matching-brackets (#57)

Author: glennj

config.json

@@ -438,6 +438,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 4
+      },
+      {
+        "slug": "matching-brackets",
+        "name": "Matching Brackets",
+        "uuid": "34ca14e4-31a6-4da6-a5ce-44da523bfb12",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
       }
     ]
   },

exercises/practice/matching-brackets/.busted

@@ -0,0 +1,5 @@
+return {
+  default = {
+    ROOT = { '.' }
+  }
+}

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 +1,18 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "matching_brackets.moon"
+    ],
+    "test": [
+      "matching_brackets_spec.moon"
+    ],
+    "example": [
+      ".meta/example.moon"
+    ]
+  },
+  "blurb": "Make sure the brackets and braces all match.",
+  "source": "Ginna Baker"
+}

exercises/practice/matching-brackets/.meta/example.moon

@@ -0,0 +1,18 @@
+push     = table.insert
+pop      = table.remove
+is_empty = (s) -> #s == 0
+
+opener   = { [']']: '[', ['}']: '{', [')']: '(' }
+
+
+{
+  is_paired: (input) ->
+    stack = {}
+
+    for char in input\gmatch '.'
+      switch char
+        when '[', '{', '(' then push stack, char
+        when ']', '}', ')' then return false if opener[char] != pop stack
+
+    is_empty stack
+}

exercises/practice/matching-brackets/.meta/spec_generator.moon

@@ -0,0 +1,5 @@
+{
+  module_imports: {'is_paired'},
+  generate_test: (case, level) ->
+    indent "assert.is_#{case.expected} is_paired #{quote case.input.value\gsub('\\', '\\\\')}", level
+}

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/matching_brackets.moon

@@ -0,0 +1,4 @@
+{
+  is_paired: (input) ->
+    error 'Implement me'
+}

exercises/practice/matching-brackets/matching_brackets_spec.moon

@@ -0,0 +1,62 @@
+import is_paired from require 'matching_brackets'
+
+describe 'matching-brackets', ->
+  it 'paired square brackets', ->
+    assert.is_true is_paired '[]'
+
+  pending 'empty string', ->
+    assert.is_true is_paired ''
+
+  pending 'unpaired brackets', ->
+    assert.is_false is_paired '[['
+
+  pending 'wrong ordered brackets', ->
+    assert.is_false is_paired '}{'
+
+  pending 'wrong closing bracket', ->
+    assert.is_false is_paired '{]'
+
+  pending 'paired with whitespace', ->
+    assert.is_true is_paired '{ }'
+
+  pending 'partially paired brackets', ->
+    assert.is_false is_paired '{[])'
+
+  pending 'simple nested brackets', ->
+    assert.is_true is_paired '{[]}'
+
+  pending 'several paired brackets', ->
+    assert.is_true is_paired '{}[]'
+
+  pending 'paired and nested brackets', ->
+    assert.is_true is_paired '([{}({}[])])'
+
+  pending 'unopened closing brackets', ->
+    assert.is_false is_paired '{[)][]}'
+
+  pending 'unpaired and nested brackets', ->
+    assert.is_false is_paired '([{])'
+
+  pending 'paired and wrong nested brackets', ->
+    assert.is_false is_paired '[({]})'
+
+  pending 'paired and wrong nested brackets but innermost are correct', ->
+    assert.is_false is_paired '[({}])'
+
+  pending 'paired and incomplete brackets', ->
+    assert.is_false is_paired '{}['
+
+  pending 'too many closing brackets', ->
+    assert.is_false is_paired '[]]'
+
+  pending 'early unexpected brackets', ->
+    assert.is_false is_paired ')()'
+
+  pending 'early mismatched brackets', ->
+    assert.is_false is_paired '{)()'
+
+  pending 'math expression', ->
+    assert.is_true is_paired '(((185 + 223.85) * 15) - 543)/2'
+
+  pending 'complex latex expression', ->
+    assert.is_true is_paired '\\left(\\begin{array}{cc} \\frac{1}{3} & x\\\\ \\mathrm{e}^{x} &... x^2 \\end{array}\\right)'