Geir O. Jerstad
646c8bbc20
- Split complex nested functions into focused, single-responsibility helpers - Created io/ directory with pure command builders and impure executors - Eliminated parentheses complexity that was causing compilation errors - SSH module now compiles and runs successfully with cleaner architecture 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com>
2.9 KiB
2.9 KiB
Lab Tool Refactoring Plan - Functional Programming Approach
Current Problems
- Deep nested parentheses causing syntax errors
- Functions doing too many things
- Hard to debug and maintain
- Mixed pure/impure logic
New Structure
lab-tool/
├── core/
│ ├── config.scm # Pure config access
│ ├── machine.scm # Pure machine data structures
│ └── commands.scm # Pure command building
├── io/
│ ├── ssh.scm # Pure SSH command building
│ ├── rsync.scm # Pure rsync command building
│ └── shell.scm # Impure shell execution
├── deploy/
│ ├── ssh-strategy.scm # Pure deployment strategy
│ ├── deploy-rs-strategy.scm # Pure deploy-rs strategy
│ └── executor.scm # Impure deployment execution
├── health/
│ ├── checks.scm # Pure health check logic
│ └── monitor.scm # Impure health monitoring
└── main/
├── cli.scm # Pure CLI parsing
├── dispatcher.scm # Pure command dispatch
└── runner.scm # Impure main execution
Functional Principles
1. Single Responsibility Functions
;; Instead of one complex function doing everything:
(define (deploy-complex machine options) ...)
;; Break into focused functions:
(define (build-rsync-command source dest ssh-config) ...)
(define (build-nixos-rebuild-command flake-path machine mode) ...)
(define (execute-command command) ...)
(define (compose-ssh-deployment rsync-cmd rebuild-cmd) ...)
2. Pure vs Impure Separation
;; Pure: No side effects, testable
(define (make-ssh-target user hostname)
(format #f "~a@~a" user hostname))
;; Impure: Clear side effects
(define (execute-ssh-command ssh-config command)
(system (build-ssh-command ssh-config command)))
3. Function Composition
;; Instead of deep nesting:
(let ((config (get-ssh-config machine))
(command (build-command ...))
(result (execute (format ...))))
(if (success? result) ...))
;; Use composition:
(-> machine
get-ssh-config
(build-deployment-commands flake-path)
execute-deployment
handle-result)
4. Error Handling as Values
;; Instead of exceptions in nested calls:
(catch #t (lambda () (complex-nested-operation)) error-handler)
;; Return result types:
(define (safe-ssh-connect machine)
(if (valid-config? machine)
`(success . ,(make-connection machine))
`(error . "Invalid SSH config")))
Implementation Steps
- Extract SSH utilities (no more parentheses hell)
- Create pure command builders
- Separate execution layer
- Build composable deployment strategies
- Clean CLI interface
This will make debugging much easier - each small function can be tested independently!