Add activateOnCompletion option

FEATURE: The new `activateOnCompletion` option allows autocompletion to be configured
to chain completion activation for some types of completions.

Issue https://discuss.codemirror.net/t/how-to-invoke-autocomplete-immediately-after-a-completion-is-selected/8040

src/config.ts

@@ -7,6 +7,9 @@ export interface CompletionConfig {
   /// When enabled (defaults to true), autocompletion will start
   /// whenever the user types something that can be completed.
   activateOnTyping?: boolean
+  /// When given, if a completion that matches the predicate is
+  /// picked, reactivate completion again as if it was typed normally.
+  activateOnCompletion?: (completion: Completion) => boolean
   /// The amount of time to wait for further typing before querying
   /// completion sources via
   /// [`activateOnTyping`](#autocomplete.autocompletion^config.activateOnTyping).
@@ -93,6 +96,7 @@ export const completionConfig = Facet.define<CompletionConfig, Required<Completi
   combine(configs) {
     return combineConfig<Required<CompletionConfig>>(configs, {
       activateOnTyping: true,
+      activateOnCompletion: () => false,
       activateOnTypingDelay: 100,
       selectOnOpen: true,
       override: null,

src/state.ts

@@ -186,7 +186,11 @@ const none: readonly any[] = []
 
 export const enum State { Inactive = 0, Pending = 1, Result = 2 }
 
-export function getUserEvent(tr: Transaction): "input" | "delete" | null {
+export function getUserEvent(tr: Transaction, conf: Required<CompletionConfig>): "input" | "delete" | null {
+  if (tr.isUserEvent("input.complete")) {
+    let completion = tr.annotation(pickedCompletion)
+    if (completion && conf.activateOnCompletion(completion)) return "input"
+  }
   return tr.isUserEvent("input.type") ? "input" : tr.isUserEvent("delete.backward") ? "delete" : null
 }
 
@@ -198,7 +202,7 @@ export class ActiveSource {
   hasResult(): this is ActiveResult { return false }
 
   update(tr: Transaction, conf: Required<CompletionConfig>): ActiveSource {
-    let event = getUserEvent(tr), value: ActiveSource = this
+    let event = getUserEvent(tr, conf), value: ActiveSource = this
     if (event)
       value = value.handleUserEvent(tr, event, conf)
     else if (tr.docChanged)

src/view.ts

@@ -82,10 +82,11 @@ export const completionPlugin = ViewPlugin.fromClass(class implements PluginValu
 
   update(update: ViewUpdate) {
     let cState = update.state.field(completionState)
+    let conf = update.state.facet(completionConfig)
     if (!update.selectionSet && !update.docChanged && update.startState.field(completionState) == cState) return
 
     let doesReset = update.transactions.some(tr => {
-      return (tr.selection || tr.docChanged) && !getUserEvent(tr)
+      return (tr.selection || tr.docChanged) && !getUserEvent(tr, conf)
     })
     for (let i = 0; i < this.running.length; i++) {
       let query = this.running[i]
@@ -104,12 +105,12 @@ export const completionPlugin = ViewPlugin.fromClass(class implements PluginValu
 
     if (this.debounceUpdate > -1) clearTimeout(this.debounceUpdate)
     if (update.transactions.some(tr => tr.effects.some(e => e.is(startCompletionEffect)))) this.pendingStart = true
-    let delay = this.pendingStart ? 50 : update.state.facet(completionConfig).activateOnTypingDelay
+    let delay = this.pendingStart ? 50 : conf.activateOnTypingDelay
     this.debounceUpdate = cState.active.some(a => a.state == State.Pending && !this.running.some(q => q.active.source == a.source))
       ? setTimeout(() => this.startUpdate(), delay) : -1
 
     if (this.composing != CompositionState.None) for (let tr of update.transactions) {
-      if (getUserEvent(tr) == "input")
+      if (getUserEvent(tr, conf) == "input")
         this.composing = CompositionState.Changed
       else if (this.composing == CompositionState.Changed && tr.selection)
         this.composing = CompositionState.ChangedAndMoved