agg: add product struct

Cargo.toml

@@ -28,7 +28,7 @@ maintenance = { status = "actively-developed" }
 
 [[example]]
 name = "calc"
-required-features = ["structs"]
+required-features = ["structs", "aggs"]
 
 [[example]]
 name = "dotenv"

examples/calc.rs

@@ -1,14 +1,12 @@
-use estring::{EString, SepVec};
+use estring::{Aggregate, EString, Product, SepVec, Sum};
 
 type PlusVec<T> = SepVec<T, '+'>;
 type MulVec<T> = SepVec<T, '*'>;
 
 fn main() -> estring::Result<()> {
     let res = EString::from("10+5*2+3")
-        .parse::<PlusVec<MulVec<f32>>>()?
-        .iter()
-        .map(|m| m.iter().product::<f32>())
-        .sum::<f32>();
+        .parse::<Sum<PlusVec<Product<MulVec<f32>>>>>()?
+        .agg();
 
     assert_eq!(res, 23.0);
     Ok(())

src/agg.rs

@@ -1,6 +1,8 @@
 //! This module will contain aggregate functions (Sum, Product, etc)
 //!
 
+mod product;
 mod sum;
 
+pub use product::*;
 pub use sum::*;

src/agg/product.rs

@@ -0,0 +1,92 @@
+use crate::{Aggregatable, Aggregate, EString, ParseFragment};
+
+/// Aggregate struct, that can multiply inner aggregatable [items](Aggregatable::items) if
+/// [``Aggregatable::Item``] implements [``std::iter::Product``](std::iter::Product)
+///
+/// # Examples
+///
+/// ```rust
+/// use estring::{Aggregate, EString, SepVec, Product};
+/// let res = EString::from("1*2*3*4")
+///     .parse::<Product<SepVec<i32, '*'>>>()
+///     .unwrap()
+///     .agg();
+/// assert_eq!(res, 24);
+/// ```
+#[derive(Debug, PartialEq, Eq)]
+pub struct Product<T>(pub T);
+
+impl<T> ParseFragment for Product<T>
+where
+    T: ParseFragment,
+{
+    fn parse_frag(es: EString) -> crate::Result<Self> {
+        T::parse_frag(es).map(Self)
+    }
+}
+
+impl<R, T> Aggregate for Product<T>
+where
+    R: std::iter::Product,
+    T: Aggregatable<Item = R>,
+{
+    type Target = R;
+
+    fn agg(self) -> Self::Target {
+        self.0.items().into_iter().product()
+    }
+}
+
+impl<R, T> Aggregatable for Product<T>
+where
+    R: std::iter::Product,
+    T: Aggregatable<Item = R>,
+{
+    type Item = R;
+
+    fn items(self) -> Vec<Self::Item> {
+        vec![self.agg()]
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::SepVec;
+
+    use super::*;
+
+    type CommaVec<T> = SepVec<T, ','>;
+    type MulVec<T> = SepVec<T, '*'>;
+
+    #[test]
+    fn should_parse_vec() {
+        let es = EString::from("1,2,3");
+        match es.parse::<Product<CommaVec<i32>>>() {
+            Ok(res) => assert_eq!(res, Product(CommaVec::from(vec![1, 2, 3]))),
+            _ => unreachable!(),
+        }
+    }
+
+    #[test]
+    fn should_aggregate_vector() {
+        let es = EString::from("1,2,3");
+        let expr = es.parse::<Product<CommaVec<i32>>>().unwrap();
+        assert_eq!(expr.agg(), 6);
+    }
+
+    #[test]
+    fn should_aggregate_vector_with_inner_vector() {
+        let es = EString::from("1*2,2,3");
+        let expr = es.parse::<Product<CommaVec<MulVec<i32>>>>().unwrap();
+        assert_eq!(expr.agg(), 12);
+    }
+
+    #[test]
+    fn should_aggregate_vector_with_inner_aggregation() {
+        let es = EString::from("1*2,2,3");
+        let expr = es
+            .parse::<Product<CommaVec<Product<MulVec<i32>>>>>()
+            .unwrap();
+        assert_eq!(expr.agg(), 12);
+    }
+}

src/agg/sum.rs

@@ -1,26 +1,31 @@
-use std::marker::PhantomData;
-
 use crate::{Aggregatable, Aggregate, EString, ParseFragment};
 
