Research: Port Fish shell to meniOS

[pbalduino]

Context

Evaluate feasibility of porting Fish (Friendly Interactive Shell) to meniOS.

Important Discovery

Fish 4.0+ is now written in Rust (no longer C++), which significantly changes the porting strategy.

Fish Requirements Analysis

Language Requirements

• Rust compiler (rustc + cargo)
• Rust standard library
• Or: Fish 3.x (C++ version) - deprecated

System Dependencies

Fish requires these POSIX utilities:

• Core: cat, cut, dirname, ls, mkdir, rm, sort, tr, uname, sed
• Preferred: Full coreutils, find, awk
• For help: man pages
• For config: Python 3.5+

meniOS Prerequisites

For Rust Fish (4.0+)

• [ ] Rust compiler port to meniOS (very large undertaking)
• [ ] Rust std library port
• [ ] All POSIX utilities (#183 is just basic ones)
• [ ] Threading (#109-111)
• [ ] Signals (#103)
• [ ] Pipes (#102)
• [ ] Terminal control (termios)
• [ ] File write support (#189)
• [ ] Job control

For C++ Fish (3.x - deprecated)

• [ ] C++ compiler support
• [ ] libstdc++ or libc++
• [ ] Same system requirements as above

Difficulty Assessment

Modern Fish (Rust): 10/10 - Extremely difficult

• Requires entire Rust toolchain
• Rust is harder to port than C/C++
• Still in active development

Legacy Fish (C++): 9/10 - Very difficult

• Deprecated version
• Still needs C++ support
• Complex codebase

Recommendation Path

Short Term (Current)

Focus on shell milestone - simple, C-based, meniOS-native

Medium Term (6-12 months)

1. Complete cross-compiler toolchain (#29)
2. Implement IPC primitives (#102-104)
3. Build comprehensive utilities (#183, #187, #188)
4. Consider: Build Fish-inspired shell in C for meniOS
   • Take Fish's best UX ideas
   • Implement in portable C
   • Design for meniOS from the ground up
   • Much more realistic than porting

Long Term (12-24 months)

1. Add C++ support to toolchain
2. Port simpler shells (dash, ash)
3. Possibly attempt Fish 3.x (C++ version)
4. Or: Port minimal Rust runtime + Fish 4.x

Alternative: meniOS-native Modern Shell

Instead of porting Fish, create fiOS (Fish-inspired OS shell):

• Written in C (works with current toolchain)
• Fish-like features: syntax highlighting, autosuggestions, tab completion
• Designed for meniOS constraints
• Lightweight and fast
• Can iterate quickly

Benefits

• No dependency hell
• Educational value (learn shell design)
• Optimized for meniOS
• Can ship sooner

Timeline Estimates

• Port Rust Fish: 24+ months (requires Rust toolchain port)
• Port C++ Fish 3.x: 18-24 months (requires C++ support)
• Build Fish-inspired shell: 6-12 months (after #29 complete)

Recommendation

Don't port Fish directly. Instead:

1. Finish for basic shell milestone
2. Build a Fish-inspired modern shell in C
3. Implement Fish's best features gradually
4. Keep it meniOS-native and maintainable