config/lang: completed type checking

config/lang/visitor_types.go

@@ -46,8 +46,31 @@ func (v *TypeVisitor) visit(raw ast.Node) {
 }
 
 func (v *TypeVisitor) visitCall(n *ast.Call) {
-	// TODO
-	v.stackPush(ast.TypeString)
+	// Look up the function in the map
+	function, ok := v.FuncMap[n.Func]
+	if !ok {
+		v.createErr(n, fmt.Sprintf("unknown function called: %s", n.Func))
+		return
+	}
+
+	// The arguments are on the stack in reverse order, so pop them off.
+	args := make([]ast.Type, len(n.Args))
+	for i, _ := range n.Args {
+		args[len(n.Args)-1-i] = v.stackPop()
+	}
+
+	// Verify the args
+	for i, expected := range function.ArgTypes {
+		if args[i] != expected {
+			v.createErr(n, fmt.Sprintf(
+				"%s: argument %d should be %s, got %s",
+				n.Func, i+1, expected, args[i]))
+			return
+		}
+	}
+
+	// Return type
+	v.stackPush(function.ReturnType)
 }
 
 func (v *TypeVisitor) visitConcat(n *ast.Concat) {

config/lang/visitor_types_test.go

@@ -46,6 +46,38 @@ func TestTypeVisitor(t *testing.T) {
 			false,
 		},
 
+		{
+			`foo ${rand("42")}`,
+			&TypeVisitor{
+				FuncMap: map[string]Function{
+					"rand": Function{
+						ArgTypes:   []ast.Type{ast.TypeString},
+						ReturnType: ast.TypeString,
+						Callback: func([]interface{}) (interface{}, error) {
+							return "42", nil
+						},
+					},
+				},
+			},
+			false,
+		},
+
+		{
+			`foo ${rand(42)}`,
+			&TypeVisitor{
+				FuncMap: map[string]Function{
+					"rand": Function{
+						ArgTypes:   []ast.Type{ast.TypeString},
+						ReturnType: ast.TypeString,
+						Callback: func([]interface{}) (interface{}, error) {
+							return "42", nil
+						},
+					},
+				},
+			},
+			true,
+		},
+
 		{
 			"foo ${bar}",
 			&TypeVisitor{
@@ -58,6 +90,21 @@ func TestTypeVisitor(t *testing.T) {
 			},
 			true,
 		},
+
+		{
+			"foo ${rand()}",
+			&TypeVisitor{
+				FuncMap: map[string]Function{
+					"rand": Function{
+						ReturnType: ast.TypeInt,
+						Callback: func([]interface{}) (interface{}, error) {
+							return 42, nil
+						},
+					},
+				},
+			},
+			true,
+		},
 	}
 
 	for _, tc := range cases {