mirror of https://github.com/rust-lang/rust
284 lines
8.1 KiB
Rust
284 lines
8.1 KiB
Rust
//@ run-pass
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#![feature(macro_metavar_expr)]
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fn main() {
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macro_rules! one_nested_count_and_len {
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( $( [ $( $l:literal ),* ] ),* ) => {
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[
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// outer-most repetition
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$(
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// inner-most repetition
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$(
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${ignore($l)} ${index()}, ${len()},
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)*
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${count($l)}, ${index()}, ${len()},
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)*
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${count($l)},
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]
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};
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}
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assert_eq!(
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one_nested_count_and_len!(["foo"], ["bar", "baz"]),
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[
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// # ["foo"]
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// ## inner-most repetition (first iteration)
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//
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// `index` is 0 because this is the first inner-most iteration.
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// `len` is 1 because there is only one inner-most repetition, "foo".
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0, 1,
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// ## outer-most repetition (first iteration)
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//
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// `count` is 1 because of "foo", i,e, `$l` has only one repetition,
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// `index` is 0 because this is the first outer-most iteration.
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// `len` is 2 because there are 2 outer-most repetitions, ["foo"] and ["bar", "baz"]
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1, 0, 2,
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// # ["bar", "baz"]
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// ## inner-most repetition (first iteration)
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//
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// `index` is 0 because this is the first inner-most iteration
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// `len` is 2 because there are repetitions, "bar" and "baz"
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0, 2,
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// ## inner-most repetition (second iteration)
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//
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// `index` is 1 because this is the second inner-most iteration
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// `len` is 2 because there are repetitions, "bar" and "baz"
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1, 2,
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// ## outer-most repetition (second iteration)
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//
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// `count` is 2 because of "bar" and "baz", i,e, `$l` has two repetitions,
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// `index` is 1 because this is the second outer-most iteration
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// `len` is 2 because there are 2 outer-most repetitions, ["foo"] and ["bar", "baz"]
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2, 1, 2,
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// # last count
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// Because there are a total of 3 repetitions of `$l`, "foo", "bar" and "baz"
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3,
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]
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);
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// Based on the above explanation, the following macros should be straightforward
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// Grouped from the outer-most to the inner-most
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macro_rules! three_nested_count {
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( $( { $( [ $( ( $( $i:ident )* ) )* ] )* } )* ) => {
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&[
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$( $( $(
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&[
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${ignore($i)} ${count($i, 0)},
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][..],
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)* )* )*
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$( $(
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&[
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${ignore($i)} ${count($i, 0)},
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${ignore($i)} ${count($i, 1)},
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][..],
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)* )*
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$(
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&[
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${ignore($i)} ${count($i, 0)},
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${ignore($i)} ${count($i, 1)},
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${ignore($i)} ${count($i, 2)},
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][..],
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)*
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&[
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${count($i, 0)},
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${count($i, 1)},
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${count($i, 2)},
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${count($i, 3)},
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][..]
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][..]
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}
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}
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assert_eq!(
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three_nested_count!(
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{
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[ (a b c) (d e f) ]
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[ (g h) (i j k l m) ]
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[ (n) ]
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}
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{
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[ (o) (p q) (r s) ]
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[ (t u v w x y z) ]
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}
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),
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&[
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// a b c
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&[3][..],
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// d e f
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&[3][..],
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// g h
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&[2][..],
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// i j k l m
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&[5][..],
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// n
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&[1][..],
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// o
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&[1][..],
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// p q
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&[2][..],
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// r s
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&[2][..],
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// t u v w x y z
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&[7][..],
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// (a b c) (d e f)
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&[6, 2][..],
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// (g h) (i j k l m)
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&[7, 2][..],
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// (n)
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&[1, 1][..],
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// (o) (p q) (r s)
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&[5, 3][..],
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// (t u v w x y z)
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&[7, 1][..],
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// [ (a b c) (d e f) ]
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// [ (g h) (i j k l m) ]
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// [ (n) ]
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&[14, 5, 3][..],
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// [ (o) (p q) (r s) ]
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// [ (t u v w x y z) ]
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&[12, 4, 2][..],
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// {
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// [ (a b c) (d e f) ]
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// [ (g h) (i j k l m) ]
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// [ (n) ]
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// }
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// {
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// [ (o) (p q) (r s) ]
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// [ (t u v w x y z) ]
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// }
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&[26, 9, 5, 2][..]
