wip - Parsing envsubst parameters

pkg/yqlib/expression_processing_test.go

@@ -15,6 +15,26 @@ var pathTests = []struct {
 	expectedTokens  []interface{}
 	expectedPostFix []interface{}
 }{
+	{
+		`envsubst(ne)`,
+		append(make([]interface{}, 0), "ENVSUBST"),
+		append(make([]interface{}, 0), "ENVSUBST"),
+	},
+	{
+		`envsubst(nu)`,
+		append(make([]interface{}, 0), "ENVSUBST"),
+		append(make([]interface{}, 0), "ENVSUBST"),
+	},
+	{
+		`envsubst(nu, ne)`,
+		append(make([]interface{}, 0), "ENVSUBST"),
+		append(make([]interface{}, 0), "ENVSUBST"),
+	},
+	{
+		`envsubst(ne, nu)`,
+		append(make([]interface{}, 0), "ENVSUBST"),
+		append(make([]interface{}, 0), "ENVSUBST"),
+	},
 	{
 		`[.a, .b]`,
 		append(make([]interface{}, 0), "[", "a", "UNION", "b", "]"),

pkg/yqlib/expression_tokeniser.go

@@ -507,6 +507,7 @@ func initLexer() (*lex.Lexer, error) {
 	lexer.Add([]byte(`strenv\([^\)]+\)`), envOp(true))
 	lexer.Add([]byte(`env\([^\)]+\)`), envOp(false))
 
+	lexer.Add([]byte(`envsubst\((ne|nu| |,)+\)`), opToken(envsubstOpType))
 	lexer.Add([]byte(`envsubst`), opToken(envsubstOpType))
 
 	lexer.Add([]byte(`\[`), literalToken(openCollect, false))

pkg/yqlib/operator_env.go

@@ -12,6 +12,8 @@ import (
 
 type envOpPreferences struct {
 	StringValue bool
+	NoUnset     bool
+	NoEmpty     bool
 }
 
 func envOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
@@ -52,6 +54,7 @@ func envOperator(d *dataTreeNavigator, context Context, expressionNode *Expressi
 
 func envsubstOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
 	var results = list.New()
+	preferences := expressionNode.Operation.Preferences.(envOpPreferences)
 
 	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
 		candidate := el.Value.(*CandidateNode)
@@ -61,7 +64,7 @@ func envsubstOperator(d *dataTreeNavigator, context Context, expressionNode *Exp
 			return Context{}, fmt.Errorf("cannot substitute with %v, can only substitute strings. Hint: Most often you'll want to use '|=' over '=' for this operation", node.Tag)
 		}
 
-		value, err := envsubst.String(node.Value)
+		value, err := envsubst.StringRestricted(node.Value, preferences.NoUnset, preferences.NoEmpty)
 		if err != nil {
 			return Context{}, err
 		}

pkg/yqlib/operator_env_test.go

@@ -88,6 +88,29 @@ var envOperatorScenarios = []expressionScenario{
 			"D0, P[], (!!str)::the  meows\n",
 		},
 	},
+	{
+		description:          "Replace strings with envsubst(nu), missing variables",
+		environmentVariables: map[string]string{"myenv": "cat"},
+		expression:           `"the ${myenvnonexisting} meows" | envsubst`,
+		expected: []string{
+			"D0, P[], (!!str)::the  meows\n",
+		},
+	},
+	{
+		description:          "Replace strings with envsubst(ne), empty variable",
+		environmentVariables: map[string]string{"myenv": ""},
+		expression:           `"the ${myenv} meows" | envsubst`,
+		expected: []string{
+			"D0, P[], (!!str)::the  meows\n",
+		},
+	},
+	{
+		description: "Replace strings with envsubst(ne), missing variable",
+		expression:  `"the ${myenv} meows" | envsubst`,
+		expected: []string{
+			"D0, P[], (!!str)::the  meows\n",
+		},
+	},
 	{
 		description:          "Replace strings with envsubst, missing variables with defaults",
 		environmentVariables: map[string]string{"myenv": "cat"},