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Added support for comprehensions over iterators over tuples. #10

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Added support for comprehensions over iterators over tuples. #10

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4679738
Accepting `pat` rather `than` ident in `for x` to allow tuples (e.g.,…
ElliotLockerman Dec 24, 2017
e126105
Fixed doc tests
ElliotLockerman Dec 24, 2017
27e5976
Added documentation for comprehensions over tuples
ElliotLockerman Dec 24, 2017
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125 changes: 102 additions & 23 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@
//! allowing for conditionals and nested comprehensions.
//!
//! # Python Syntax
//! ```
//! ```python
//! squares = [x*x for x in range(10)]
//!
//! even_squares = [x*x for x in range(10) if x % 2 == 0]
Expand All @@ -17,13 +17,13 @@
//! ```
//! #[macro_use(c)]
//! extern crate cute;
//!
//! # fn main() { // needed to include macro
//! let squares = c![x*x, for x in 0..10];
//!
//! let even_squares = c![x*x, for x in 0..10, if x % 2 == 0];
//!
//! let squares_hashmap = c!{key => key*key, for key in 0..10};
//!
//! # }
//! ```
//!
//! `c!`'s has the comprehension's parts, comma-separated.
Expand All @@ -33,66 +33,116 @@
//! Simple comprehension
//!
//! ```
//! let v = [1,2,3,4];
//! # #[macro_use(c)]
//! # extern crate cute;
//! # // otherwise its implicitly put in a function, so you can't `use`
//! # fn main() {
//! let v = vec![1,2,3,4];
//! let v_squared = c![x*x, for x in v];
//!
//! # }
//! ```
//! Conditional filtering
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # fn main() {
//! let squares = c![x*x, for x in 0..10, if x % 2 == 0];
//! assert_eq!(squares, vec![0, 4, 16, 36, 64]);
//! # }
//! ```
//!
//! Comprehensions over tuples
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # fn main() {
//! let v1 = vec![1, 2, 3];
//! let v2 = vec![10, 11, 12];
//! let sums = c![x+y, for (x,y) in v1.iter().zip(v2)];
//! assert_eq!(sums, vec![11, 13, 15]);
//! # }
//! ```
//!
//! Nested Comprehensions
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # fn main() {
//! let nested = vec![vec![1,2,3], vec![4,5,6], vec![7,8,9]];
//! let flat: Vec<usize> = c![x, for x in y, for y in nested];
//! assert_eq!(flat, vec![1, 2, 3, 4, 5, 6, 7, 8, 9]);
//! # }
//! ```
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # fn main() {
//! let nested = vec![vec![1,2,3], vec![4,5,6], vec![7,8,9]];
//! let even_flat: Vec<usize> = c![x, for x in y, for y in nested, if x % 2 == 0];
//! assert_eq!(even_flat, vec![2, 4, 6, 8]);
//! # }
//! ```
//!
//! Comprehensions over Iterators
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # fn main() {
//! let vec: Vec<i32> = vec![-4, -2, 0, 2, 4];
//! let output: Vec<i32> = c![x*2, for x in vec.iter()];
//! assert_eq!(output, vec![-8, -4, 0, 4, 8]);
//! # }
//! ```
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # fn main() {
//! let vec: Vec<i32> = vec![-4, -2, 0, 2, 4];
//! let output: Vec<i32> = c![x, for x in vec.iter(), if *x >= 0i32];
//! assert_eq!(output, vec![0, 2, 4]);
//! # }
//! ```
//!

//! Function Application
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # fn main() {
//! let vec: Vec<i32> = vec![-4, -2, 0, 2, 4];
//! let output: Vec<i32> = c![x.abs(), for x in vec.iter()];
//! assert_eq!(output, vec![4, 2, 0, 2, 4]);
//! # }
//! ```
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # fn main() {
//! fn square(x:i32) -> i32 {
//! x*x
//! }
//!
//! let vec: Vec<i32> = vec![-4, -2, 0, 2, 4];
//! let squares: Vec<i32> = c![square(x), for x in vec];
//! assert_eq!(squares, vec![16, 4, 0, 4, 16]);
//! # }
//! ```
//!
//! Hashmap Comprehensions
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # use std::collections::HashMap;
//! # fn main() {
//! let v = vec!["one", "two", "three"];
//! let map = c!{key => key.to_uppercase(), for key in v};
//!
Expand All @@ -102,9 +152,14 @@
//! expected.insert("three", String::from("THREE"));
//!
//! assert_eq!(map, expected);
//! # }
//! ```
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # use std::collections::HashMap;
//! # fn main() {
//! let v: Vec<(&str, i32)> = vec![("one", 1), ("two", 2), ("three", 3)];
//! let map = c!{key => val, for (key, val) in v};
//!
Expand All @@ -114,9 +169,14 @@
//! expected.insert("three", 3);
//!
//! assert_eq!(map, expected);
//! # }
//! ```
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # use std::collections::HashMap;
//! # fn main() {
//! // conditional hashmap comprehension
//! let v: Vec<(&str, i32)> = vec![("one", 1), ("two", 2), ("three", 3)];
//! let map = c! {key => val, for (key, val) in v, if val == 1 || val == 2};
Expand All @@ -126,35 +186,42 @@
//! expected.insert("two", 2);
//!
//! assert_eq!(map, expected);
//! # }
//! ```
//!
//! ```
//! # #[macro_use(c)]
//! # extern crate cute;
//! # use std::collections::HashMap;
//! # fn main() {
//! // conditional hashmap comprehension from an Iterator
//! let map = c! {*key => key*key, for key in vec![1,2].iter(), if *key % 2 == 0};
//! let mut e: HashMap<i32, i32> = HashMap::new();
//! e.insert(2, 4);
//!
//! assert_eq!(map, e);
//! # }
//! ```



