Implement -n command line feature

Author: bjfish

CHANGELOG.md

@@ -77,6 +77,7 @@ Compatibility:
 * Implemented `Enumerator::Chain`, `Enumerator#+`, and `Enumerable#chain` (#1859, #1858).
 * Implemented `Thread#backtrace_locations` and `Exception#backtrace_locations` (#1556).
 * Implemented `rb_module_new`, `rb_define_class_id`, `rb_define_module_id`, (#1876, @chrisseaton).
+* Implemented `-n` CLI option (#1532).
 
 Performance:
 

spec/tags/command_line/dash_n_tags.txt

@@ -1,4 +1,4 @@
-fails:The -n command line option runs the code in loop conditional on Kernel.gets()
-fails:The -n command line option only evaluates BEGIN blocks once
-fails:The -n command line option only evaluates END blocks once
-fails:The -n command line option allows summing over a whole file
+slow:The -n command line option runs the code in loop conditional on Kernel.gets()
+slow:The -n command line option only evaluates BEGIN blocks once
+slow:The -n command line option only evaluates END blocks once
+slow:The -n command line option allows summing over a whole file

src/launcher/java/org/truffleruby/launcher/CommandLineParser.java

@@ -305,7 +305,8 @@ private void processArgument() throws CommandLineException {
                     throw notImplemented("-l");
                 case 'n':
                     disallowedInRubyOpts(argument);
-                    throw notImplemented("-n");
+                    config.setOption(OptionsCatalog.GETS_LOOP, true);
+                    break;
                 case 'p':
                     disallowedInRubyOpts(argument);
                     throw notImplemented("-p");

src/main/java/org/truffleruby/core/kernel/KernelGetsNode.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2019 Oracle and/or its affiliates. All rights reserved. This
+ * code is released under a tri EPL/GPL/LGPL license. You can use it,
+ * redistribute it and/or modify it under the terms of the:
+ *
+ * Eclipse Public License version 2.0, or
+ * GNU General Public License version 2, or
+ * GNU Lesser General Public License version 2.1.
+ */
+package org.truffleruby.core.kernel;
+
+import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.frame.VirtualFrame;
+import org.truffleruby.language.RubyNode;
+import org.truffleruby.language.dispatch.CallDispatchHeadNode;
+
+public class KernelGetsNode extends RubyNode {
+
+    @Child private CallDispatchHeadNode callGetsNode;
+
+    @Override
+    public Object execute(VirtualFrame frame) {
+        if (callGetsNode == null) {
+            CompilerDirectives.transferToInterpreterAndInvalidate();
+            callGetsNode = insert(CallDispatchHeadNode.createPrivate());
+        }
+        return callGetsNode.dispatch(frame, coreLibrary().kernelModule, "gets", null, EMPTY_ARGUMENTS);
+    }
+
+}

src/main/java/org/truffleruby/options/Options.java

@@ -132,6 +132,8 @@ public class Options {
     public final boolean CEXTS_LOG_WARNINGS;
     /** --argv-globals=false */
     public final boolean ARGV_GLOBALS;
+    /** --gets-loop=false */
+    public final boolean GETS_LOOP;
     /** --ignore-lines-before-ruby-shebang=false */
     public final boolean IGNORE_LINES_BEFORE_RUBY_SHEBANG;
     /** --syntax-check=false */
@@ -321,6 +323,7 @@ public Options(Env env, OptionValues options) {
         CEXTS_LOG_LOAD = options.get(OptionsCatalog.CEXTS_LOG_LOAD_KEY);
         CEXTS_LOG_WARNINGS = options.get(OptionsCatalog.CEXTS_LOG_WARNINGS_KEY);
         ARGV_GLOBALS = options.get(OptionsCatalog.ARGV_GLOBALS_KEY);
+        GETS_LOOP = options.get(OptionsCatalog.GETS_LOOP_KEY);
         IGNORE_LINES_BEFORE_RUBY_SHEBANG = options.get(OptionsCatalog.IGNORE_LINES_BEFORE_RUBY_SHEBANG_KEY);
         SYNTAX_CHECK = options.get(OptionsCatalog.SYNTAX_CHECK_KEY);
         ARGV_GLOBAL_VALUES = options.get(OptionsCatalog.ARGV_GLOBAL_VALUES_KEY);
@@ -501,6 +504,8 @@ public Object fromDescriptor(OptionDescriptor descriptor) {
                 return CEXTS_LOG_WARNINGS;
             case "ruby.argv-globals":
                 return ARGV_GLOBALS;
+            case "ruby.gets-loop":
+                return GETS_LOOP;
             case "ruby.ignore-lines-before-ruby-shebang":
                 return IGNORE_LINES_BEFORE_RUBY_SHEBANG;
             case "ruby.syntax-check":

src/main/java/org/truffleruby/parser/TranslatorDriver.java

@@ -44,6 +44,7 @@
 import org.truffleruby.RubyContext;
 import org.truffleruby.aot.ParserCache;
 import org.truffleruby.core.LoadRequiredLibrariesNode;
+import org.truffleruby.core.kernel.KernelGetsNode;
 import org.truffleruby.language.DataNode;
 import org.truffleruby.language.LexicalScope;
 import org.truffleruby.language.RubyNode;
@@ -55,6 +56,7 @@
 import org.truffleruby.language.arguments.ReadPreArgumentNode;
 import org.truffleruby.language.arguments.RubyArguments;
 import org.truffleruby.language.control.RaiseException;
+import org.truffleruby.language.control.WhileNode;
 import org.truffleruby.language.exceptions.TopLevelRaiseHandler;
 import org.truffleruby.language.locals.WriteLocalVariableNode;
 import org.truffleruby.language.methods.Arity;
@@ -275,6 +277,10 @@ public RubyRootNode parse(RubySource rubySource, ParserContext parserContext, St
                     Arrays.asList(translator.initFlipFlopStates(sourceIndexLength), truffleNode));
         }
 
