Production pass: floats, GC, type checking, and tooling

Adds floats, bitwise ops, UTF-8 strings with methods, try/catch,
closures, generics validation, a compile-time type checker, a
mark-and-sweep GC, source-level debug info, constant folding, and
the repl/fmt/package-manager commands.

🤖 Generated with Codebuff
Co-Authored-By: Codebuff <noreply@codebuff.com>

pkg.v

@@ -0,0 +1,151 @@
+// pkg.v — `vr init` / `vr get` / `vr install`: a minimal package manager.
+//
+// Packages are fetched into ./vendor/<name>/ and recorded in vr.mod as
+// `dep "<spec>"`. The compiler resolves `import "pkg/file"` against vendor/
+// automatically (see compiler/compiler.v). Supported package specs:
+//
+//   vr get owner/repo         clone from GitHub (https://github.com/owner/repo)
+//   vr get https://host/repo  clone any git repository
+//   vr get ./local/path       copy a local directory
+module main
+
+import os
+
+const manifest_file = 'vr.mod'
+const vendor_dir = 'vendor'
+
+fn toolchain_init(args []string) ! {
+	pkg := if args.len > 0 { args[0] } else { os.base(os.getwd()) }
+	if os.exists(manifest_file) {
+		return error('${manifest_file} already exists here')
+	}
+	os.write_file(manifest_file, 'module ${pkg}\nversion 0.1.0\n\n# deps:\n# dep "owner/repo"\n')!
+	os.mkdir('vendor') or {}
+	if !os.exists('main.vr') {
+		os.write_file('main.vr', 'fn main() {\n\tprintln("hello from ${pkg}")\n}\n')!
+	}
+	println('initialized project "${pkg}" (${manifest_file}, main.vr)')
+}
+
+fn toolchain_get(args []string) ! {
+	if args.len == 0 {
+		return error('usage: vr get <owner/repo | git-url | ./path>')
+	}
+	spec := args[0]
+	// determine the package name and how to fetch it
+	mut pkg := ''
+	if spec.starts_with('./') || spec.starts_with('/') {
+		pkg = os.base(spec)
+	} else if spec.contains('://') {
+		pkg = os.base(spec)
+	} else if spec.contains('/') {
+		pkg = spec.all_after('/')
+	} else {
+		pkg = spec
+	}
+	if pkg.ends_with('.git') {
+		pkg = pkg[..pkg.len - 4]
+	}
+	if pkg == '' || pkg == '.' {
+		return error('cannot derive a package name from "${spec}"')
+	}
+	os.mkdir(vendor_dir) or {}
+	dst := os.join_path(vendor_dir, pkg)
+	if os.exists(dst) {
+		return error('package "${pkg}" already exists at ${dst}')
+	}
+	if spec.starts_with('./') || spec.starts_with('/') {
+		copy_dir(spec, dst) or { return error('cannot copy ${spec}: ${err.msg()}') }
+	} else {
+		url := if spec.contains('://') { spec } else { 'https://github.com/${spec}.git' }
+		println('cloning ${url} -> ${dst} ...')
+		r := os.exec(['git', 'clone', '--depth', '1', url, dst])
+		if r.exit_code != 0 {
+			return error('git clone failed: ${r.output}')
+		}
+	}
+	// record the dependency in the manifest (idempotent)
+	if os.exists(manifest_file) {
+		manifest := os.read_file(manifest_file) or { '' }
+		if !manifest.contains('dep "${spec}"') {
+			os.write_file(manifest_file, manifest.trim_space() + '\ndep "${spec}"\n') or {
+				return error('cannot update ${manifest_file}: ${err.msg()}')
+			}
+		}
+	}
+	println('added package "${pkg}" (${spec})')
+}
+
+fn toolchain_install() ! {
+	if !os.exists(manifest_file) {
+		return error('no ${manifest_file} found — run `vr init` first')
+	}
+	manifest := os.read_file(manifest_file)!
+	mut n := 0
+	for line in manifest.split_into_lines() {
+		t := line.trim_space()
+		if !t.starts_with('dep "') {
+			continue
+		}
+		mut spec := t[5..]
+		if spec.ends_with('"') {
+			spec = spec[..spec.len - 1]
+		}
+		if spec == '' {
+			continue
+		}
+		n++
+		toolchain_get([spec]) or { eprintln('  install: ${err.msg()}') }
+	}
+	if n == 0 {
+		println('no dependencies in ${manifest_file}')
+		return
+	}
+	println('installed ${n} package(s) into ${vendor_dir}/')
+}
+
+// copy_dir recursively copies a local directory tree.
+fn copy_dir(src string, dst string) ! {
+	if !os.is_dir(src) {
+		return error('${src} is not a directory')
+	}
+	os.mkdir_all(dst) or { return error('cannot create ${dst}: ${err.msg()}') }
+	for entry in os.ls(src) or { return error('cannot read ${src}: ${err.msg()}') } {
+		sp := os.join_path(src, entry)
+		dp := os.join_path(dst, entry)
+		if os.is_dir(sp) {
+			copy_dir(sp, dp)!
+		} else if os.is_file(sp) {
+			os.cp(sp, dp, os.CopyParams{}) or { return error('cannot copy ${sp}: ${err.msg()}') }
+		}
+	}
+}
+
+fn toolchain_list() ! {
+	if !os.exists(manifest_file) {
+		return error('no ${manifest_file} found here')
+	}
+	manifest := os.read_file(manifest_file)!
+	mod_name := manifest.all_before('\n').replace('module ', '').trim_space()
+	println('project: ${mod_name}')
+	mut found := false
+	for line in manifest.split_into_lines() {
+		t := line.trim_space()
+		if t.starts_with('dep "') {
+			found = true
+			mut spec := t[5..]
+			if spec.ends_with('"') {
+				spec = spec[..spec.len - 1]
+			}
+			mut pkg := os.base(spec)
+			if pkg.ends_with('.git') {
+				pkg = pkg[..pkg.len - 4]
+			}
+			status := if os.exists(os.join_path(vendor_dir, pkg)) { 'installed' } else { 'missing' }
+			println('  ${pkg}  (${status})  <- ${spec}')
+		}
+	}
+	if !found {
+		println('  (no dependencies)')
+	}
+}