Build a composite license that traverses and expression tree

2 files changed, 61 insertions, 7 deletions

diff --git a/lib/spandx/core/guess.rb b/lib/spandx/core/guess.rb
index 4383374..62967ce 100644
--- a/lib/spandx/core/guess.rb
+++ b/lib/spandx/core/guess.rb
@@ -7,7 +7,6 @@ module Spandx
 
       def initialize(catalogue)
         @catalogue = catalogue
-        @expression_cache = {}
       end
 
       def license_for(raw)
@@ -79,12 +78,8 @@ module Spandx
       end
 
       def from_expression(content)
-        @expression_cache.fetch(content.raw) do
-          tree = Spdx::Expression.new.parse(content.raw)
-          @expression_cache[content.raw] = catalogue[tree[0][:left].to_s]
-        end
-      rescue Parslet::ParseFailed
-        nil
+        Spandx::Spdx::CompositeLicense
+          .from_expression(content.raw, catalogue)
       end
     end
   end
diff --git a/lib/spandx/spdx/composite_license.rb b/lib/spandx/spdx/composite_license.rb
new file mode 100644
index 0000000..e429778
--- /dev/null
+++ b/lib/spandx/spdx/composite_license.rb
@@ -0,0 +1,59 @@
+
+module Spandx
+  module Spdx
+    class CompositeLicense < License
+      def self.from_expression(expression, catalogue)
+        tree = Spdx::Expression.new.parse(expression)
+        new(tree[0], catalogue)
+      rescue Parslet::ParseFailed
+        nil
+      end
+
+      def initialize(tree, catalogue)
+        @catalogue = catalogue
+        @tree = tree
+        super({ })
+      end
+
+      def id
+        if right
+          ["(#{left.id}", operator, "#{right.id})"].compact.join(' ').squeeze(' ').strip
+        else
+          "#{left.id}"
+        end
+      end
+
+      def name
+        if right
+          [left.name, operator, right.name].compact.join(' ').squeeze(' ').strip
+        else
+          left.name
+        end
+      end
+
+      private
+
+      def left
+        node_for(@tree[:left])
+      end
+
+      def operator
+        @tree[:op].to_s.upcase
+      end
+
+      def right
+        node_for(@tree[:right])
+      end
+
+      def node_for(item)
+        return if item.nil?
+
+        if item.is_a?(Hash)
+          self.class.new(item, @catalogue)
+        else
+          @catalogue[item.to_s] || License.unknown(item.to_s)
+        end
+      end
+    end
+  end
+end