+# Look for @example environments preceded with lines such as:
+#
+# @comment file calc.y
+# or
+# @comment file calc.y: 3
+#
+# and output their content in that file (calc.y). When numbers are
+# provided, use them to decide the output order (block numbered 1 is
+# output before block 2, even if the latter appears before). The same
+# number may be used several time, in which case the order of
+# appearance is used.
+