source-info.txt: add some docs about documenting commodities

diff --git a/yarrg/source-info.txt b/yarrg/source-info.txt
index 331a7ed35081357698ffc6cad4e2f5b34c428dd5..aa5593daf55354c3b31ffe90736516aebe334e7f 100644 (file)
--- a/yarrg/source-info.txt
+++ b/yarrg/source-info.txt
@@ -45,6 +45,19 @@ commodclasses
  *enamel
  *forageables
 
+# Commodities are defined in `commods` sections
+# Each line is
+#  <name> <facts>
+# and the <facts> can be
+#  <mass>kg
+#  <volume>l
+#  *<class> (see commodclasses, above)
+#  @<sort-number>    sort order value, for where in the commods list it goes
+#  @<sort-number>+   sort order value; 10x line number is added
+# The <name> can contain `%<reference>` which is then defined in
+# a `%<reference>` section.
+# Volume defaults to 1l.
+
 commods
  kraken's blood                1kg             *dye                    @105
  %d dye                        1kg             *dye                    @0