Support builtins documentation and completions

Author: skovhus

server/src/__tests__/__snapshots__/builtins.test.ts.snap

@@ -0,0 +1,8 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`documentation returns documentation string an known builtin 1`] = `
+"exit: exit [n]
+    Exit the shell with a status of N.  If N is omitted, the exit status
+    is that of the last command executed.
+"
+`;

server/src/__tests__/builtins.test.ts

@@ -0,0 +1,13 @@
+import * as Builtins from '../builtins'
+
+describe('documentation', () => {
+  it('returns an error string an unknown builtin', async () => {
+    const result = await Builtins.documentation('foobar')
+    expect(result).toEqual('No help page for foobar')
+  })
+
+  it('returns documentation string an known builtin', async () => {
+    const result = await Builtins.documentation('exit')
+    expect(result).toMatchSnapshot()
+  })
+})

server/src/builtins.ts

@@ -0,0 +1,72 @@
+import * as ShUtil from './util/sh'
+
+export const LIST = [
+  '.',
+  ':',
+  '[',
+  'alias',
+  'bg',
+  'bind',
+  'break',
+  'builtin',
+  'caller',
+  'cd',
+  'command',
+  'compgen',
+  'complete',
+  'continue',
+  'declare',
+  'dirs',
+  'disown',
+  'echo',
+  'enable',
+  'eval',
+  'exec',
+  'exit',
+  'export',
+  'false',
+  'fc',
+  'fg',
+  'getopts',
+  'hash',
+  'help',
+  'history',
+  'jobs',
+  'kill',
+  'let',
+  'local',
+  'logout',
+  'popd',
+  'printf',
+  'pushd',
+  'pwd',
+  'read',
+  'readonly',
+  'return',
+  'set',
+  'shift',
+  'shopt',
+  'source',
+  'suspend',
+  'test',
+  'times',
+  'trap',
+  'true',
+  'type',
+  'typeset',
+  'ulimit',
+  'umask',
+  'unalias',
+  'unset',
+  'wait',
+]
+
+export async function documentation(builtin: string): Promise<string> {
+  const errorMessage = `No help page for ${builtin}`
+  try {
+    const doc = await ShUtil.execShellScript(`help ${builtin}`)
+    return doc || errorMessage
+  } catch (error) {
+    return errorMessage
+  }
+}

server/src/server.ts

@@ -1,6 +1,7 @@
 import * as LSP from 'vscode-languageserver'
 
 import Analyzer from './analyser'
+import * as Builtins from './builtins'
 import Executables from './executables'
 
 /**
@@ -159,10 +160,20 @@ export default class BashServer {
       }
     })
 
-    return symbolCompletions.concat(programCompletions)
+    const builtinsCompletions = Builtins.LIST.map(builtin => ({
+      label: builtin,
+      kind: LSP.SymbolKind.Method, // ??
+      data: {
+        name: builtin,
+        type: 'builtin',
+      },
+    }))
+
+    return [...symbolCompletions, ...programCompletions, ...builtinsCompletions]
   }
 
   private onCompletionResolve(item: LSP.CompletionItem): Promise<LSP.CompletionItem> {
+    // TODO: async await would be nice I guess
     if (item.data.type === 'executable') {
       return this.executables
         .documentation(item.data.name)
@@ -171,6 +182,14 @@ export default class BashServer {
           detail: doc,
         }))
         .catch(() => item)
+    } else if (item.data.type === 'builtin') {
+      //
+      return Builtins.documentation(item.data.name)
+        .then(doc => ({
+          ...item,
+          detail: doc,
+        }))
+        .catch(() => item)
     } else {
       return Promise.resolve(item)
     }