src/test/run-pass/match-vec-alternatives.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11
  12 #![feature(advanced_slice_patterns)]
  13 #![feature(slice_patterns)]
  14
  15 fn match_vecs<'a, T>(l1: &'a [T], l2: &'a [T]) -> &'static str {
  16     match (l1, l2) {
  17         (&[], &[]) => "both empty",
  18         (&[], &[..]) | (&[..], &[]) => "one empty",
  19         (&[..], &[..]) => "both non-empty"
  20     }
  21 }
  22
  23 fn match_vecs_cons<'a, T>(l1: &'a [T], l2: &'a [T]) -> &'static str {
  24     match (l1, l2) {
  25         (&[], &[]) => "both empty",
  26         (&[], &[_, ..]) | (&[_, ..], &[]) => "one empty",
  27         (&[_, ..], &[_, ..]) => "both non-empty"
  28     }
  29 }
  30
  31 fn match_vecs_snoc<'a, T>(l1: &'a [T], l2: &'a [T]) -> &'static str {
  32     match (l1, l2) {
  33         (&[], &[]) => "both empty",
  34         (&[], &[.., _]) | (&[.., _], &[]) => "one empty",
  35         (&[.., _], &[.., _]) => "both non-empty"
  36     }
  37 }
  38
  39 fn match_nested_vecs_cons<'a, T>(l1: Option<&'a [T]>, l2: Result<&'a [T], ()>) -> &'static str {
  40     match (l1, l2) {
  41         (Some(&[]), Ok(&[])) => "Some(empty), Ok(empty)",
  42         (Some(&[_, ..]), Ok(_)) | (Some(&[_, ..]), Err(())) => "Some(non-empty), any",
  43         (None, Ok(&[])) | (None, Err(())) | (None, Ok(&[_])) => "None, Ok(less than one element)",
  44         (None, Ok(&[_, _, ..])) => "None, Ok(at least two elements)",
  45         _ => "other"
  46     }
  47 }
  48
  49 fn match_nested_vecs_snoc<'a, T>(l1: Option<&'a [T]>, l2: Result<&'a [T], ()>) -> &'static str {
  50     match (l1, l2) {
  51         (Some(&[]), Ok(&[])) => "Some(empty), Ok(empty)",
  52         (Some(&[.., _]), Ok(_)) | (Some(&[.., _]), Err(())) => "Some(non-empty), any",
  53         (None, Ok(&[])) | (None, Err(())) | (None, Ok(&[_])) => "None, Ok(less than one element)",
  54         (None, Ok(&[.., _, _])) => "None, Ok(at least two elements)",
  55         _ => "other"
  56     }
  57 }
  58
  59 fn main() {
  60     assert_eq!(match_vecs(&[1, 2], &[2, 3]), "both non-empty");
  61     assert_eq!(match_vecs(&[], &[1, 2, 3, 4]), "one empty");
  62     assert_eq!(match_vecs::<usize>(&[], &[]), "both empty");
  63     assert_eq!(match_vecs(&[1, 2, 3], &[]), "one empty");
  64
  65     assert_eq!(match_vecs_cons(&[1, 2], &[2, 3]), "both non-empty");
  66     assert_eq!(match_vecs_cons(&[], &[1, 2, 3, 4]), "one empty");
  67     assert_eq!(match_vecs_cons::<usize>(&[], &[]), "both empty");
  68     assert_eq!(match_vecs_cons(&[1, 2, 3], &[]), "one empty");
  69
  70     assert_eq!(match_vecs_snoc(&[1, 2], &[2, 3]), "both non-empty");
  71     assert_eq!(match_vecs_snoc(&[], &[1, 2, 3, 4]), "one empty");
  72     assert_eq!(match_vecs_snoc::<usize>(&[], &[]), "both empty");
  73     assert_eq!(match_vecs_snoc(&[1, 2, 3], &[]), "one empty");
  74
  75     assert_eq!(match_nested_vecs_cons(None, Ok::<&[_], ()>(&[4_usize, 2_usize])),
  76                "None, Ok(at least two elements)");
  77     assert_eq!(match_nested_vecs_cons::<usize>(None, Err(())), "None, Ok(less than one element)");
  78     assert_eq!(match_nested_vecs_cons::<bool>(Some::<&[_]>(&[]), Ok::<&[_], ()>(&[])),
  79                "Some(empty), Ok(empty)");
  80     assert_eq!(match_nested_vecs_cons(Some::<&[_]>(&[1]), Err(())), "Some(non-empty), any");
  81     assert_eq!(match_nested_vecs_cons(Some::<&[_]>(&[(42, ())]), Ok::<&[_], ()>(&[(1, ())])),
  82                "Some(non-empty), any");
  83
  84     assert_eq!(match_nested_vecs_snoc(None, Ok::<&[_], ()>(&[4_usize, 2_usize])),
  85                "None, Ok(at least two elements)");
  86     assert_eq!(match_nested_vecs_snoc::<usize>(None, Err(())), "None, Ok(less than one element)");
  87     assert_eq!(match_nested_vecs_snoc::<bool>(Some::<&[_]>(&[]), Ok::<&[_], ()>(&[])),
  88                "Some(empty), Ok(empty)");
  89     assert_eq!(match_nested_vecs_snoc(Some::<&[_]>(&[1]), Err(())), "Some(non-empty), any");
  90     assert_eq!(match_nested_vecs_snoc(Some::<&[_]>(&[(42, ())]), Ok::<&[_], ()>(&[(1, ())])),
  91                "Some(non-empty), any");
  92 }