Add vimscript (#85)

* Add vimscript

* leading blank lines are trimmed

Author: glennj

lib/languages/vimscript.txt

@@ -0,0 +1,2 @@
+!e stop_at_first_loc
+"\p

test/languages/vimscript_test.rb

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+require "test_helper"
+
+class SnippetExtractor::Languages::VimscriptTest < Minitest::Test
+  def test_full_example
+    code = <<~'CODE'
+      "
+      " Create an implementation of the atbash cipher, an ancient encryption system
+      " created in the Middle East.
+      "
+      " Examples:
+      "
+      "   :echo AtbashEncode('test')
+      "   gvhg
+      "
+      "   :echo AtbashDecode('gvhg')
+      "   test
+      "
+      "   :echo AtbashDecode('gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt')
+      "   thequickbrownfoxjumpsoverthelazydog
+      "
+
+      function! AtbashDecode(cipher) abort
+          let str = tolower(substitute(a:cipher, '[^[:alnum:]]', '', 'g'))
+          let str = tr(str, 'abcdefghijklmnopqrstuvwxyz', 'zyxwvutsrqponmlkjihgfedcba')
+          return str
+      endfunction
+
+      function! AtbashEncode(plaintext) abort
+          let str = AtbashDecode(a:plaintext)
+          " let str = substitute(str, '.\{5\}', '& ', 'g')
+          " return substitute(str, ' $', '', '')
+          return join(split(str, '.\{5\}\zs'), ' ')
+      endfunction
+    CODE
+
+    expected = <<~'CODE'
+      function! AtbashDecode(cipher) abort
+          let str = tolower(substitute(a:cipher, '[^[:alnum:]]', '', 'g'))
+          let str = tr(str, 'abcdefghijklmnopqrstuvwxyz', 'zyxwvutsrqponmlkjihgfedcba')
+          return str
+      endfunction
+
+      function! AtbashEncode(plaintext) abort
+          let str = AtbashDecode(a:plaintext)
+          " let str = substitute(str, '.\{5\}', '& ', 'g')
+          " return substitute(str, ' $', '', '')
+    CODE
+    assert_equal expected, SnippetExtractor::ExtractSnippet.(code, :vimscript)
+  end
+end