diff --git a/userspace/digwatch/lua/compiler.lua b/userspace/digwatch/lua/compiler.lua
index f804cba3..043660fd 100644
--- a/userspace/digwatch/lua/compiler.lua
+++ b/userspace/digwatch/lua/compiler.lua
@@ -177,9 +177,11 @@ end
 local G = {
    V"Start", -- Entry rule
 
-   Start = V"Skip" * (V"MacroDef" / macro + V"Rule" / rule)^-1 * -1 + report_error();
+   Start = V"Skip" * (V"Comment" + V"MacroDef" / macro + V"Rule" / rule)^-1 * -1 + report_error();
 
   -- Grammar
+   Comment = P"#" * P(1)^0;
+
    Rule = V"Filter" / filter * ((V"Skip" * V"Pipe" * V"Skip" * (P(1)^0 / outputformat) )^-1 );
 
    Filter = V"OrExpression";
diff --git a/userspace/digwatch/lua/smoke.sh b/userspace/digwatch/lua/smoke.sh
index 216b8097..d4db4885 100755
--- a/userspace/digwatch/lua/smoke.sh
+++ b/userspace/digwatch/lua/smoke.sh
@@ -27,6 +27,8 @@ function bad
 good "  "
 good "  a"
 good "a and b"
+good "#a and b; a and b"
+good "#a and b; # ; ; a and b"
 good "(a)"
 good "(a and b)"
 good "(a.a exists and b)"
diff --git a/userspace/digwatch/lua/test.lua b/userspace/digwatch/lua/test.lua
index 03a716c9..b36a699d 100644
--- a/userspace/digwatch/lua/test.lua
+++ b/userspace/digwatch/lua/test.lua
@@ -21,7 +21,7 @@ for str in string.gmatch(arg[1], "([^;]+)") do
    doit(str)
 end
 
-if not (ast) then
+if (ast and ast.type) then
    compiler.parser.print_ast(ast)
 end