watch

Documentation

Overview

Package watch is the host-side half of `m watch` (spec §3.1, §9): a save triggered inner loop that re-runs the engine-neutral checks (lint, fmt) on changed files. The run half (compile/test/coverage) is a later, engine-bound stage (4.2) — this package never executes M.

It polls file signatures rather than using inotify/fsnotify, keeping the dependency footprint at zero (minimal-SBOM posture) and staying trivially cross-platform. Polling a dev working set is cheap; fsnotify is a possible future optimization for very large trees.

Index

• type Event
• type Lister
• type Watcher
  • func (w *Watcher) Watch(ctx context.Context, emitBaseline bool, onChange func(Event)) error

Types

type Event

type Event struct {
	Changed []string // created or modified
	Removed []string
}

Event reports the files that changed since the previous scan.

type Lister

type Lister func() ([]string, error)

Lister returns the current set of files to watch (re-evaluated each scan, so newly created files are picked up).

type Watcher

type Watcher struct {
	List     Lister
	Interval time.Duration
}

Watcher polls the files from List every Interval and reports changes.

func (*Watcher) Watch

func (w *Watcher) Watch(ctx context.Context, emitBaseline bool, onChange func(Event)) error

Watch scans a baseline, then polls until ctx is done, calling onChange for each non-empty event. If emitBaseline is set, the initial file set is delivered as one Changed event first (so startup checks everything). It returns ctx.Err() when ctx is canceled.