Add prototype

Author: EXL

util/Highlighter.java

@@ -0,0 +1,110 @@
+// Highlighter.java, no comments, no checks.
+// $ javac Highlighter.java
+// $ jar -cvfe highlighter.jar Highlighter *.class
+// $ cat hello.py | java -jar highlighter.jar rouge python
+import org.graalvm.polyglot.Context;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+
+import java.util.Scanner;
+
+public class Highlighter {
+ private abstract class Highlight {
+ protected final Context polyglot =
+ Context.newBuilder("js", "python", "ruby").allowAllAccess(true).allowIO(true)
+ .build();
+
+ protected abstract String language();
+ protected abstract String renderHtml(String language, String rawCode);
+
+ protected String execute(String sourceCode) {
+ try {
+ return polyglot.eval(language(), sourceCode).asString();
+ } catch (RuntimeException re) { re.printStackTrace(); }
+ return sourceCode;
+ }
+
+ protected void importValue(String name, String value) {
+ try {
+ polyglot.getBindings(language()).putMember(name, value);
+ } catch (RuntimeException re) { re.printStackTrace(); }
+ }
+ }
+
+ private class Hjs extends Highlight {
+ @Override
+ protected String language() { return "js"; }
+
+ @Override
+ public String renderHtml(String language, String rawCode) {
+ importValue("source", rawCode);
+
+ String hjs = "";
+ try {
+ hjs = new Scanner(new File("highlight.min.js")).useDelimiter("\\A").next();
+ } catch (FileNotFoundException fnfe) { fnfe.printStackTrace(); }
+
+ final String renderLanguageSnippet =
+ hjs + "\n" +
+ "hljs.highlight('" + language + "', String(source)).value";
+ return execute(renderLanguageSnippet);
+ }
+ }
+
+ private class Rouge extends Highlight {
+ @Override
+ protected String language() { return "ruby"; }
+
+ @Override
+ public String renderHtml(String language, String rawCode) {
+ importValue("$source", rawCode);
+ final String renderLanguageSnippet =
+ "require 'rouge'" + "\n" +
+
+ "formatter = Rouge::Formatters::HTML.new" + "\n" +
+ "lexer = Rouge::Lexer::find('" + language + "')" + "\n" +
+ "formatter.format(lexer.lex($source.to_str))";
+ return execute(renderLanguageSnippet);
+ }
+ }
+
+ private class Pygments extends Highlight {
+ @Override
+ protected String language() { return "python"; }
+
+ @Override
+ public String renderHtml(String language, String rawCode) {
+ importValue("source", rawCode);
+ final String renderLanguageSnippet =
+ "import site" + "\n" +
+ "from pygments import highlight" + "\n" +
+ "from pygments.lexers import get_lexer_by_name" + "\n" +
+ "from pygments.formatters import HtmlFormatter" + "\n" +
+
+ "formatter = HtmlFormatter(nowrap=True)" + "\n" +
+ "lexer = get_lexer_by_name('" + language + "')" + "\n" +
+ "highlight(source, lexer, formatter)";
+ return execute(renderLanguageSnippet);
+ }
+ }
+
+ public String highlight(String library, String language, String code) {
+ switch (library) {
+ default:
+ case "hjs": return new Hjs().renderHtml(language, code);
+ case "rouge": return new Rouge().renderHtml(language, code);
+ case "pygments": return new Pygments().renderHtml(language, code);
+ }
+ }
+
+ public static void main(String[] args) {
+ Scanner scanner = new Scanner(System.in).useDelimiter("\\A");
+ if (scanner.hasNext()) {
+ String code = scanner.next();
+ if (!code.isEmpty()) {
+ System.out.println(new Highlighter().highlight(args[0], args[1], code));
+ }
+ }
+ }
+}