feat: support multiple previewers

Author: lambdalisue

denops/fall/event.ts

@@ -27,6 +27,8 @@ export type Event =
   | { type: "switch-sorter-at"; index: number | "$" }
   | { type: "switch-renderer"; amount: number; cycle?: boolean }
   | { type: "switch-renderer-at"; index: number | "$" }
+  | { type: "switch-previewer"; amount: number; cycle?: boolean }
+  | { type: "switch-previewer-at"; index: number | "$" }
   | { type: "action-invoke"; name: string }
   | { type: "list-component-execute"; command: string }
   | { type: "preview-component-execute"; command: string }

denops/fall/main/event.ts

@@ -69,6 +69,15 @@ const isEventComplement = is.UnionOf([
     type: is.LiteralOf("switch-renderer-at"),
     index: is.UnionOf([is.Number, is.LiteralOf("$")]),
   }),
+  is.ObjectOf({
+    type: is.LiteralOf("switch-previewer"),
+    amount: is.Number,
+    cycle: as.Optional(is.Boolean),
+  }),
+  is.ObjectOf({
+    type: is.LiteralOf("switch-previewer-at"),
+    index: is.UnionOf([is.Number, is.LiteralOf("$")]),
+  }),
   // Action
   is.ObjectOf({
     type: is.LiteralOf("action-invoke"),

denops/fall/picker.ts

@@ -110,8 +110,7 @@ export class Picker<T extends Detail> implements AsyncDisposable {
       ),
     );
     this.#previewProcessor = this.#stack.use(
-      // TODO: Support multiple previewers
-      new PreviewProcessor(params.previewers?.at(0)),
+      new PreviewProcessor(params.previewers ?? []),
     );
   }
 
@@ -426,6 +425,29 @@ export class Picker<T extends Detail> implements AsyncDisposable {
           items: this.#matchProcessor.items,
         });
         break;
+      case "switch-previewer": {
+        if (!this.#previewProcessor) break;
+        let index = this.#previewProcessor.previewerIndex + event.amount;
+        if (event.cycle) {
+          if (index < 0) {
+            index = this.#previewProcessor.previewerCount - 1;
+          } else if (index >= this.#previewProcessor.previewerCount) {
+            index = 0;
+          }
+        }
+        this.#previewProcessor.previewerIndex = index;
+        this.#previewProcessor.start(denops, {
+          item: this.#matchProcessor.items[this.#visualizeProcessor.cursor],
+        });
+        break;
+      }
+      case "switch-previewer-at":
+        if (!this.#previewProcessor) break;
+        this.#previewProcessor.previewerIndex = event.index;
+        this.#previewProcessor.start(denops, {
+          item: this.#matchProcessor.items[this.#visualizeProcessor.cursor],
+        });
+        break;
       case "action-invoke":
         accept(event.name);
         break;

denops/fall/processor/preview.ts

@@ -8,14 +8,36 @@ import type {
 import { dispatch } from "../event.ts";
 
 export class PreviewProcessor<T extends Detail> {
-  #previewer?: Previewer<T>;
+  #previewers: Previewer<T>[];
   #controller: AbortController = new AbortController();
   #processing?: Promise<void>;
   #reserved?: () => void;
   #item: PreviewItem | undefined = undefined;
+  #previewerIndex = 0;
 
-  constructor(previewer: Previewer<T> | undefined) {
-    this.#previewer = previewer;
+  constructor(previewers: Previewer<T>[]) {
+    this.#previewers = previewers;
+  }
+
+  get #previewer(): Previewer<T> | undefined {
+    return this.#previewers[this.#previewerIndex];
+  }
+
+  get previewerCount(): number {
+    return this.#previewers.length;
+  }
+
+  get previewerIndex(): number {
+    return this.#previewerIndex;
+  }
+
+  set previewerIndex(index: number | "$") {
+    if (index === "$" || index >= this.#previewers.length) {
+      index = this.#previewers.length - 1;
+    } else if (index < 0) {
+      index = 0;
+    }
+    this.#previewerIndex = index;
   }
 
   get item(): PreviewItem | undefined {

plugin/fall/mapping.vim

@@ -32,6 +32,10 @@ cnoremap <silent> <Plug>(fall-switch-renderer-first) <Cmd>call fall#internal#dis
 cnoremap <silent> <Plug>(fall-switch-renderer-last) <Cmd>call fall#internal#dispatch(#{type: 'switch-renderer-at', index: '$'})<CR>
 cnoremap <silent> <Plug>(fall-switch-renderer-prev) <Cmd>call fall#internal#dispatch(#{type: 'switch-renderer', amount: -1, cycle: v:true})<CR>
 cnoremap <silent> <Plug>(fall-switch-renderer-next) <Cmd>call fall#internal#dispatch(#{type: 'switch-renderer', amount: 1, cycle: v:true})<CR>
+cnoremap <silent> <Plug>(fall-switch-previewer-first) <Cmd>call fall#internal#dispatch(#{type: 'switch-previewer-at', index: 0})<CR>
+cnoremap <silent> <Plug>(fall-switch-previewer-last) <Cmd>call fall#internal#dispatch(#{type: 'switch-previewer-at', index: '$'})<CR>
+cnoremap <silent> <Plug>(fall-switch-previewer-prev) <Cmd>call fall#internal#dispatch(#{type: 'switch-previewer', amount: -1, cycle: v:true})<CR>
+cnoremap <silent> <Plug>(fall-switch-previewer-next) <Cmd>call fall#internal#dispatch(#{type: 'switch-previewer', amount: 1, cycle: v:true})<CR>
 
 " Preview
 cnoremap <silent> <Plug>(fall-preview-first) <Cmd>call fall#internal#dispatch(#{type: 'preview-component-execute', command: 'silent! normal! gg'})<CR>
@@ -82,6 +86,7 @@ if !get(g:, 'fall_disable_default_mapping')
     cnoremap <nowait> <F2> <Plug>(fall-switch-matcher-next)
     cnoremap <nowait> <F3> <Plug>(fall-switch-sorter-next)
     cnoremap <nowait> <F4> <Plug>(fall-switch-renderer-next)
+    cnoremap <nowait> <F5> <Plug>(fall-switch-previewer-next)
   endfunction
 
   augroup fall_mapping_plugin