+        if (parserContext == ParserContext.TOP_LEVEL_FIRST && context.getOptions().GETS_LOOP) {
+            truffleNode = new WhileNode(new WhileNode.WhileRepeatingNode(context, new KernelGetsNode(), truffleNode));
+        }
+
         if (beginNode != null) {
             truffleNode = Translator.sequence(
                     sourceIndexLength,

src/options.yml

@@ -6,7 +6,6 @@ USER:
     WORKING_DIRECTORY: [[working-directory, -C], string, '', Interpreter will switch to this directory]
     DEBUG: [[debug, -d], boolean, false, 'Sets $DEBUG to this value']
     VERBOSITY: [[verbose, -v, -w, -W], enum/verbosity, false, 'Sets $VERBOSE to this value']
-
     SOURCE_ENCODING: [[source-encoding, -K], string, '', Source encoding]
     INTERNAL_ENCODING: [[internal-encoding, -E, -U], string, '', Internal encoding]
     EXTERNAL_ENCODING: [[external-encoding, -E], string, '', External encoding]
@@ -81,6 +80,7 @@ INTERNAL: # Options for debugging the TruffleRuby implementation
   EXPERIMENTAL:
     # Options corresponding to MRI options, which are only meaningful when using the TruffleRuby launcher
     ARGV_GLOBALS: [[argv-globals, -s], boolean, false, Parse options in script argv into global variables]
+    GETS_LOOP: [[gets-loop, -n], boolean, false, 'assume while gets(); ... end loop around your script']
     IGNORE_LINES_BEFORE_RUBY_SHEBANG: [[ignore-lines-before-ruby-shebang, -x], boolean, false, "strip off text before #!ruby line"]
     SYNTAX_CHECK: [[syntax-check, -c], boolean, false, Do not execute just check syntax]
 

src/shared/java/org/truffleruby/shared/options/OptionsCatalog.java

@@ -75,6 +75,7 @@ public class OptionsCatalog {
     public static final OptionKey<Boolean> CEXTS_LOG_LOAD_KEY = new OptionKey<>(false);
     public static final OptionKey<Boolean> CEXTS_LOG_WARNINGS_KEY = new OptionKey<>(false);
     public static final OptionKey<Boolean> ARGV_GLOBALS_KEY = new OptionKey<>(false);
+    public static final OptionKey<Boolean> GETS_LOOP_KEY = new OptionKey<>(false);
     public static final OptionKey<Boolean> IGNORE_LINES_BEFORE_RUBY_SHEBANG_KEY = new OptionKey<>(false);
     public static final OptionKey<Boolean> SYNTAX_CHECK_KEY = new OptionKey<>(false);
     public static final OptionKey<String[]> ARGV_GLOBAL_VALUES_KEY = new OptionKey<>(new String[]{}, StringArrayOptionType.INSTANCE);
@@ -527,6 +528,13 @@ public class OptionsCatalog {
             .stability(OptionStability.EXPERIMENTAL)
             .build();
 
+    public static final OptionDescriptor GETS_LOOP = OptionDescriptor
+            .newBuilder(GETS_LOOP_KEY, "ruby.gets-loop")
+            .help("assume while gets(); ... end loop around your script (configured by the -n Ruby option)")
+            .category(OptionCategory.INTERNAL)
+            .stability(OptionStability.EXPERIMENTAL)
+            .build();
+
     public static final OptionDescriptor IGNORE_LINES_BEFORE_RUBY_SHEBANG = OptionDescriptor
             .newBuilder(IGNORE_LINES_BEFORE_RUBY_SHEBANG_KEY, "ruby.ignore-lines-before-ruby-shebang")
             .help("strip off text before #!ruby line (configured by the -x Ruby option)")
@@ -1101,6 +1109,8 @@ public static OptionDescriptor fromName(String name) {
                 return CEXTS_LOG_WARNINGS;
             case "ruby.argv-globals":
                 return ARGV_GLOBALS;
+            case "ruby.gets-loop":
+                return GETS_LOOP;
             case "ruby.ignore-lines-before-ruby-shebang":
                 return IGNORE_LINES_BEFORE_RUBY_SHEBANG;
             case "ruby.syntax-check":
@@ -1295,6 +1305,7 @@ public static OptionDescriptor[] allDescriptors() {
             CEXTS_LOG_LOAD,
             CEXTS_LOG_WARNINGS,
             ARGV_GLOBALS,
+            GETS_LOOP,
             IGNORE_LINES_BEFORE_RUBY_SHEBANG,
             SYNTAX_CHECK,
             ARGV_GLOBAL_VALUES,