Add initial scala support (#2737)

* Add initial scala support

* Fix scala 3 compiler flags

* Use semver instead

CONTRIBUTORS.md

@@ -101,3 +101,4 @@ From oldest to newest contributor, we would like to thank:
 - [Shivam Gupta](https://github.com/xgupta)
 - [Tamir Bahar](https://github.com/tmr232)
 - [Daniel Below](https://github.com/DanielBelow)
+- [Oleksandr Muliar](https://github.com/msdinit)

etc/config/scala.amazon.properties

@@ -0,0 +1,26 @@
+compilers=&scala
+compilerType=scala
+versionFlag=-version
+objdumper=/opt/compiler-explorer/jdk-16.0.1/bin/javap
+instructionSet=java
+defaultCompiler=scalac2136
+demangler=
+postProcess=
+options=
+supportsBinary=false
+needsMulti=false
+supportsExecute=false
+
+group.scala.compilers=scalac2136:scalac21214:scalac300
+group.scala.groupName=Scala
+group.scala.baseName=scalac
+group.scala.isSemVer=true
+compiler.scalac2136.exe=/opt/compiler-explorer/scala-2.13.6/bin/scalac
+compiler.scalac2136.semver=2.13.6
+compiler.scalac2136.java_home=/opt/compiler-explorer/jdk-16.0.1
+compiler.scalac21214.exe=/opt/compiler-explorer/scala-2.12.14/bin/scalac
+compiler.scalac21214.semver=2.12.14
+compiler.scalac21214.java_home=/opt/compiler-explorer/jdk-16.0.1
+compiler.scalac300.exe=/opt/compiler-explorer/scala3-3.0.0/bin/scalac
+compiler.scalac300.semver=3.0.0
+compiler.scalac300.java_home=/opt/compiler-explorer/jdk-16.0.1

etc/config/scala.defaults.properties

@@ -0,0 +1,18 @@
+# Default settings for Scala/JVM
+compilers=&scala
+compilerType=scala
+versionFlag=-version
+objdumper=javap
+instructionSet=java
+
+group.scala.compilers=scalacdefault
+compiler.scalacdefault.exe=/usr/bin/scalac
+compiler.scalacdefault.name=scalac default
+
+defaultCompiler=scalacdefault
+demangler=
+postProcess=
+options=
+supportsBinary=false
+needsMulti=false
+supportsExecute=false

examples/scala/default.scala

@@ -0,0 +1,5 @@
+// Type your code here, or load an example.
+object Square {
+    def square(num: Int): Int =
+        num * num
+}

lib/compilers/_all.js

@@ -59,6 +59,7 @@ export { PtxAssembler } from './ptxas';
 export { PythonCompiler } from './python';
 export { RustCompiler } from './rust';
 export { MrustcCompiler } from './mrustc';
+export { ScalaCompiler } from './scala';
 export { SdccCompiler } from './sdcc';
 export { SwiftCompiler } from './swift';
 export { TenDRACompiler } from './tendra';

lib/compilers/argument-parsers.js

@@ -185,6 +185,13 @@ export class KotlinParser extends BaseParser {
     }
 }
 
+export class ScalaParser extends BaseParser {
+    static async parse(compiler) {
+        await ScalaParser.getOptions(compiler, '-help');
+        return compiler;
+    }
+}
+
 export class VCParser extends BaseParser {
     static async parse(compiler) {
         await VCParser.getOptions(compiler, '/help');

lib/compilers/scala.js

@@ -0,0 +1,76 @@
+// Copyright (c) 2021, Compiler Explorer Authors
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+//     * Redistributions of source code must retain the above copyright notice,
+//       this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above copyright
+//       notice, this list of conditions and the following disclaimer in the
+//       documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+import { ScalaParser } from './argument-parsers';
+import { JavaCompiler } from './java';
+
+export class ScalaCompiler extends JavaCompiler {
+    static get key() {
+        return 'scala';
+    }
+
+    getDefaultExecOptions() {
+        const execOptions = super.getDefaultExecOptions();
+        const javaHome = this.compilerProps(`compiler.${this.compiler.id}.java_home`);
+        if (javaHome) {
+            execOptions.env.JAVA_HOME = javaHome;
+        }
+
+        return execOptions;
+    }
+
+    filterUserOptions(userOptions) {
+        // filter options without extra arguments
+        userOptions = userOptions.filter(option =>
+            option !== '-Xscript');
+
+        const oneArgForbiddenList = new Set([
+            // -d directory
+            // Destination for generated class files
+            '-d',
+        ]);
+
+        // filter options with one argument
+        return super.filterUserOptionsWithArg(userOptions, oneArgForbiddenList);
+    }
+
+    optionsForFilter(filters) {
+        // Forcibly enable javap
+        filters.binary = true;
+
+        const scala2Opts = [
+            '-Xlint:_',
+        ];
+
+        const scala3Opts = [
+            '-deprecation',
+        ];
+
+        return this.compiler.semver.startsWith('3') ? scala3Opts : scala2Opts;
+    }
+
+    getArgumentParser() {
+        return ScalaParser;
+    }
+}

lib/languages.js

@@ -130,6 +130,12 @@ export const languages = {
         extensions: ['.kt'],
         alias: [],
     },
+    scala: {
+        name: 'Scala',
+        monaco: 'scala',
+        extensions: ['.scala'],
+        alias: [],
+    },
     ocaml: {
         name: 'OCaml',
         monaco: 'ocaml',

webpack.config.esm.js

@@ -46,7 +46,7 @@ const staticPath = path.join(distPath, 'static');
 const webjackJsHack = '.v4.';
 const plugins = [
     new MonacoEditorWebpackPlugin({
-        languages: [ 'cpp', 'go', 'pascal', 'python', 'rust', 'swift', 'java', 'kotlin' ],
+        languages: [ 'cpp', 'go', 'pascal', 'python', 'rust', 'swift', 'java', 'kotlin', 'scala' ],
         filename: isDev ? '[name].worker.js' : `[name]${webjackJsHack}worker.[contenthash].js`,
     }),
     new CopyWebpackPlugin([