node.go

@@ -204,13 +204,10 @@ func jsonKind(v any) string {
 }
 
 func compileString(s string) (node, error) {
-	toks, err := parseFormat(s)
+	toks, err := parseChecked(s, nil)
 	if err != nil {
 		return nil, err
 	}
-	if err := checkTokens(toks, nil); err != nil {
-		return nil, err
-	}
 	t := &template{format: s, tokens: toks, repeat: 1, fromString: true}
 	if err := t.compileRefFree(); err != nil {
 		return nil, err
@@ -336,13 +333,10 @@ func compileTemplate(m map[string]any, pos position) (node, error) {
 	if len(fields) == 0 && o.repeat == 1 && !o.weighted && o.datatype == DataTypeString && o.group == "" {
 		return nil, fmt.Errorf("an object holding only a format is a string; write %q", o.format)
 	}
-	toks, err := parseFormat(o.format)
+	toks, err := parseChecked(o.format, fields)
 	if err != nil {
 		return nil, err
 	}
-	if err := checkTokens(toks, fields); err != nil {
-		return nil, err
-	}
 	if err := checkNestedDrawGroup(fields, o.group); err != nil {
 		return nil, err
 	}

template.go

@@ -185,6 +185,14 @@ func checkFunc(tok formatToken, fields map[string]node) error {
 	return nil
 }
 
+func parseChecked(format string, fields map[string]node) ([]formatToken, error) {
+	toks, err := parseFormat(format)
+	if err != nil {
+		return nil, err
+	}
+	return toks, checkTokens(toks, fields)
+}
+
 // checkTokens proves every parsed token names an existing field or a known function,
 // so a typo'd or dangling reference is a New-time error.
 func checkTokens(toks []formatToken, fields map[string]node) error {