Provide a way to refresh a grammar or theme without restarting Eclipse

[cabintech]

It is wildly tedious to test incremental changes to grammars and themes loaded from files (e.g. not plugins). The TextMate preferences has no 'reload' option for grammar or theme files. So one approach is to delete the grammar/theme, then re-load it. But if you don't close and reopen the Preferences dialog that does not work (it is not enough to delete, "apply", and reload). Then close and reopen the generic editor to see the changes... but this works only for themes, grammars still do not update. For that you have to exist and restart Eclipse.

[Correction, with the latest release themes (very nicely) update live from the file system the next time the editor gets focus, but grammars do not.]

[sebthom]

FYI: For themes reload is implemented in the UI plugin like this:

tm4e/org.eclipse.tm4e.ui/src/main/java/org/eclipse/tm4e/ui/themes/Theme.java

Lines 150 to 183 in 58fb548

	private ITokenProvider getTokenProvider() {
	if (tokenProvider == null || isModified()) {
	try (InputStream in = getInputStream()) {
	final var path = getPath();
	final String extension = path.substring(path.lastIndexOf('.') + 1).trim().toLowerCase();
	tokenProvider = switch (extension) {
	case "css" -> new CSSTokenProvider(in);
	case "json" -> new TMThemeTokenProvider(ContentType.JSON, in);
	case "yaml", "yaml-tmtheme", "yml" -> new TMThemeTokenProvider(ContentType.YAML, in);
	case "plist", "tmtheme", "xml" -> new TMThemeTokenProvider(ContentType.XML, in);
	default -> throw new IllegalArgumentException("Unsupported file type: " + path);
	};
	} catch (final Exception ex) {
	TMUIPlugin.logError(ex);
	return null;
	}
	}
	return tokenProvider;
	}
	private long lastModified = -1;
	private long lastModifiedRecheck = -1;
	private boolean isModified() {
	final long now = System.currentTimeMillis();
	if (now > lastModifiedRecheck) {
	lastModifiedRecheck = now + 5_000;
	final long oldModified = lastModified;
	lastModified = getLastModified();
	return lastModified != oldModified;
	}
	return false;
	}