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][..]
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);
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// Grouped from the outer-most to the inner-most
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macro_rules! three_nested_len {
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( $( { $( [ $( ( $( $i:ident )* ) )* ] )* } )* ) => {
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&[
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$( $( $( $(
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&[
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${ignore($i)} ${len(3)},
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${ignore($i)} ${len(2)},
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${ignore($i)} ${len(1)},
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${ignore($i)} ${len(0)},
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][..],
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)* )* )* )*
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$( $( $(
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&[
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${ignore($i)} ${len(2)},
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${ignore($i)} ${len(1)},
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${ignore($i)} ${len(0)},
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][..],
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)* )* )*
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$( $(
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&[
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${ignore($i)} ${len(1)},
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${ignore($i)} ${len(0)},
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][..],
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)* )*
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$(
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&[
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${ignore($i)} ${len(0)},
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][..],
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)*
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][..]
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}
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}
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assert_eq!(
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three_nested_len!(
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{
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[ (a b c) (d e f) ]
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[ (g h) (i j k l m) ]
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[ (n) ]
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}
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{
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[ (o) (p q) (r s) ]
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[ (t u v w x y z) ]
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}
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),
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&[
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// a b c
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&[2, 3, 2, 3][..],
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&[2, 3, 2, 3][..],
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&[2, 3, 2, 3][..],
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// d e f
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&[2, 3, 2, 3][..],
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&[2, 3, 2, 3][..],
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&[2, 3, 2, 3][..],
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// g h
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&[2, 3, 2, 2][..],
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&[2, 3, 2, 2][..],
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// i j k l m
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&[2, 3, 2, 5][..],
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&[2, 3, 2, 5][..],
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&[2, 3, 2, 5][..],
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&[2, 3, 2, 5][..],
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&[2, 3, 2, 5][..],
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// n
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&[2, 3, 1, 1][..],
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// o
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&[2, 2, 3, 1][..],
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// p q
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&[2, 2, 3, 2][..],
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&[2, 2, 3, 2][..],
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// r s
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&[2, 2, 3, 2][..],
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&[2, 2, 3, 2][..],
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// t u v w x y z
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&[2, 2, 1, 7][..],
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&[2, 2, 1, 7][..],
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&[2, 2, 1, 7][..],
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&[2, 2, 1, 7][..],
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&[2, 2, 1, 7][..],
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&[2, 2, 1, 7][..],
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&[2, 2, 1, 7][..],
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// (a b c) (d e f)
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&[2, 3, 2][..],
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&[2, 3, 2][..],
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// (g h) (i j k l m)
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&[2, 3, 2][..],
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&[2, 3, 2][..],
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// (n)
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&[2, 3, 1][..],
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// (o) (p q) (r s)
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&[2, 2, 3][..],
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&[2, 2, 3][..],
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&[2, 2, 3][..],
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// (t u v w x y z)
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&[2, 2, 1][..],
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// [ (a b c) (d e f) ]
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// [ (g h) (i j k l m) ]
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// [ (n) ]
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&[2, 3][..],
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&[2, 3][..],
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&[2, 3,][..],
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// [ (o) (p q) (r s) ]
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// [ (t u v w x y z) ]
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&[2, 2][..],
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&[2, 2][..],
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// {
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// [ (a b c) (d e f) ]
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// [ (g h) (i j k l m) ]
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// [ (n) ]
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// }
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// {
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// [ (o) (p q) (r s) ]
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// [ (t u v w x y z) ]
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// }
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&[2][..],
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&[2][..]
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][..]
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);
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// It is possible to say, to some degree, that count is an "amalgamation" of len (see
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// each len line result and compare them with the count results)
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}
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