fallback to other filenames if 'log' is a directory

lib/letters/core_ext.rb

@@ -74,7 +74,10 @@ def e(opts={})
     def f(opts={})
       opts = { format: "yaml", name: "log" }.merge opts
       tap do |o|
-        File.open(opts[:name], "w+") do |file|
+        suffixes = [""] + (1..50).to_a
+        deduper = suffixes.detect {|x| !File.directory? "#{opts[:name]}#{x}" }
+
+        File.open("#{opts[:name]}#{deduper}", "w+") do |file|
           # Override :stream
           opts.merge! :stream => file
           Helpers.message opts

spec/letters/core_ext_spec.rb

@@ -120,6 +120,17 @@ module Letters
           File.read("log").chomp.should == hash.awesome_inspect
         end
       end
+
+      describe "when 'log' is a directory" do
+        before { FileUtils.mkdir "log" }
+        after { FileUtils.rm_rf "log" }
+
+        it "appends the first integer that de-dupes the name" do
+          File.exist?("log1").should be_false
+          lambda { hash.f }.should_not raise_error
+          File.exist?("log1").should be_true
+        end
+      end
     end
 
     describe "#j (jump)" do