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Pascal Script: Overview

The Pascal Script rule in ReNamer allows advanced users to create custom renaming logic using a scripting language based on Pascal/Delphi syntax. This provides full programmatic control over filenames, paths, metadata, and file system operations, making it ideal for complex tasks that standard rules cannot handle easily.

A collection of specialized functions and extensions makes scripting particularly powerful for Unicode filename handling, dynamic meta tag extraction, file system interactions, and integrating external data or tools.

If you're new to scripting or programming, start with the Basics to learn the fundamentals step by step, and then explore the Examples. The following sections provide reference details once you're comfortable with the fundamentals.

Key concepts

  • Script Execution: Scripts are executed during the Preview stage just like other renaming rules, allowing you to manipulate the new name for every processed file.
  • Main Variable: The core of most scripts is the FileName variable of type WideString, which represents the new basename with extension. Modify this variable to change the new name for a file.
  • Path Access: The FilePath constant provides the full original path to the file, allowing direct file system operations, like reading content, applying external tools, etc.
  • Unicode Support: ReNamer's implementation uses WideString as the primary string type for full Unicode compatibility, supporting non-English characters and international scripts.

Extensions and functions

ReNamer extends the standard Pascal Script engine with custom types and functions tailored for renaming tasks, including:

  • Wide-string variants of common functions, e.g. WideUpperCase, WideReplaceStr.
  • File utilities, e.g. WideFileExists, FileReadTextLines.
  • Meta tag extraction via CalculateMetaTag.
  • Support for user-defined functions (UDFs) and importing external functions from DLLs.
  • Include directive {$INCLUDE 'filename.inc'} for reusing code from external files (available since v6.5.0.1 Beta).

Best practices

Follow these recommendations for reliable, efficient scripts:

  • Always prefer WideString over String for paths and names to ensure Unicode compatibility.
  • Avoid overriding built-in variables, types, or functions.
  • Some functions can modify the file system (e.g. create folders, delete files), use these with caution.
  • Test scripts thoroughly in Preview mode.
Warnings
  • Scripts execute on every preview, which can impact performance with large file lists or heavy operations.
  • If auto preview options are enabled, scripts can be triggered automatically on any change to rules or files, which may cause unintended repeated execution — particularly relevant for scripts that perform file system operations.
  • Infinite loops or errors can freeze ReNamer, include safeguards like counters where needed.
  • File system changes in scripts are immediate and irreversible.

Further reading

These articles will help you learn and master the power of Pascal Script:

  • Basics – Syntax fundamentals, control structures, and quick start guide.
  • Types – Data types and structures.
  • Functions – Full reference of built-in functions.
  • Examples – Educational snippets and how-tos.
  • Library – Curated, ready-to-use scripts for common tasks and integrations with 3rd party tools.

You can also find examples, discussions and user contributed scripts on the User Forum.

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