THelpViewer

A web-based viewer for Borland/Turbo Pascal and Software602 help files, rendered as a TurboVision-style single-page application.

Homepage: https://thelp.zdrojak.dev

Reads binary .HLP, .TPH, .TCH and text .hlx help files and serves them as an interactive web application with authentic DOS look and feel.

Supported Formats

Format	Products	Extension
Borland THELP	Turbo Pascal 4–7, Turbo C, TASM, Sidekick, Sprint	.HLP, .TPH, .TCH
TurboVision FBHF	Turbo Vision apps (TP6, BP7), TVHC compiler	.HLP
Software602 M602	M602 Manager (XOR $FA encrypted)	.HLP
Software602 Text602	Text602, Calc602 word processors	.HLP
HLX/HL6 text	Decompiled text format (round-trip capable)	.hlx, .hl6

Quick Start

Local

# 1. Download help files from the internet (requires 7z)
./thelp.sh download

# 2. Build compressed .json.gz bundles from source help files
./thelp.sh build

# 3. Serve locally
./thelp.sh serve

Or do everything at once (download + build + Docker):

./thelp.sh all

Open http://localhost:5448 in your browser. Port 5448 = 0x5448 = ASCII "TH" (THelp).

Docker

docker compose up --build

This builds all help files and starts a web server on http://localhost:8080.

Project Structure

THelpViewer/
├── converter/              ← Python converter package
│   ├── readers/            ←   format readers (thelp, fbhf, hlx, m602)
│   ├── writers/            ←   output writers (html, js/json.gz, md)
│   ├── assets/             ←   TurboVision CSS, JS (core, highlight, dialogs, shell, app)
│   ├── base.py             ←   shared data model (HelpDocument, TopicRecord, …)
│   ├── codepages.py        ←   encoding tables (CP437, CP852, Kamenický)
│   └── exporter.py         ←   high-level export orchestration
├── downloader/             ← Help file downloader (WinWorldPC, archive.org, old-dos.ru)
├── sources/                ← Source help files organized by product group
│   ├── Borland Turbo Pascal 7/   ← e.g. TURBO.TPH, TVISION.TPH, OWL.TPH
│   ├── Borland Turbo C 2.01/     ← e.g. TCHELP.TCH
│   └── …
├── www/                    ← Generated output
│   ├── index.html          ←   SPA viewer entry point
│   ├── helps/              ←   compressed .json.gz bundles + catalog.json
│   ├── docs/               ←   Markdown docs served in-viewer
│   └── assets/             ←   CSS + JS assets
├── docs/                   ← Documentation
│   ├── FORMATS.md          ←   binary format index
│   ├── Formats/            ←   detailed format specifications
│   │   ├── Borland THELP.md
│   │   ├── TurboVision FBHF.md
│   │   ├── Software602.md
│   │   ├── Software602 M602.md
│   │   ├── Software602 Text602.md
│   │   └── Help Source Text Format.md
│   └── THelp Viewer/       ←   viewer and tool docs
│       ├── Bundle.md       ←   JSON bundle transport format
│       ├── Converter.md    ←   converter usage & architecture
│       ├── Downloader.md   ←   help file downloader
│       └── TurboVision JS.md ← JS UI framework API
├── thelp.sh                ← Build, serve & manage script
├── Dockerfile
└── docker-compose.yml

Features

• Authentic TurboVision UI — menus, windows, scrollbars, dialogs, resize, maximize
• Compressed bundles — native gzip .json.gz bundles (70–80% size reduction)
• Loading progress — DOS Navigator-style dialog with progress bar and Cancel
• Full-text search — search across all topics within a help file
• A–Z index navigation — letter jump links in the index view
• Window management — zoom (F5), close (Alt-F3), drag, resize
• Theme support — light, dark, auto (system preference)
• Color customization — TurboVision Colors dialog with live preview
• Syntax highlighting — Pascal, C, and ASM highlighting (client-side)
• Code block heuristic — automatic detection for older formats without markers (TC 2.0/2.01)
• Built-in apps — Calculator, ASCII table, Calendar, Tetris, Minesweeper, Puzzle

How It Works

1. The downloader (python3 -m downloader) fetches original help files from WinWorldPC, archive.org, and old-dos.ru into sources/
2. thelp.sh build runs the converter over all files in sources/
3. Each help file is parsed and rendered into a JSON bundle containing pre-rendered HTML for every topic, index entries, and search data
4. The JSON is gzip-compressed into a .json.gz file
5. A catalog.json and index.html are generated for the SPA viewer
6. The browser fetches bundles on demand, decompresses via DecompressionStream, and renders them in a TurboVision window

See Bundle format for the JSON bundle specification.

To build and serve in one step:

./thelp.sh build serve

To serve only (if bundles are already built):

./thelp.sh serve

After regeneration, restart the server/Docker and hard-refresh the browser (Ctrl+F5).

Documentation

Format Specifications

• Format index — overview and comparison of all binary formats
• Borland THELP — TP4–7, Turbo C, TASM, Sidekick, Sprint
• TurboVision FBHF — TP6, BP7 THelpFile (TVHC compiler)
• Software602 — M602, Text602, Calc602 help families
• Help source text format — HLX/TXT decompiled-source specification

Viewer & Tools

• Converter — help file converter (binary → HTML / JSON / Markdown)
• JSON Bundle format — transport format for the SPA viewer
• Downloader — automated help file downloader
• TurboVision JS — JavaScript UI framework API reference

Requirements

• Python 3.10+ (no external dependencies)
• Modern browser with DecompressionStream API support
• Docker (optional, for containerized deployment)

License

This project is licensed under the GNU General Public License v3.0.

Bundled Fonts

The bitmap fonts in converter/assets/fonts/ are from The Ultimate Oldschool PC Font Pack by VileR, licensed under CC BY-SA 4.0.