#[macro_export]
macro_rules! c {

($exp:expr, for $i:ident in $iter:expr) => (
($exp:expr, for $p:pat in $iter:expr) => (
{
let mut r = vec![];
for $i in $iter {
for $p in $iter {
r.push($exp);
}
r
}
);

($exp:expr, for $i:ident in $iter:expr, if $cond:expr) => (
($exp:expr, for $p:pat in $iter:expr, if $cond:expr) => (
{
let mut r = vec![];
for $i in $iter {
for $p in $iter {
if $cond {
r.push($exp.clone());
}
Expand All @@ -163,23 +230,23 @@ macro_rules! c {
}
);

($exp:expr, for $i:ident in $iter:expr, for $i2:ident in $iter2:expr) => (
($exp:expr, for $p:pat in $iter:expr, for $p2:pat in $iter2:expr) => (
{
let mut r = vec![];
for $i2 in $iter2 {
for $i in $iter {
for $p2 in $iter2 {
for $p in $iter {
r.push($exp);
}
}
r
}
);

($exp:expr, for $i:ident in $iter:expr, for $i2:ident in $iter2:expr, if $cond:expr) => (
($exp:expr, for $p:pat in $iter:expr, for $p2:pat in $iter2:expr, if $cond:expr) => (
{
let mut r = vec![];
for $i2 in $iter2 {
for $i in $iter {
for $p2 in $iter2 {
for $p in $iter {
if $cond{
r.push($exp);
}
Expand All @@ -189,12 +256,12 @@ macro_rules! c {
}
);

($exp:expr, for $i:ident in $iter:expr, for $i2:ident in $iter2:expr, for $i3:ident in $iter3:expr, if $cond:expr) => (
($exp:expr, for $p:pat in $iter:expr, for $p2:pat in $iter2:expr, for $p3:pat in $iter3:expr, if $cond:expr) => (
{
let mut r = vec![];
for $i in $iter {
for $i2 in $iter2 {
for $i3 in $iter3 {
for $p in $iter {
for $p2 in $iter2 {
for $p3 in $iter3 {
if $cond {
r.push($exp);
}
Expand All @@ -205,12 +272,12 @@ macro_rules! c {
}
);

($exp:expr, for $i:ident in $iter:expr, for $i2:ident in $iter2:expr, for $i3:ident in $iter3:expr) => (
($exp:expr, for $p:pat in $iter:expr, for $p2:pat in $iter2:expr, for $p3:pat in $iter3:expr) => (
{
let mut r = vec![];
for $i in $iter {
for $i2 in $iter2 {
for $i3 in $iter3 {
for $p in $iter {
for $p2 in $iter2 {
for $p3 in $iter3 {
r.push($exp);
}
}
Expand Down Expand Up @@ -277,12 +344,24 @@ mod tests {
assert_eq!(squares, vec![0, 1, 4, 9, 16, 25, 36, 49, 64, 81]);
}

#[test]
fn tuple_comprehension() {
let pairs = c![(x,y), for (x, y) in (0..3).zip(100..103)];
assert_eq!(pairs, vec![(0, 100), (1, 101), (2, 102)]);
}

#[test]
fn filter_comprehension() {
let squares = c![x*x, for x in 0..10, if x % 2 == 0];
assert_eq!(squares, vec![0, 4, 16, 36, 64]);
}

#[test]
fn filter_tuple_comprehension() {
let matches = c![x, for (x,y) in vec![0,1,2].iter().zip(vec![0,3,2]), if x == &y];
assert_eq!(matches, vec![0, 2]);
}

#[test]
fn simple_nested_comprehension() {
let nested = vec![vec![1, 2, 3], vec![4, 5, 6], vec![7, 8, 9]];
Expand Down