dvlsh - Dievilz Shell

🧭 Core Philosophy

Grug like Unix philosophy, Grug want to spread it so world be better place, Grug remain hopeful.

• POSIX-compliant, Ksh-compatible shell
• Written entirely in Zig ⚡️, with modules designed to be cleanly testable and maintainable
• Clear separation between core shell, plugins, CLI, configuration, and runtime state
• Support for several config file formats, may end up just supporting one lol
• Built-in plugin API so if a feature is wanted, it can be added quickly.
• Emphasis on interactive shell UX: modern prompt, autosuggestions, syntax highlighting, and more
• Always ready for customization. New prompt? Just type :reload-prompt... New session behavior? Just type :reload-config
• Live session monitoring on demand. No more subshells for debugging/tracing
• No fallback or automatic behaviors: user must opt-in explicitly to advanced features

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🧱 Architecture Draft

src/
├── main.zig
├── shell/            → Shell lifecycle, executor, session, job control
├── input/            → Editor, keymaps, autosuggest, history
├── output/           → Prompt, themes, ANSI control
├── parser/           → Lexer, parser, AST
├── builtins/         → cd, set, trace, jobs, etc.
├── config/           → Loader, schema, registry, multiple format support
│   └── format/       → zigrc.zig, gitstyle.zig
├── core/             → Env, vars, shellcontext, hooks
├── posix/            → Signal handling, redirection, fds
├── util/             → str.zig, io.zig, fs.zig
├── plugins/          → registry.zig, api.zig
└── test/             → Unit + integration tests

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🔩 Config System

• Supports multiple formats: Zig DSL, JSON, Git-style
• Provenance tracking: every config entry tagged with source (default, user, plugin)
• Reloading must be explicitly triggered by user (:reload-config) — no live file-watching.

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🧠 Script & Function Layer

• POSIX scripting is the only supported script language for now
• POSIX scripts can use shell-defined functions
• No separation between POSIX and non-POSIX behavior for now — design must remain coherent.

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⚠️ Error Handling & Diagnostics

• POSIX set options supported: -e, -u, -x
• Add :trace command for live session tracing
• Errors should clearly display filename and context
• Tracing should be enabled on demand, not just at shell startup.

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🔌 Plugin System

• Users do not need to write Zig for plugins — secondary language planned (TBD)
• Plugins may override or extend default behavior
• Features baked into shell but overridable:
  1. Prompt customization
  2. Syntax highlighting
  3. Autosuggestions
  4. History substring completion
  5. Command completion support and more.

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💡 UX Innovations

Fixed Prompt Zone / Transient Prompt

• Prompt is always rendered at the bottom of the terminal
• Older prompts remain in scrollback with different visuals
• Prompt redraws cleanly (not reflows) on window resize* (May just leave it to Ghostty?)
• Prompt zone and buffer zone are clearly separated
• Feature must be explicitly enabled — no automatic fallback in tmux or multiplexers

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🔎 Traceability & Live Monitoring

• dvlsh will expose internal shell state (env, config, vars, history, trace logs)
• Users can inspect this live during a session or via external tools (e.g. Ghostty Inspector)
• Mechanism:
  • UNIX domain socket-based stream (initial)
  • Optional: Plan 9-style virtual FS (e.g. /tmp/dvlsh-inspect/config/PATH)
  • Future: experimental 9P protocol interface

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✅ Confirmed Milestones Implemented

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Author's note

This is a POC so I can learn Zig and systems programming, sounds like the ultimate learning project at that but I can accept the challenge 😅.