Added d:analyze and upgraded UCL

plugins.go

@@ -36,6 +36,7 @@ func (p *PluginFilters) Module() ucl.Module {
 		Name: "d",
 		Builtins: map[string]ucl.BuiltinHandler{
 			"filter":    p.filterBuiltin,
+			"analyze":   p.filterAnalyze,
 			"map-lines": p.mapLinesBuiltin,
 		},
 	}
@@ -80,6 +81,45 @@ func (p *PluginFilters) filterBuiltin(ctx context.Context, args ucl.CallArgs) (a
 	return nil, nil
 }
 
+// filterBuiltin implements `d:analyze LABEL PROC`. PROC receives the filter input as its only
+// argument and its result is displayed as the result in the status bar.
+func (p *PluginFilters) filterAnalyze(ctx context.Context, args ucl.CallArgs) (any, error) {
+	var (
+		label string
+		proc  ucl.Invokable
+	)
+
+	if err := args.Bind(&label, &proc); err != nil {
+		return nil, fmt.Errorf("d:analyze: expected LABEL and PROC: %w", err)
+	}
+	if strings.TrimSpace(label) == "" {
+		return nil, errors.New("d:analyze: label must not be empty")
+	}
+	if proc.IsNil() {
+		return nil, errors.New("d:analyze: PROC must not be nil")
+	}
+
+	p.filters[pluginKeyPrefix+slugify(label)] = TextProcessor{
+		Label: label,
+		Analyze: func(ctx context.Context, input string) (string, error) {
+			res, err := proc.Invoke(ctx, input)
+			if err != nil {
+				return "", err
+			}
+
+			switch v := res.(type) {
+			case nil:
+				return "", errors.New("filter returned no value")
+			case string:
+				return v, nil
+			default:
+				return fmt.Sprint(v), nil
+			}
+		},
+	}
+	return nil, nil
+}
+
 // mapLinesBuiltin implements `d:map-lines INPUT PROC` which applies a transform for each line of the input.
 func (p *PluginFilters) mapLinesBuiltin(ctx context.Context, args ucl.CallArgs) (any, error) {
 	var (