Tab/Shift-Tab indentTabStop/deindentTabStop

Author: fredsa

src/ide/views/tabs.ts

@@ -1,16 +1,143 @@
-import { indentLess, insertTab } from "@codemirror/commands";
 import { indentUnit } from "@codemirror/language";
-import { EditorState, Extension } from "@codemirror/state";
-import { keymap } from "@codemirror/view";
+import { EditorSelection, EditorState, Extension } from "@codemirror/state";
+import { EditorView, keymap } from "@codemirror/view";
+import { AsmTabStops, columnAt } from "../../common/tabdetect";
 import { tabStopsFacet } from "../settings";
 
+export const MAX_COLS = 300;
+
+export function tabStopsToColumns(asmTabStops: AsmTabStops, tabSize: number, useTabs?: boolean): number[] {
+  if (!useTabs) {
+    const asmCols = [asmTabStops.opcodes, asmTabStops.operands, asmTabStops.comments].filter((n): n is number => n > 0);
+    if (asmCols.length > 0) return asmCols;
+  }
+  const cols: number[] = [];
+  for (let col = tabSize; col < MAX_COLS; col += tabSize) {
+    cols.push(col);
+  }
+  return cols;
+}
+
+function nextTabStop(col: number, columns: number[]): number {
+  for (const stop of columns) {
+    if (stop > col) return stop;
+  }
+  return col;
+}
+
+function prevTabStop(col: number, columns: number[]): number {
+  for (let i = columns.length - 1; i >= 0; i--) {
+    if (columns[i] < col) return columns[i];
+  }
+  return 0;
+}
+
+function indentTabStop(view: EditorView): boolean {
+  const useTabs = view.state.facet(indentUnit) === '\t';
+  const asmTabStop = view.state.facet(tabStopsFacet);
+  const tabSize = view.state.facet(EditorState.tabSize);
+  const columns = tabStopsToColumns(asmTabStop, tabSize, useTabs);
+
+  // Indents lines for selected ranges.
+  if (view.state.selection.ranges.some(r => !r.empty)) {
+    const changes: { from: number; to: number; insert: string }[] = [];
+    const seen = new Set<number>();
+    for (const range of view.state.selection.ranges) {
+      const fromLine = view.state.doc.lineAt(range.from).number;
+      const toLine = view.state.doc.lineAt(range.to).number;
+      for (let ln = fromLine; ln <= toLine; ln++) {
+        if (seen.has(ln)) continue;
+        seen.add(ln);
+        const line = view.state.doc.line(ln);
+        let wsEnd = 0, wsCol = 0;
+        for (; wsEnd < line.text.length; wsEnd++) {
+          if (line.text[wsEnd] === '\t') wsCol = wsCol + tabSize - (wsCol % tabSize);
+          else if (line.text[wsEnd] === ' ') wsCol++;
+          else break;
+        }
+        if (useTabs) {
+          const insertAt = line.from + wsEnd;
+          changes.push({ from: insertAt, to: insertAt, insert: '\t' });
+        } else {
+          const targetCol = nextTabStop(wsCol, columns);
+          if (targetCol > wsCol) {
+            changes.push({ from: line.from, to: line.from + wsEnd, insert: ' '.repeat(targetCol) });
+          }
+        }
+      }
+    }
+    if (changes.length > 0) {
+      view.dispatch({ changes });
+    }
+    return true;
+  }
+
+  // Otherwise, inserts whitespace to next tab stop.
+  view.dispatch(view.state.changeByRange(range => {
+    const line = view.state.doc.lineAt(range.head);
+    const col = columnAt(line.text, range.head - line.from, tabSize);
+    const insert = useTabs ? '\t' : ' '.repeat(nextTabStop(col, columns) - col);
+    return {
+      changes: { from: range.head, insert },
+      range: EditorSelection.cursor(range.head + insert.length)
+    };
+  }));
+  return true;
+}
+
+function deindentTabStop(view: EditorView): boolean {
+  const useTabs = view.state.facet(indentUnit) === '\t';
+  const asmTabStop = view.state.facet(tabStopsFacet);
+  const tabSize = view.state.facet(EditorState.tabSize);
+  const columns = tabStopsToColumns(asmTabStop, tabSize, useTabs);
+
+  // Dedents lines for all ranges, regardless of selection.
+  const changes: { from: number; to: number; insert: string }[] = [];
+  const seen = new Set<number>();
+  for (const range of view.state.selection.ranges) {
+    const fromLine = view.state.doc.lineAt(range.from).number;
+    const toLine = view.state.doc.lineAt(range.to).number;
+    for (let ln = fromLine; ln <= toLine; ln++) {
+      if (seen.has(ln)) continue;
+      seen.add(ln);
+      const line = view.state.doc.line(ln);
+      let wsEnd = 0, wsCol = 0;
+      for (; wsEnd < line.text.length; wsEnd++) {
+        if (line.text[wsEnd] === '\t') wsCol = wsCol + tabSize - (wsCol % tabSize);
+        else if (line.text[wsEnd] === ' ') wsCol++;
+        else break;
+      }
+      if (wsCol === 0) continue;
+      const targetCol = prevTabStop(wsCol, columns);
+      // Walk forward to find the offset where we reach or pass targetCol.
+      let col = 0, prevCol = 0, off = 0;
+      for (; off < wsEnd && col < targetCol; off++) {
+        prevCol = col;
+        if (line.text[off] === '\t') col = col + tabSize - (col % tabSize);
+        else col++;
+      }
+      if (col > targetCol) {
+        // A tab overshot targetCol — replace it with spaces to land exactly on targetCol.
+        changes.push({ from: line.from + off - 1, to: line.from + wsEnd, insert: ' '.repeat(targetCol - prevCol) });
+      } else {
+        // Landed exactly on targetCol — just delete the rest.
+        changes.push({ from: line.from + off, to: line.from + wsEnd, insert: '' });
+      }
+    }
+  }
+  if (changes.length > 0) {
+    view.dispatch({ changes });
+  }
+  return true;
+}
+
 export function tabExtension(tabSize: number, tabsToSpaces: boolean, asmTabStops: AsmTabStops): Extension {
   return [
     EditorState.tabSize.of(tabSize),
     indentUnit.of(tabsToSpaces ? " ".repeat(tabSize) : "\t"),
     keymap.of([
-      { key: "Tab", run: insertTab },
-      { key: "Shift-Tab", run: indentLess }
+      { key: "Tab", run: indentTabStop },
+      { key: "Shift-Tab", run: deindentTabStop }
     ]),
     tabStopsFacet.of(asmTabStops),
   ];