Implement patsubt function
diff --git a/eval.go b/eval.go
index 75009a8..e3b90ae 100644
--- a/eval.go
+++ b/eval.go
@@ -32,6 +32,7 @@
 		vars:    vars,
 		funcs: map[string]Func{
 			"subst":    funcSubst,
+			"patsubst": funcPatsubst,
 			"wildcard": funcWildcard,
 			"shell":    funcShell,
 			"warning":  funcWarning,