lang: Fix new `trim*` function mappings

Fixes #23413

CHANGELOG.md

@@ -1,10 +1,11 @@
 ## 0.12.17 (Unreleased)
-## 0.12.16 (November 18, 2019)
 
 NEW FEATURES:
 
 *  lang/funcs: Add `trim*` functions
 
+## 0.12.16 (November 18, 2019)
+
 BUG FIXES:
 
 * command/0.12upgrade: fix panic when int value is out of range ([#23394](https://github.com/hashicorp/terraform/issues/23394))

lang/functions.go

@@ -118,7 +118,10 @@ func (s *Scope) Functions() map[string]function.Function {
 			"tolist":           funcs.MakeToFunc(cty.List(cty.DynamicPseudoType)),
 			"tomap":            funcs.MakeToFunc(cty.Map(cty.DynamicPseudoType)),
 			"transpose":        funcs.TransposeFunc,
+			"trim":             funcs.TrimFunc,
+			"trimprefix":       funcs.TrimPrefixFunc,
 			"trimspace":        funcs.TrimSpaceFunc,
+			"trimsuffix":       funcs.TrimSuffixFunc,
 			"upper":            stdlib.UpperFunc,
 			"urlencode":        funcs.URLEncodeFunc,
 			"uuid":             funcs.UUIDFunc,

lang/functions_test.go

@@ -837,6 +837,20 @@ func TestFunctions(t *testing.T) {
 			},
 		},
 
+		"trim": {
+			{
+				`trim("?!hello?!", "!?")`,
+				cty.StringVal("hello"),
+			},
+		},
+
+		"trimprefix": {
+			{
+				`trimprefix("helloworld", "hello")`,
+				cty.StringVal("world"),
+			},
+		},
+
 		"trimspace": {
 			{
 				`trimspace(" hello ")`,
@@ -844,6 +858,13 @@ func TestFunctions(t *testing.T) {
 			},
 		},
 
+		"trimsuffix": {
+			{
+				`trimsuffix("helloworld", "world")`,
+				cty.StringVal("hello"),
+			},
+		},
+
 		"upper": {
 			{
 				`upper("hello")`,