+/// Aggregate struct, that can sum inner aggregatable [items](Aggregatable::items) if
+/// [``Aggregatable::Item``] implements [``std::iter::Sum``](std::iter::Sum)
+///
+/// # Examples
+///
+/// ```rust
+/// use estring::{Aggregate, EString, SepVec, Sum};
+/// let res = EString::from("1+2+3+4")
+///     .parse::<Sum<SepVec<i32, '+'>>>()
+///     .unwrap()
+///     .agg();
+/// assert_eq!(res, 10);
+/// ```
 #[derive(Debug, PartialEq, Eq)]
-struct Sum<R, T>(T, PhantomData<R>);
+pub struct Sum<T>(pub T);
 
-impl<R, T> Sum<R, T> {
-    fn new(inner: T) -> Self {
-        Self(inner, PhantomData::default())
-    }
-}
-
-impl<R, T> ParseFragment for Sum<R, T>
+impl<T> ParseFragment for Sum<T>
 where
     T: ParseFragment,
 {
     fn parse_frag(es: EString) -> crate::Result<Self> {
-        T::parse_frag(es).map(Self::new)
+        T::parse_frag(es).map(Self)
     }
 }
 
-impl<R, T> Aggregate for Sum<R, T>
+impl<R, T> Aggregate for Sum<T>
 where
     R: std::iter::Sum,
     T: Aggregatable<Item = R>,
@@ -32,7 +37,7 @@ where
     }
 }
 
-impl<R, T> Aggregatable for Sum<R, T>
+impl<R, T> Aggregatable for Sum<T>
 where
     R: std::iter::Sum,
     T: Aggregatable<Item = R>,
@@ -56,8 +61,8 @@ mod tests {
     #[test]
     fn should_parse_vec() {
         let es = EString::from("1,2,3");
-        match es.parse::<Sum<i32, CommaVec<i32>>>() {
-            Ok(res) => assert_eq!(res, Sum::new(CommaVec::from(vec![1, 2, 3]))),
+        match es.parse::<Sum<CommaVec<i32>>>() {
+            Ok(res) => assert_eq!(res, Sum(CommaVec::from(vec![1, 2, 3]))),
             _ => unreachable!(),
         }
     }
@@ -65,23 +70,21 @@ mod tests {
     #[test]
     fn should_aggregate_vector() {
         let es = EString::from("1,2,3");
-        let expr = es.parse::<Sum<i32, CommaVec<i32>>>().unwrap();
+        let expr = es.parse::<Sum<CommaVec<i32>>>().unwrap();
         assert_eq!(expr.agg(), 6);
     }
 
     #[test]
     fn should_aggregate_vector_with_inner_vector() {
         let es = EString::from("1+2,2,3");
-        let expr = es.parse::<Sum<i32, CommaVec<PlusVec<i32>>>>().unwrap();
+        let expr = es.parse::<Sum<CommaVec<PlusVec<i32>>>>().unwrap();
         assert_eq!(expr.agg(), 8);
     }
 
     #[test]
     fn should_aggregate_vector_with_inner_aggregation() {
         let es = EString::from("1+2,2,3");
-        let expr = es
-            .parse::<Sum<_, CommaVec<Sum<_, PlusVec<i32>>>>>()
-            .unwrap();
+        let expr = es.parse::<Sum<CommaVec<Sum<PlusVec<i32>>>>>().unwrap();
         assert_eq!(expr.agg(), 8);
     }
 }