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