[ruby/prism] Add comments on flags

https://github.com/ruby/prism/commit/3abd09c803

prism/config.yml

@@ -333,12 +333,14 @@ flags:
     values:
       - name: KEYWORD_SPLAT
         comment: "if arguments contain keyword splat"
+    comment: Flags for arguments nodes.
   - name: CallNodeFlags
     values:
       - name: SAFE_NAVIGATION
         comment: "&. operator"
       - name: VARIABLE_CALL
         comment: "a call that could have been a local variable"
+    comment: Flags for call nodes.
   - name: IntegerBaseFlags
     values:
       - name: BINARY
@@ -349,14 +351,17 @@ flags:
         comment: "0d or no prefix"
       - name: HEXADECIMAL
         comment: "0x prefix"
+    comment: Flags for integer nodes that correspond to the base of the integer.
   - name: LoopFlags
     values:
       - name: BEGIN_MODIFIER
         comment: "a loop after a begin statement, so the body is executed first before the condition"
+    comment: Flags for while and until loop nodes.
   - name: RangeFlags
     values:
       - name: EXCLUDE_END
         comment: "... operator"
+    comment: Flags for range and flip-flop nodes.
   - name: RegularExpressionFlags
     values:
       - name: IGNORE_CASE
@@ -375,10 +380,12 @@ flags:
         comment: "s - forces the Windows-31J encoding"
       - name: UTF_8
         comment: "u - forces the UTF-8 encoding"
+    comment: Flags for regular expression and match last line nodes.
   - name: StringFlags
     values:
       - name: FROZEN
         comment: "frozen by virtue of a `frozen_string_literal` comment"
+    comment: Flags for string nodes.
 nodes:
   - name: AliasGlobalVariableNode
     fields:

prism/templates/include/prism/ast.h.erb

@@ -105,7 +105,9 @@ typedef struct pm_<%= node.human %> {
 <%- end -%>
 <%- flags.each do |flag| -%>
 
-// <%= flag.name %>
+/**
+ * <%= flag.comment %>
+ */
 typedef enum pm_<%= flag.human %> {
     <%- flag.values.each_with_index do |value, index| -%>
     PM_<%= flag.human.upcase %>_<%= value.name %> = 1 << <%= index %>,

prism/templates/lib/prism/node.rb.erb

@@ -234,6 +234,7 @@ module Prism
   <%- end -%>
   <%- flags.each_with_index do |flag, flag_index| -%>
 
+  # <%= flag.comment %>
   module <%= flag.name %>
     <%- flag.values.each_with_index do |value, index| -%>
     # <%= value.comment %>

prism/templates/template.rb

@@ -321,12 +321,13 @@ module Prism
       end
     end
 
-    attr_reader :name, :human, :values
+    attr_reader :name, :human, :values, :comment
 
     def initialize(config)
       @name = config.fetch("name")
       @human = @name.gsub(/(?<=.)[A-Z]/, "_\\0").downcase
       @values = config.fetch("values").map { |flag| Flag.new(flag) }
+      @comment = config.fetch("comment")
     end
   end