Extend the line magics fix to rpy2

Author: krassowski

packages/jupyterlab-lsp/src/transclusions/ipython-rpy2/overrides.spec.ts

@@ -76,6 +76,12 @@ describe('rpy2 IPython overrides', () => {
       expect(reverse).to.equal(line);
     });
 
+    it('does not substitute magic-like constructs', () => {
+      let line = 'print("%R -i x")';
+      let override = line_magics.override_for(line);
+      expect(override).to.equal(null);
+    });
+
     it('works with the long form arguments', () => {
       let line = '%R --input x';
       let override = line_magics.override_for(line);

packages/jupyterlab-lsp/src/transclusions/ipython-rpy2/overrides.ts

@@ -6,14 +6,18 @@ import {
   rpy2_reverse_pattern,
   rpy2_reverse_replacement
 } from './rpy2';
+import { LINE_MAGIC_PREFIX } from '../ipython/overrides';
 
 export let overrides: IScopedCodeOverride[] = [
   {
     // support up to 10 arguments
-    pattern: '%R' + rpy2_args_pattern(RPY2_MAX_ARGS) + '(.*)(\n)?',
-    replacement: (match, ...args) => {
+    pattern:
+      LINE_MAGIC_PREFIX + '%R' + rpy2_args_pattern(RPY2_MAX_ARGS) + '(.*)(\n)?',
+    replacement: (match, prefix, ...args) => {
       let r = parse_r_args(args, -4);
-      return `${r.outputs}rpy2.ipython.rmagic.RMagics.R("${r.content}", "${r.others}"${r.inputs})`;
+      // note: only supports assignment or -o/--output, not both
+      // TODO assignment like in x = %R 1 should be distinguished from -o
+      return `${prefix}${r.outputs}rpy2.ipython.rmagic.RMagics.R("${r.content}", "${r.others}"${r.inputs})`;
     },
     scope: 'line',
     reverse: {

packages/jupyterlab-lsp/src/transclusions/ipython/overrides.ts

@@ -36,6 +36,9 @@ function empty_or_escaped(x: string) {
  * This will not always work: e.g.:
  *    x['a = !ls'] = !ls
  * is perfectly valid IPython, but regular expressions cannot help here.
+ *
+ * Look behind could be used to avoid capturing the group,
+ * but at the time of writing support is only at 77%.
  */
 export const LINE_MAGIC_PREFIX = '^(\\s*|\\s*\\S+\\s*=\\s*)';