Add matching-brackets exercise (#694)

config.json

@@ -408,6 +408,14 @@
         "prerequisites": [],
         "difficulty": 1
       },
+      {
+        "slug": "matching-brackets",
+        "name": "Matching Brackets",
+        "uuid": "9f763780-2d60-4cf7-a548-86604338aa1a",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "matrix",
         "name": "Matrix",

exercises/practice/matching-brackets/.docs/instructions.md

@@ -0,0 +1,5 @@
+# Instructions
+
+Given a string containing brackets `[]`, braces `{}`, parentheses `()`, or any combination thereof, verify that any and all pairs are matched and nested correctly.
+Any other characters should be ignored.
+For example, `"{what is (42)}?"` is balanced and `"[text}"` is not.

exercises/practice/matching-brackets/.docs/introduction.md

@@ -0,0 +1,8 @@
+# Introduction
+
+You're given the opportunity to write software for the Bracketeer™, an ancient but powerful mainframe.
+The software that runs on it is written in a proprietary language.
+Much of its syntax is familiar, but you notice _lots_ of brackets, braces and parentheses.
+Despite the Bracketeer™ being powerful, it lacks flexibility.
+If the source code has any unbalanced brackets, braces or parentheses, the Bracketeer™ crashes and must be rebooted.
+To avoid such a scenario, you start writing code that can verify that brackets, braces, and parentheses are balanced before attempting to run it on the Bracketeer™.

exercises/practice/matching-brackets/.meta/config.json

@@ -0,0 +1,21 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "contributors": [
+    "m-dango"
+  ],
+  "files": {
+    "solution": [
+      "lib/MatchingBrackets.pm"
+    ],
+    "test": [
+      "t/matching-brackets.t"
+    ],
+    "example": [
+      ".meta/solutions/lib/MatchingBrackets.pm"
+    ]
+  },
+  "blurb": "Make sure the brackets and braces all match.",
+  "source": "Ginna Baker"
+}

exercises/practice/matching-brackets/.meta/solutions/lib/MatchingBrackets.pm

@@ -0,0 +1,28 @@
+package MatchingBrackets;
+
+use strict;
+use warnings;
+use experimental qw<signatures postderef postderef_qq>;
+
+use Exporter qw<import>;
+our @EXPORT_OK = qw<has_matching_brackets>;
+
+sub has_matching_brackets ($text) {
+    my @stack = ();
+    my %pairs = ( ')' => '(', ']' => '[', '}' => '{' );
+
+    my $is_open  = sub { grep { $_[0] eq $_ } values %pairs; };
+    my $is_close = sub { exists $pairs{ $_[0] }; };
+
+    foreach my $char ( split '', $text ) {
+        if ( $is_open->($char) ) {
+            push @stack, $char;
+        }
+        elsif ( $is_close->($char) ) {
+            return 0 if @stack == 0 || pop(@stack) ne $pairs{$char};
+        }
+    }
+    return @stack == 0;
+}
+
+1;

exercises/practice/matching-brackets/.meta/solutions/t/matching-brackets.t

@@ -0,0 +1 @@
+../../../t/matching-brackets.t

exercises/practice/matching-brackets/.meta/template-data.yaml

@@ -0,0 +1,37 @@
+subs: has_matching_brackets
+
+properties:
+  isPaired:
+    test: |-
+      use Data::Dmp;
+      sprintf(<<'END', dmp($case->{input}{value}), $case->{expected} ? ('T', 'True') : ('DF', 'Defined but False'), dmp($case->{description}));
+      is(
+          has_matching_brackets(%s),
+          %s, # %s
+          %s,
+      );
+      END
+
+stub: |-
+  sub has_matching_brackets ($text) {
+      return undef;
+  }
+
+example: |-
+  sub has_matching_brackets ($text) {
+      my @stack = ();
+      my %pairs = ( ')' => '(', ']' => '[', '}' => '{' );
+
+      my $is_open  = sub { grep {$_[0] eq $_} values %pairs; };
+      my $is_close = sub { exists $pairs{$_[0]}; };
+      
+      foreach my $char (split '', $text) {
+          if ($is_open->($char)) {
+              push @stack, $char;
+          }
+          elsif ($is_close->($char)) {
+              return 0 if @stack == 0 || pop(@stack) ne $pairs{$char};
+          }
+      }
+      return @stack == 0;
+  }

