celfilemodified.diff

diff --git a/pkg/matcher/cel.go b/pkg/matcher/cel.go
index 822d8812..c0a9a416 100644
--- a/pkg/matcher/cel.go
+++ b/pkg/matcher/cel.go
@@ -5,8 +5,11 @@ import (
 
 	"github.com/google/cel-go/cel"
 	"github.com/google/cel-go/checker/decls"
+	"github.com/google/cel-go/common/types"
 	"github.com/google/cel-go/common/types/ref"
+	"github.com/google/cel-go/interpreter/functions"
 	"github.com/openshift-pipelines/pipelines-as-code/pkg/params/info"
+	exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
 )
 
 func celEvaluate(expr string, event *info.Event) (ref.Val, error) {
@@ -17,6 +20,7 @@ func celEvaluate(expr string, event *info.Event) (ref.Val, error) {
 	}
 
 	env, err := cel.NewEnv(
+		cel.Lib(celPac{}),
 		cel.Declarations(
 			decls.NewVar("event", decls.String),
 			decls.NewVar("target_branch", decls.String),
@@ -46,3 +50,31 @@ func celEvaluate(expr string, event *info.Event) (ref.Val, error) {
 	}
 	return out, nil
 }
+
+type celPac struct{}
+
+func Triggers() cel.EnvOption {
+	return cel.Lib(celPac{})
+}
+
+func (t celPac) ProgramOptions() []cel.ProgramOption {
+	return []cel.ProgramOption{
+		cel.Functions(
+			&functions.Overload{
+				Operator: "fileChanged",
+				Function: fileChanged},
+		)}
+}
+
+func fileChanged(vals ...ref.Val) ref.Val {
+	return types.Bool(true)
+}
+
+func (celPac) CompileOptions() []cel.EnvOption {
+	mapStrDyn := decls.NewMapType(decls.String, decls.Dyn)
+	return []cel.EnvOption{cel.Declarations(
+		decls.NewFunction("fileChanged",
+			decls.NewInstanceOverload("file_changed",
+				[]*exprpb.Type{mapStrDyn, decls.String, decls.String}, decls.Bool)),
+	)}
+}