From 723c361171a0cb600c2f481da68326aa60949968 Mon Sep 17 00:00:00 2001
From: Denis Arh <denis.arh@gmail.com>
Date: Tue, 30 Mar 2021 13:19:46 +0200
Subject: [PATCH] Use built-in len function for wf exec

---
 pkg/expr/func_gen.go      | 14 ++++++++++++++
 pkg/expr/func_gen_test.go | 21 +++++++++++++++++++++
 pkg/expr/func_str.go      |  5 -----
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/pkg/expr/func_gen.go b/pkg/expr/func_gen.go
index b4f9dcbd8..c211a15c6 100644
--- a/pkg/expr/func_gen.go
+++ b/pkg/expr/func_gen.go
@@ -12,6 +12,7 @@ func GenericFunctions() []gval.Language {
 		gval.Function("coalesce", coalesce),
 		gval.Function("isEmpty", isEmpty),
 		gval.Function("isNil", isNil),
+		gval.Function("length", length),
 	}
 }
 
@@ -25,6 +26,19 @@ func coalesce(aa ...interface{}) interface{} {
 	return nil
 }
 
+func length(i interface{}) int {
+	if isEmpty(i) {
+		return 0
+	}
+
+	switch reflect.TypeOf(i).Kind() {
+	case reflect.Slice, reflect.Array, reflect.Ptr, reflect.Map, reflect.String:
+		return reflect.ValueOf(i).Len()
+	}
+
+	return 0
+}
+
 func isNil(i interface{}) bool {
 	if i == nil {
 		return true
diff --git a/pkg/expr/func_gen_test.go b/pkg/expr/func_gen_test.go
index 4a84145cc..3298a0a07 100644
--- a/pkg/expr/func_gen_test.go
+++ b/pkg/expr/func_gen_test.go
@@ -87,3 +87,24 @@ func Test_empty(t *testing.T) {
 		req.Equal(tst.expect, isEmpty(tst.value))
 	}
 }
+
+func Test_length(t *testing.T) {
+	var (
+		req = require.New(t)
+
+		tcc = []struct {
+			len   int
+			value interface{}
+		}{
+			{0, []string{}},
+			{0, map[string]string{}},
+			{3, "foo"},
+			{0, make(chan string)},
+			{0, 34234},
+		}
+	)
+
+	for _, tst := range tcc {
+		req.Equal(tst.len, length(tst.value))
+	}
+}
diff --git a/pkg/expr/func_str.go b/pkg/expr/func_str.go
index c51dee54d..7cc1cbeb2 100644
--- a/pkg/expr/func_str.go
+++ b/pkg/expr/func_str.go
@@ -15,7 +15,6 @@ func StringFunctions() []gval.Language {
 		gval.Function("trim", strings.TrimSpace),
 		gval.Function("trimLeft", strings.TrimLeft),
 		gval.Function("trimRight", strings.TrimRight),
-		gval.Function("length", length),
 		gval.Function("toLower", strings.ToLower),
 		gval.Function("toUpper", strings.ToUpper),
 		gval.Function("shortest", shortest),
@@ -59,10 +58,6 @@ func longest(f string, aa ...string) string {
 	return f
 }
 
-func length(s string) int {
-	return len(s)
-}
-
 // title works similarly as strings.ToTitle, with the expception
 // of uppercasing only the first word in line
 func title(s string) string {