ruby - bracket-push

ruby/bracket-push/README.md

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+# Bracket Push
+
+Given a string containing brackets `[]`, braces `{}`, parentheses `()`,
+or any combination thereof, verify that any and all pairs are matched
+and nested correctly.
+
+* * * *
+
+For installation and learning resources, refer to the
+[Ruby resources page](http://exercism.io/languages/ruby/resources).
+
+For running the tests provided, you will need the Minitest gem. Open a
+terminal window and run the following command to install minitest:
+
+    gem install minitest
+
+If you would like color output, you can `require 'minitest/pride'` in
+the test file, or note the alternative instruction, below, for running
+the test file.
+
+Run the tests from the exercise directory using the following command:
+
+    ruby bracket_push_test.rb
+
+To include color from the command line:
+
+    ruby -r minitest/pride bracket_push_test.rb
+
+
+## Source
+
+Ginna Baker
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

ruby/bracket-push/bracket_push.rb

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+# Brackets class
+class Brackets
+  PAIRS = { '[' => ']', '{' => '}', '(' => ')' }.freeze
+
+  def self.paired?(text)
+    stack = []
+    text.chars.each do |char|
+      stack.push(char) if PAIRS.key?(char)
+      return false if PAIRS.key(char) && PAIRS.key(char) != stack.pop
+    end
+    stack.empty?
+  end
+end

ruby/bracket-push/bracket_push_test.rb

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+require 'minitest/autorun'
+require_relative 'bracket_push'
+
+# Common test data version: 1.4.0 602c610
+class BracketPushTest < Minitest::Test
+  def test_paired_square_brackets
+    # skip
+    assert Brackets.paired?('[]')
+  end
+
+  def test_empty_string
+    # skip
+    assert Brackets.paired?('')
+  end
+
+  def test_unpaired_brackets
+    # skip
+    refute Brackets.paired?('[[')
+  end
+
+  def test_wrong_ordered_brackets
+    # skip
+    refute Brackets.paired?('}{')
+  end
+
+  def test_wrong_closing_bracket
+    # skip
+    refute Brackets.paired?('{]')
+  end
+
+  def test_paired_with_whitespace
+    # skip
+    assert Brackets.paired?('{ }')
+  end
+
+  def test_partially_paired_brackets
+    # skip
+    refute Brackets.paired?('{[])')
+  end
+
+  def test_simple_nested_brackets
+    # skip
+    assert Brackets.paired?('{[]}')
+  end
+
+  def test_several_paired_brackets
+    # skip
+    assert Brackets.paired?('{}[]')
+  end
+
+  def test_paired_and_nested_brackets
+    # skip
+    assert Brackets.paired?('([{}({}[])])')
+  end
+
+  def test_unopened_closing_brackets
+    # skip
+    refute Brackets.paired?('{[)][]}')
+  end
+
+  def test_unpaired_and_nested_brackets
+    # skip
+    refute Brackets.paired?('([{])')
+  end
+
+  def test_paired_and_wrong_nested_brackets
+    # skip
+    refute Brackets.paired?('[({]})')
+  end
+
+  def test_paired_and_incomplete_brackets
+    # skip
+    refute Brackets.paired?('{}[')
+  end
+
+  def test_math_expression
+    # skip
+    assert Brackets.paired?('(((185 + 223.85) * 15) - 543)/2')
+  end
+
+  def test_complex_latex_expression
+    # skip
+    string = '\left(\begin{array}{cc} \frac{1}{3} & x\\ ' +
+             '\mathrm{e}^{x} &... x^2 \end{array}\right)'
+    assert Brackets.paired?(string)
+  end
+end