exercises/practice/matching-brackets/.meta/tests.toml

@@ -0,0 +1,70 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[81ec11da-38dd-442a-bcf9-3de7754609a5]
+description = "paired square brackets"
+
+[287f0167-ac60-4b64-8452-a0aa8f4e5238]
+description = "empty string"
+
+[6c3615a3-df01-4130-a731-8ef5f5d78dac]
+description = "unpaired brackets"
+
+[9d414171-9b98-4cac-a4e5-941039a97a77]
+description = "wrong ordered brackets"
+
+[f0f97c94-a149-4736-bc61-f2c5148ffb85]
+description = "wrong closing bracket"
+
+[754468e0-4696-4582-a30e-534d47d69756]
+description = "paired with whitespace"
+
+[ba84f6ee-8164-434a-9c3e-b02c7f8e8545]
+description = "partially paired brackets"
+
+[3c86c897-5ff3-4a2b-ad9b-47ac3a30651d]
+description = "simple nested brackets"
+
+[2d137f2c-a19e-4993-9830-83967a2d4726]
+description = "several paired brackets"
+
+[2e1f7b56-c137-4c92-9781-958638885a44]
+description = "paired and nested brackets"
+
+[84f6233b-e0f7-4077-8966-8085d295c19b]
+description = "unopened closing brackets"
+
+[9b18c67d-7595-4982-b2c5-4cb949745d49]
+description = "unpaired and nested brackets"
+
+[a0205e34-c2ac-49e6-a88a-899508d7d68e]
+description = "paired and wrong nested brackets"
+
+[1d5c093f-fc84-41fb-8c2a-e052f9581602]
+description = "paired and wrong nested brackets but innermost are correct"
+
+[ef47c21b-bcfd-4998-844c-7ad5daad90a8]
+description = "paired and incomplete brackets"
+
+[a4675a40-a8be-4fc2-bc47-2a282ce6edbe]
+description = "too many closing brackets"
+
+[a345a753-d889-4b7e-99ae-34ac85910d1a]
+description = "early unexpected brackets"
+
+[21f81d61-1608-465a-b850-baa44c5def83]
+description = "early mismatched brackets"
+
+[99255f93-261b-4435-a352-02bdecc9bdf2]
+description = "math expression"
+
+[8e357d79-f302-469a-8515-2561877256a1]
+description = "complex latex expression"

exercises/practice/matching-brackets/lib/MatchingBrackets.pm

@@ -0,0 +1,12 @@
+package MatchingBrackets;
+
+use v5.40;
+
+use Exporter qw<import>;
+our @EXPORT_OK = qw<has_matching_brackets>;
+
+sub has_matching_brackets ($text) {
+    return undef;
+}
+
+1;

