gracefully handle missing toml gem in config.rb

1 files changed, 13 insertions, 3 deletions

diff --git a/lib/config.rb b/lib/config.rb
index b0123e0..2a13ae0 100644
--- a/lib/config.rb
+++ b/lib/config.rb
@@ -1,9 +1,19 @@
-require 'toml'
+begin
+  require 'toml'
+  TOML_AVAILABLE = true
+rescue LoadError
+  TOML_AVAILABLE = false
+end
 
 module RCM
-  # Configuration
+  # Configuration — config.toml is optional. If the toml gem is not installed
+  # or no config.toml exists, config() will raise a helpful error when called.
   module Config
-    @@config = File.exist?('config.toml') ? TOML.load_file('config.toml') : {}
+    @@config = if TOML_AVAILABLE && File.exist?('config.toml')
+                 TOML.load_file('config.toml')
+               else
+                 {}
+               end
 
     def config(key)
       raise "No such config key: #{key}" unless @@config.key?(key)