use std::rc;
use time;
use expression;
use field;
use sql;
macro_rules! agg_func {
($foo:ident, $foo_arg:ident, $foo_low:ident) => (
pub trait $foo_arg<R: Clone, T: Clone>: Clone + expression::Expression<T> + 'static {
fn $foo_low(&self) -> $foo<R, T, Self> {
$foo::new(self.clone())
}
}
#[derive(Clone)]
pub struct $foo<R, T, E: $foo_arg<R, T>> {
pub expression: E
}
#[allow(dead_code)]
impl<R: Clone, T: Clone, E: $foo_arg<R, T> + 'static> $foo<R, T, E> {
pub fn new(expr: E) -> $foo<R, T, E> {
$foo {
expression: expr.clone()
}
}
}
impl<R: Clone, T: Clone, E: $foo_arg<R, T> + 'static> expression::UntypedExpression for $foo<R, T, E> {
fn expression_as_sql(&self) -> &sql::ToSql {
self
}
fn upcast_expression(&self) -> expression::SharedExpression {
rc::Rc::new(Box::new(self.clone()) as expression::BoxedExpression)
}
}
impl<R: Clone, T: Clone, E: $foo_arg<R, T> + 'static> expression::Expression<R> for $foo<R, T, E> { }
)
}
agg_func!(Min, MinArg, min);
impl MinArg<i8, i8> for field::I8Field {}
impl MinArg<i16, i16> for field::I16Field {}
impl MinArg<i32, i32> for field::I32Field {}
impl MinArg<i64, i64> for field::I64Field {}
impl MinArg<f32, f32> for field::F32Field {}
impl MinArg<f64, f64> for field::F64Field {}
impl MinArg<String, String> for field::StringField {}
impl MinArg<time::Timespec, time::Timespec> for field::TimespecField {}
agg_func!(Max, MaxArg, max);
impl MaxArg<i8, i8> for field::I8Field {}
impl MaxArg<i16, i16> for field::I16Field {}
impl MaxArg<i32, i32> for field::I32Field {}
impl MaxArg<i64, i64> for field::I64Field {}
impl MaxArg<f32, f32> for field::F32Field {}
impl MaxArg<f64, f64> for field::F64Field {}
impl MaxArg<String, String> for field::StringField {}
impl MaxArg<time::Timespec, time::Timespec> for field::TimespecField {}
agg_func!(Sum, SumArg, sum);
impl SumArg<i64, i8> for field::I8Field {}
impl SumArg<i64, i16> for field::I16Field {}
impl SumArg<i64, i32> for field::I32Field {}
impl SumArg<i64, i64> for field::I64Field {}
impl SumArg<f64, f32> for field::F32Field {}
impl SumArg<f64, f64> for field::F64Field {}
agg_func!(Avg, AvgArg, avg);
impl AvgArg<i8, i8> for field::I8Field {}
impl AvgArg<i16, i16> for field::I16Field {}
impl AvgArg<i32, i32> for field::I32Field {}
impl AvgArg<i64, i64> for field::I64Field {}
impl AvgArg<f32, f32> for field::F32Field {}
impl AvgArg<f64, f64> for field::F64Field {}
agg_func!(Count, CountArg, count);
impl<T: expression::PrimitiveType + Clone> CountArg<i64, T> for field::NamedField<T> {}
#[derive(Clone, Copy)]
pub struct CountAll;
impl expression::UntypedExpression for CountAll {
fn expression_as_sql(&self) -> &sql::ToSql {
self
}
fn upcast_expression(&self) -> expression::SharedExpression {
rc::Rc::new(Box::new(self.clone()) as expression::BoxedExpression)
}
}
impl expression::Expression<i64> for CountAll { }