I've spent a good portion of the past year learning how to deconstruct, modify, and then reconstruct Sierra On-Line's AGI adventure games. With the right tools, it is not too difficult to change the appearance of a background picture or an inventory object's image. Tweaking the occasional image makes for a fun experiment, but the true magic comes from altering the underlying logic of the game to provide additional functionality.
The AGI games were developed using a custom scripting language called LOGIC. One of the interesting side effects of modifying a LOGIC source file in AGI Studio for Mac is that it saves out a copy of the file (e.g. logic.045) into the project's src directory. Unfortunately, the text editor in AGI Studio is quite simplistic and doesn't work too well. Fortunately, one can directly edit the LOGIC files stored in the src directory using their preferred text editor, instead of editing the source file directly inside AGI Studio. Once I discovered I could use an external text editor to modify the LOGIC files, that became my standard workflow. (Note: the code still needs to compiled within AGI Studio, but it will read in any changes to the saved files in the src directory.)
One downside to working with an old, obscure, and proprietary language such as LOGIC is that modern day text editors will likely not know how to properly provide syntax coloring. Fortunately, there is a way to work around this issue in BBEdit by creating a Codeless Language Module. I had recently encountered a similar issue when reading a C# file on a Mac, which prompted me to learn about the Codeless Language Modules in BBEdit. After doing some research, I learned that it was very feasible to design my own module for AGI LOGIC. Below is the current version of the AGI LOGIC Codeless Language Module for BBEdit.
To install, download and unzip the agi-logic.plist file and copy it into the ~/Library/Application Support/BBEdit/Language Modules/ directory on your Mac.
When editing a LOGIC source file in BBEdit, select AGI LOGIC as the Document Language setting from the bottom of the window, which will enable syntax coloring and the ability to quickly (un)comment lines and blocks of code.
References
- Codeless Language Module Reference
- Language Module Documentation Supplement
- Codeless Language Modules - BBEditExtras
- BBEdit Language Module Library
- Building a Codeless Language Module with BBEdit 8.5 and (Ir-)Regular Expressions
- BBEdit Codeless Language Module for Swift
- ChoiceScript language module for TextWrangler
- Igor Pro Language Module for use in BBEdit
- Go Codeless Language Module
- BBEdit Codeless Language Module for TypeScript