Regex commits for equations parser (#60)

# Description ✍️

Creates regex(input, pattern) function

# Overview 🔍

```c
regex("2 dogs are walking in the streets", "(\\d+ \\w+)") # => "2 dogs"
```

# Checks ☑️

- Regex commits for equations parser
- Add regex tests

ext/libnativemath/extconf.rb

@@ -38,7 +38,7 @@
 end
 
 GIT_REPOSITORY = 'https://github.com/oxeanbits/equations-parser.git'.freeze
-COMMIT = '8c4fab5b8949704cf4d80d4a4a898f451cbb3890'.freeze
+COMMIT = '8769175390cafd9c40b52477f1c97184266c4a68'.freeze
 
 Dir.chdir(BASEDIR) do
   system('git init')

parsec.gemspec

@@ -1,11 +1,11 @@
 Gem::Specification.new do |s|
   s.name                  = 'parsecs'
-  s.version               = '0.11.9'
+  s.version               = '0.12.0'
   s.platform              = Gem::Platform::RUBY
   s.authors               = ['Nilton Vasques', 'Victor Cordeiro', 'Beatriz Fagundes']
   s.email                 = ['[email protected]', '[email protected]', '[email protected]']
-  s.description           = 'ParseCs is a gem to evaluate equations using a lighter and extented version of the muparserx C++ library'
-  s.homepage              = 'https://github.com/niltonvasques/parsec'
+  s.description           = 'Parsecs is a gem to evaluate equations using a lighter and extented version of the muparserx C++ library'
+  s.homepage              = 'https://github.com/oxeanbits/parsec'
   s.summary               = 'A gem to evaluate equations using muparserx C++ library'
   s.files                 = ['lib/parsec.rb', 'lib/string_to_boolean_refinements.rb', 'ext/libnativemath/libnativemath.i',
                              'ext/libnativemath/libnativemath.cpp', 'ext/libnativemath/libnativemath.h']

test/test_parsec.rb

@@ -302,4 +302,40 @@ def test_timediff
     assert_raises(SyntaxError) { parsec.eval_equation('timediff("02:00:00", "02:30:62")') }
     assert_raises(SyntaxError) { parsec.eval_equation('timediff("24:00:00", "02:30:59")') }
   end
+
+  def test_regex
+    parsec = Parsec::Parsec
+    assert_equal('World', parsec.eval_equation('regex("Hello World", "Hello (.*)")'))
+    assert_equal('71', parsec.eval_equation('regex("71 123456789", "([0-9]{2}) [0-9]{9}")'))
+    assert_equal('ISSUE-123', parsec.eval_equation('regex("ISSUE-123 Fix bug", "(ISSUE-[0-9]+) (.*)")'))
+    assert_equal('2019-01-01', parsec.eval_equation('regex("2019-01-01T:08:30", "([0-9]{4}-[0-9]{2}-[0-9]{2})T:[0-9]{2}:[0-9]{2}")'))
+    assert_equal('2019-01', parsec.eval_equation('regex("2019-01-01T:08:30", "([0-9]{4}-[0-9]{2})-[0-9]{2}T:[0-9]{2}:[0-9]{2}")'))
+    assert_equal('2019', parsec.eval_equation('regex("2019-01-01T:08:30", "([0-9]{4})-[0-9]{2}-[0-9]{2}T:[0-9]{2}:[0-9]{2}")'))
+    # Regex tests with no capture group
+    assert_equal('', parsec.eval_equation('regex("Hello World", "Hello .*")'))
+
+    # Regex tests with optional groups
+    assert_equal('1234', parsec.eval_equation('regex("Product 1234 (color: red)", "Product ([0-9]+)( \\\\(color: (.*)\\\\))?")'))
+    assert_equal('1234', parsec.eval_equation('regex("Product 1234", "Product ([0-9]+)( \\\\(color: (.*)\\\\))?")'))
+
+    # Regex tests with alternation
+    assert_equal('Green', parsec.eval_equation('regex("Green Apple", "(Green|Red) Apple")'))
+    assert_equal('Red', parsec.eval_equation('regex("Red Apple", "(Green|Red) Apple")'))
+
+    # Regex tests with character classes
+    assert_equal('A123', parsec.eval_equation('regex("BoxA123", "Box([A-Za-z][0-9]+)")'))
+    assert_equal('C456', parsec.eval_equation('regex("BoxC456", "Box([A-Za-z][0-9]+)")'))
+
+    # Regex tests with positive lookaheads
+    assert_equal('apple', parsec.eval_equation('regex("apple123banana", "([a-z]+)(?=\\\\d+)")'))
+
+    assert_equal('456', parsec.eval_equation('regex("123red456blue", "(\\\\d+)(?=blue)")'))
+
+    # Regex tests with negative lookaheads
+    assert_equal('123', parsec.eval_equation('regex("123red456blue", "(\\\\d+)(?!blue)")'))
+
+    # Regex tests with nested lookaheads
+    assert_equal('apple', parsec.eval_equation('regex("apple123redbanana", "(?=apple)([a-z]+)(?=\\\\d+red)")'))
+    assert_equal('apple', parsec.eval_equation('regex("apple123red456banana", "(?=apple)([a-z]+)(?=(\\\\d+red)\\\\d+banana)")'))
+  end
 end