Add inline documentation to describe each class

lib/sub_diff/adapter.rb

@@ -1,4 +1,10 @@
 module SubDiff
+  # Constructs an instance of {Sub} or {Gsub} to be
+  # used as a receiver for delegated calls to `diff`.
+  #
+  # Used internally by {Builder}.
+  #
+  # @api private
   class Adapter
     extend Forwardable
 

lib/sub_diff/builder.rb

@@ -1,4 +1,10 @@
 module SubDiff
+  # Performs a {Sub} or {Gsub} replacement and returns
+  # the resulting {Collection} of {Diff} objects.
+  #
+  # Used internally by {String#sub_diff} and {String#gsub_diff}.
+  #
+  # @api private
   class Builder
     attr_reader :string, :diff_method
 

lib/sub_diff/collection.rb

@@ -1,4 +1,11 @@
 module SubDiff
+  # Stores a collection of {Diff} objects for all matches
+  # from {String#sub_diff} or {String#gsub_diff} replacement.
+  #
+  # It behaves like a {String} with added {Enumerable} behavior
+  # that delegates to an internal {Array} of {Diff} objects.
+  #
+  # @api public
   class Collection < SimpleDelegator
     extend Forwardable
     include Enumerable

lib/sub_diff/diff.rb

@@ -1,4 +1,13 @@
 module SubDiff
+  # Stores a single match (and optional replacement)
+  # from {String#sub} or {String#gsub} replacements.
+  #
+  # It behaves just like a {String} but has some additional
+  # methods that provides references to the old string,
+  # the newly replaced string, and a boolean to check
+  # if a replacement was actually made.
+  #
+  # @api public
   class Diff < SimpleDelegator
     attr_reader :value_was
 

lib/sub_diff/differ.rb

@@ -1,4 +1,10 @@
 module SubDiff
+  # Performs a {String#sub} or {String#gsub} replacement
+  # while yielding each match to a block.
+  #
+  # Used internally by {Sub}.
+  #
+  # @api private
   class Differ
     extend Forwardable
 

lib/sub_diff/gsub.rb

@@ -1,4 +1,10 @@
 module SubDiff
+  # Processes matches for {String#gsub} replacements
+  # to build up a {Collection} of {Diff} objects.
+  #
+  # Used internally by {Adapter}.
+  #
+  # @api private
   class Gsub < Sub
     private
 

lib/sub_diff/sub.rb

@@ -1,4 +1,10 @@
 module SubDiff
+  # Processes matches for {String#sub} replacements
+  # to build up a {Collection} of {Diff} objects.
+  #
+  # Used internally by {Adapter}.
+  #
+  # @api private
   class Sub
     attr_reader :differ