utility.rb: Functionality shared across sapling

- Added some constants, specifically those used for brand new trees
- Moved the verify functionality into here

lib/sapling/utility.rb

@@ -0,0 +1,59 @@
+# Utility functionality for all of Sapling to reference
+
+# Constants
+
+# A series of constants for handing a brand new tree. The skeleton tree provides
+# a very basic introduction to Sapling. More details can be found in the
+# documentation.
+
+# The default trunk text of a new tree
+SKELE_TRUNK_TEXT = "Welcome to the Sapling Editor. For details, please see the
+documentation!"
+
+# The default first-branch text of a new tree
+SKELE_BRANCH_TEXT = "The first branch is always shown by default. It should act
+as the introduction to the story. From here, the user enters your world!"
+
+# The default first-leaf text of the first branch of a new tree. The leaf points
+# to it's own branch. The only way out of the program is to either force-quit or
+# reply with option 0.
+SKELE_LEAF_TEXT = "Each branch can have any number of leaves, which represent
+the options a user has on that branch. Each leaf points to another branch, or
+can point to branch 0 to immediately exit."
+
+# The final tree
+SKELETON_TREE = [
+  {"trunk" => "#{SKELE_TRUNK_TEXT}"},
+  {"branch" => {
+    "number" => 1,
+    "text" => "#{SKELE_BRANCH_TEXT}",
+    "leaf" => [{
+      "text" => "#{SKELE_LEAF_TEXT}",
+      "branch" => 1
+      }]
+    }
+  }
+]
+
+
+# Verify that a file is a dialogue tree file.
+#
+# @param file [File] The provided file
+# @return [Boolean] True if the file is a tree; false otherwise
+def verify_tree(file)
+  results = []
+  begin
+    tree = YAML.load_file(file)
+    results << tree[0].keys.include?("trunk")
+    results << tree[1]["branch"].keys.include?("number")
+    results << tree[1]["branch"].keys.include?("text")
+    results << tree[1]["branch"].keys.include?("leaf")
+  rescue
+    puts "Sorry chummer, I don't think this is a tree."
+    puts "Verify your YAML file is formatted properly."
+    results << false
+  end
+
+  results.include?(false) ? false : true
+
+end