pkgx uninstall

Fixes #752; Refs #788

src/modes/install.ts

@@ -24,13 +24,20 @@ export default async function(pkgs: PackageRequirement[]) {
 
   async function write(dst: Path, pkgs: PackageRequirement[]) {
     for (const pkg of pkgs) {
+      program_loop:
       for (const program of await usePantry().project(pkg).provides()) {
 
         // skip for now since we would require specific versions and we haven't really got that
         if (program.includes("{{")) continue
 
         const pkgstr = utils.pkg.str(pkg)
         const exec = `exec pkgx +${pkgstr} -- ${program} "$@"`
+        const script = undent`
+          if [ "$PKGX_UNINSTALL" != 1 ]; then
+            ${exec}
+          else
+            rm "$0" && echo "uninstalled: $0" >&2
+          fi`
         const f = dst.mkdir('p').join(program)
 
         if (f.exists()) {
@@ -44,21 +51,23 @@ export default async function(pkgs: PackageRequirement[]) {
           if (shebang != "#!/bin/sh") {
             throw new PkgxError(`${f} already exists and is not a pkgx installation`)
           }
-          const { value } = await lines.next()
-          if (value == exec) {
-            console.warn(`pkgx: already installed: ${blurple(program)} ${dim(`(${pkgstr})`)}`)
-            n++
-            continue
-          }
-          if (!value.startsWith('exec pkgx')) {
-            throw new PkgxError(`${f} already exists and is not a pkgx installation`)
+          while (true) {
+            const { value, done } = await lines.next()
+            if (value == exec) {
+              console.warn(`pkgx: already installed: ${blurple(program)} ${dim(`(${pkgstr})`)}`)
+              n++
+              continue program_loop
+            }
+            if (done) {
+              throw new PkgxError(`${f} already exists and is not a pkgx installation`)
+            }
           }
         }
 
         f.write({ force: true, text: undent`
           #!/bin/sh
-          ${exec}
-          ` }).chmod(0o755)
+          ${script}`
+        }).chmod(0o755)
         console.error('pkgx: installed:', f)
         n++
       }

src/modes/uninstall.ts

@@ -0,0 +1,13 @@
+import parse_pkg_str from "../prefab/parse-pkg-str.ts"
+
+export default async function(pkgspecs: string[]) {
+  const pkgs = await Promise.all(pkgspecs.map(x => parse_pkg_str(x, {latest: 'ok'})))
+
+  for (const pkg of pkgs) {
+    if (pkg.project == 'pkgx.sh') {
+      uninstall_self()
+    } else {
+
+    }
+  }
+}

src/parse-args.ts

@@ -35,7 +35,7 @@ export type Args = {
     mode: 'internal.activate'
     dir: Path
   } | {
-    mode: 'install'
+    mode: 'install' | 'uninstall'
     args: string[]
   }
 )
@@ -60,6 +60,7 @@ export default function(input: string[]): Args {
   switch (input[0]) {
   case 'deintegrate':
   case 'integrate':
+  case 'uninstall':
   case 'install':
   case 'run':
     mode = input[0]