WebBase-III: A Modern Browser-Based Reimagining of dBASE III

Before the era of SQL dominance, ORMs, and the concept of "full-stack" development, there was dBASE III. It was a world where a simple USE customers followed by a LIST command gave you immediate access to your data.

WebBase-III resurrects this experience. It is a comprehensive reconstruction of the dBASE III ecosystem—including the terminal, the specialized language, the BROWSE utility, @ SAY GET form layouts, .prg scripting, indexing, and reporting. This is not a mere emulation but a modern web application featuring a custom interpreter written in TypeScript, powered by Node.js, WebSockets, and SQLite.

🛠️ System Architecture

The application operates through a client-server model where the interpreter manages the state for each user session.

🌟 Key Capabilities

🖥️ The Terminal & REPL

The heart of the app is the command interface. By typing W3Script, users get instantaneous feedback.

LIST: Displays records in a tabular format based on the current active index.
Indexing: Using INDEX ON name TO BYNAME generates a SQLite index. This ensures that subsequent LIST calls are sorted alphabetically.
SEEK: Allows the user to jump to a specific record (e.g., SEEK "Delta NV") with a time complexity of $\mathcal{O}(\log n)$ .

📊 Data Interaction

BROWSE: Launches an interactive, spreadsheet-like grid.
- Navigation: Use Tab or Enter to modify cells.
- Management: Ctrl+N adds a row; Delete removes one.
- Exit: Press Esc to return to the command line.
Program Editor: The EDIT name command opens a built-in editor for .prg files. These scripts support full logic: DO CASE/ENDCASE, DO WHILE/ENDDO, IF/ENDIF, and complex data operations.

📝 Form Engine

WebBase-III implements the classic character-cell layout system:

Layout: @ row,col SAY "label" GET variable defines the field positions.
Execution: The READ command transforms these definitions into a live, interactive form for user input.

🤖 The Assistant

A persistent sidebar provides a GUI layer to the system. It allows users to manage databases, filter data, and design reports without typing.

Educational Loop: Every GUI action triggers a corresponding W3Script command in the terminal, teaching the user the language in real-time.
Wizards: Tools for creating tables or modifying structures appear in the main window with a live preview of the generated code.

📋 Feature Summary

Feature	Technical Detail
W3Script Interpreter	Supports dBASE III dialect: loops, conditionals, and navigation.
BROWSE Grid	Inline editing with keyboard navigation and index-based sorting.
Form Engine	`@ ROW,COL` layout system triggered by the `READ` command.
Indexing	`INDEX ON`, `SEEK`, and `FIND` for record pointer control.
Logic	`DO CASE` with `OTHERWISE` fallbacks for multi-branching.
Built-in Functions	`EOF()`, `BOF()`, `FOUND()`, `RECNO()`, `SUBSTR()`, `STR()`, `AT()`, `CTOD()`, `DTOC()`, etc.
Scripting	`.prg` files managed via `DO` and `EDIT`.
The Assistant	Sidebar for GUI-driven DB management and report design.
Concurrency	Multi-user support via isolated WebSocket interpreter sessions.
Persistence	`better-sqlite3` with WAL mode ensures data survives restarts.

🚀 Getting Started

Installation Checklist

Install Node.js
Clone the repository
Run npm install

Execution Commands

To start the environment, use the following:

Development Mode:

npm run dev
# Access via http://localhost:5173

Production Mode:

npm run serve
# Builds and serves on http://localhost:3000

Note: The server binds to 0.0.0.0, making it compatible with LAN or Tailscale IPs (e.g., http://tailscale-ip:3000).

💻 Example Session

USE DATABASE mydb
CREATE TABLE customers (name CHAR(40), phone CHAR(20), country CHAR(30))
USE customers
APPEND RECORD REPLACE name WITH "Acme Corp", phone WITH "555-1234", country WITH "BE"
APPEND RECORD REPLACE name WITH "Zeta Ltd", phone WITH "555-5678", country WITH "NL"
INDEX ON name TO BYNAME
LIST               -- Output is now sorted A→Z
SEEK "Zeta Ltd"    -- Instant jump to record
BROWSE             -- Open the editable grid
SET FILTER TO country == "BE"
LIST               -- Only Belgian customers shown
SET FILTER TO      -- Clear the filter

📖 W3Script Reference

Work Areas

WebBase-III supports an unlimited number of work areas (~~unlike the original dBASE III, which was limited to 10 due to DOS file handles~~). Each area maintains its own:

Table
Record pointer
Filter
Index

Relational Data: Use SET RELATION TO to link work areas via key fields for automatic seeking during navigation.

Syntax Note: While dBASE III used alias->field (arrow syntax), WebBase-III adopts the modern alias.field (dot notation).

Common Commands

Command	Description
`SELECT alias`	Activates or creates a specific work area.
`USE table [ALIAS name]`	Opens a table in the active area (optional alias).
`SET RELATION TO expr INTO alias`	Links the active area to another; auto-seeks on move.
`SET RELATION TO`	Removes the relation from the active area.
`LIST [col]`	Displays records in the current area.