exercises/practice/matching-brackets/t/matching-brackets.t

@@ -0,0 +1,129 @@
+#!/usr/bin/env perl
+use Test2::V0;
+
+use FindBin qw<$Bin>;
+use lib "$Bin/../lib", "$Bin/../local/lib/perl5";
+
+use MatchingBrackets qw<has_matching_brackets>;
+
+is( # begin: 81ec11da-38dd-442a-bcf9-3de7754609a5
+    has_matching_brackets("[]"),
+    T, # True
+    "paired square brackets",
+); # end: 81ec11da-38dd-442a-bcf9-3de7754609a5
+
+is( # begin: 287f0167-ac60-4b64-8452-a0aa8f4e5238
+    has_matching_brackets(""),
+    T, # True
+    "empty string",
+); # end: 287f0167-ac60-4b64-8452-a0aa8f4e5238
+
+is( # begin: 6c3615a3-df01-4130-a731-8ef5f5d78dac
+    has_matching_brackets("[["),
+    DF, # Defined but False
+    "unpaired brackets",
+); # end: 6c3615a3-df01-4130-a731-8ef5f5d78dac
+
+is( # begin: 9d414171-9b98-4cac-a4e5-941039a97a77
+    has_matching_brackets("}{"),
+    DF, # Defined but False
+    "wrong ordered brackets",
+); # end: 9d414171-9b98-4cac-a4e5-941039a97a77
+
+is( # begin: f0f97c94-a149-4736-bc61-f2c5148ffb85
+    has_matching_brackets("{]"),
+    DF, # Defined but False
+    "wrong closing bracket",
+); # end: f0f97c94-a149-4736-bc61-f2c5148ffb85
+
+is( # begin: 754468e0-4696-4582-a30e-534d47d69756
+    has_matching_brackets("{ }"),
+    T, # True
+    "paired with whitespace",
+); # end: 754468e0-4696-4582-a30e-534d47d69756
+
+is( # begin: ba84f6ee-8164-434a-9c3e-b02c7f8e8545
+    has_matching_brackets("{[])"),
+    DF, # Defined but False
+    "partially paired brackets",
+); # end: ba84f6ee-8164-434a-9c3e-b02c7f8e8545
+
+is( # begin: 3c86c897-5ff3-4a2b-ad9b-47ac3a30651d
+    has_matching_brackets("{[]}"),
+    T, # True
+    "simple nested brackets",
+); # end: 3c86c897-5ff3-4a2b-ad9b-47ac3a30651d
+
+is( # begin: 2d137f2c-a19e-4993-9830-83967a2d4726
+    has_matching_brackets("{}[]"),
+    T, # True
+    "several paired brackets",
+); # end: 2d137f2c-a19e-4993-9830-83967a2d4726
+
+is( # begin: 2e1f7b56-c137-4c92-9781-958638885a44
+    has_matching_brackets("([{}({}[])])"),
+    T, # True
+    "paired and nested brackets",
+); # end: 2e1f7b56-c137-4c92-9781-958638885a44
+
+is( # begin: 84f6233b-e0f7-4077-8966-8085d295c19b
+    has_matching_brackets("{[)][]}"),
+    DF, # Defined but False
+    "unopened closing brackets",
+); # end: 84f6233b-e0f7-4077-8966-8085d295c19b
+
+is( # begin: 9b18c67d-7595-4982-b2c5-4cb949745d49
+    has_matching_brackets("([{])"),
+    DF, # Defined but False
+    "unpaired and nested brackets",
+); # end: 9b18c67d-7595-4982-b2c5-4cb949745d49
+
+is( # begin: a0205e34-c2ac-49e6-a88a-899508d7d68e
+    has_matching_brackets("[({]})"),
+    DF, # Defined but False
+    "paired and wrong nested brackets",
+); # end: a0205e34-c2ac-49e6-a88a-899508d7d68e
+
+is( # begin: 1d5c093f-fc84-41fb-8c2a-e052f9581602
+    has_matching_brackets("[({}])"),
+    DF, # Defined but False
+    "paired and wrong nested brackets but innermost are correct",
+); # end: 1d5c093f-fc84-41fb-8c2a-e052f9581602
+
+is( # begin: ef47c21b-bcfd-4998-844c-7ad5daad90a8
+    has_matching_brackets("{}["),
+    DF, # Defined but False
+    "paired and incomplete brackets",
+); # end: ef47c21b-bcfd-4998-844c-7ad5daad90a8
+
+is( # begin: a4675a40-a8be-4fc2-bc47-2a282ce6edbe
+    has_matching_brackets("[]]"),
+    DF, # Defined but False
+    "too many closing brackets",
+); # end: a4675a40-a8be-4fc2-bc47-2a282ce6edbe
+
+is( # begin: a345a753-d889-4b7e-99ae-34ac85910d1a
+    has_matching_brackets(")()"),
+    DF, # Defined but False
+    "early unexpected brackets",
+); # end: a345a753-d889-4b7e-99ae-34ac85910d1a
+
+is( # begin: 21f81d61-1608-465a-b850-baa44c5def83
+    has_matching_brackets("{)()"),
+    DF, # Defined but False
+    "early mismatched brackets",
+); # end: 21f81d61-1608-465a-b850-baa44c5def83
+
+is( # begin: 99255f93-261b-4435-a352-02bdecc9bdf2
+    has_matching_brackets("(((185 + 223.85) * 15) - 543)/2"),
+    T, # True
+    "math expression",
+); # end: 99255f93-261b-4435-a352-02bdecc9bdf2
+
+is( # begin: 8e357d79-f302-469a-8515-2561877256a1
+    has_matching_brackets("\\left(\\begin{array}{cc} \\frac{1}{3} & x\\\\ \\mathrm{e}^{x} &... x^2 \\end{array}\\right)"),
+    T, # True
+    "complex latex expression",
+); # end: 8e357d79-f302-469a-8515-2561877256a1
+
+done_testing;