brew-aspell-dictionaries: move to homebrew/core.

Experiment with moving this from Homebrew/brew to Homebrew/homebrew-core
(to allow future additions of formula-specific `cmd`s).

cmd/brew-aspell-dictionaries.rb

@@ -0,0 +1,40 @@
+#:  * `aspell_dictionaries`:
+#:    Generates the new dictionaries for the `aspell` formula.
+
+require "open-uri"
+require "resource"
+require "formula"
+
+dict_url    = "https://ftpmirror.gnu.org/aspell/dict"
+dict_mirror = "https://ftp.gnu.org/gnu/aspell/dict"
+languages   = {}
+
+open("#{dict_url}/0index.html") do |content|
+  content.each_line do |line|
+    break if %r{^</table} =~ line
+    next unless /^<tr><td><a/ =~ line
+
+    fields = line.split('"')
+    lang = fields[1]
+    path = fields[3]
+    lang.tr!("-", "_")
+    languages[lang] = path
+  end
+end
+
+languages.each do |lang, path|
+  r = Resource.new(lang)
+  r.owner = Formulary.factory("aspell")
+  r.url "#{dict_url}/#{path}"
+  r.mirror "#{dict_mirror}/#{path}"
+  r.fetch
+  puts <<-EOS
+    option "with-lang-#{r.name}", "Install #{r.name} dictionary"
+    resource "#{r.name}" do
+      url "#{r.url}"
+      mirror "#{r.mirrors.first}"
+      sha256 "#{r.cached_download.sha256}"
+    end
+
+  EOS
+end