:expr, $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
downcast_run_array!($values => {$e} $($p $(if $pred)* => $fallback)*)
};

($values:ident => $e:block $($p:pat => $fallback:expr $(,)*)*) => {
($values:ident => $e:block $($p:pat $(if $pred:expr)* => $fallback:expr $(,)*)*) => {
match $values.data_type() {
$crate::cast::__private::DataType::RunEndEncoded(k, _) => {
$crate::downcast_run_end_index! {
k.data_type() => ($crate::downcast_run_array_helper, $values, $e),
k => unreachable!("unsupported run end index type: {}", k)
}
}
$($p => $fallback,)*
$($p $(if $pred)* => $fallback,)*
}
}
}
Expand Down
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