Adding JSGLR1 placeholder inference for code completion

core/jsglr.common/src/main/java/mb/jsglr/common/JsglrParseInput.java

@@ -6,18 +6,53 @@
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.io.Serializable;
+import java.util.Objects;
+
+/**
+ * JSGLR parser input.
+ */
+public final class JsglrParseInput implements Serializable {
 
-public class JsglrParseInput implements Serializable {
     public final Text text;
     public final String startSymbol;
     public final @Nullable ResourceKey fileHint;
     public final @Nullable ResourcePath rootDirectoryHint;
+    public final boolean codeCompletionMode;
+    public final int cursorOffset;
 
-    public JsglrParseInput(Text text, String startSymbol, @Nullable ResourceKey fileHint, @Nullable ResourcePath rootDirectoryHint) {
+    /**
+     * Initializes a new instance of the {@link JsglrParseInput} class.
+     *
+     * @param text the text to be parsed
+     * @param startSymbol the start symbol of the grammar
+     * @param fileHint a hint of the file being parsed; or {@code null} when not specified
+     * @param rootDirectoryHint a hint of the project root directory; or {@code null} when not specified
+     * @param codeCompletionMode whether to parse in completion mode
+     * @param cursorOffset the zero-based cursor offset in the text
+     */
+    public JsglrParseInput(
+        Text text,
+        String startSymbol,
+        @Nullable ResourceKey fileHint,
+        @Nullable ResourcePath rootDirectoryHint,
+        boolean codeCompletionMode,
+        int cursorOffset
+    ) {
         this.text = text;
         this.startSymbol = startSymbol;
         this.fileHint = fileHint;
         this.rootDirectoryHint = rootDirectoryHint;
+        this.codeCompletionMode = codeCompletionMode;
+        this.cursorOffset = cursorOffset;
+    }
+
+    public JsglrParseInput(
+        Text text,
+        String startSymbol,
+        @Nullable ResourceKey fileHint,
+        @Nullable ResourcePath rootDirectoryHint
+    ) {
+        this(text, startSymbol, fileHint, rootDirectoryHint, false, 0);
     }
 
     public JsglrParseInput(Text text, String startSymbol, @Nullable ResourceKey fileHint) {
@@ -44,18 +79,23 @@ public JsglrParseInput(String text, String startSymbol) {
         if(this == o) return true;
         if(o == null || getClass() != o.getClass()) return false;
         final JsglrParseInput that = (JsglrParseInput)o;
-        if(!text.equals(that.text)) return false;
-        if(!startSymbol.equals(that.startSymbol)) return false;
-        if(fileHint != null ? !fileHint.equals(that.fileHint) : that.fileHint != null) return false;
-        return rootDirectoryHint != null ? rootDirectoryHint.equals(that.rootDirectoryHint) : that.rootDirectoryHint == null;
+        return this.text.equals(that.text)
+            && this.startSymbol.equals(that.startSymbol)
+            && Objects.equals(this.fileHint, that.fileHint)
+            && Objects.equals(this.rootDirectoryHint, that.rootDirectoryHint)
+            && this.codeCompletionMode == that.codeCompletionMode
+            && this.cursorOffset == that.cursorOffset;
     }
 
     @Override public int hashCode() {
-        int result = text.hashCode();
-        result = 31 * result + startSymbol.hashCode();
-        result = 31 * result + (fileHint != null ? fileHint.hashCode() : 0);
-        result = 31 * result + (rootDirectoryHint != null ? rootDirectoryHint.hashCode() : 0);
-        return result;
+        return Objects.hash(
+            text,
+            startSymbol,
+            fileHint,
+            rootDirectoryHint,
+            codeCompletionMode,
+            cursorOffset
+        );
     }
 
     @Override public String toString() {
@@ -64,6 +104,8 @@ public JsglrParseInput(String text, String startSymbol) {
             ", startSymbol='" + startSymbol + '\'' +
             ", fileHint=" + fileHint +
             ", rootDirectoryHint=" + rootDirectoryHint +
+            ", codeCompletionMode=" + codeCompletionMode +
+            ", cursorOffset=" + cursorOffset +
             '}';
     }
 }

core/jsglr.pie/src/main/java/mb/jsglr/pie/JsglrParseTaskDef.java

@@ -89,7 +89,9 @@ protected abstract Result<JsglrParseOutput, JsglrParseException> parse(
         Text text,
         @Nullable String startSymbol,
         @Nullable ResourceKey fileHint,
-        @Nullable ResourcePath rootDirectoryHint
+        @Nullable ResourcePath rootDirectoryHint,
+        boolean codeCompletionMode,
+        int cursorOffset
     ) throws IOException, InterruptedException;
 
 
@@ -98,8 +100,10 @@ public Result<JsglrParseOutput, JsglrParseException> exec(ExecContext context, J
         final @Nullable String startSymbol = input.startSymbol().orElse(null);
         final @Nullable ResourceKey fileHint = input.fileHint().getOr(null);
         final @Nullable ResourcePath rootDirectoryHint = input.rootDirectoryHint().orElse(null);
+        final boolean codeCompletionMode = input.codeCompletionMode();
+        final int cursorOffset = input.cursorOffset();
         try {
-            return parse(context, context.require(input.textSupplier()), startSymbol, fileHint, rootDirectoryHint);
+            return parse(context, context.require(input.textSupplier()), startSymbol, fileHint, rootDirectoryHint, codeCompletionMode, cursorOffset);
         } catch(UncheckedIOException e) {
             return Result.ofErr(JsglrParseException.readStringFail(e.getCause(), startSymbol, fileHint, rootDirectoryHint));
         }

core/jsglr.pie/src/main/java/mb/jsglr/pie/JsglrParseTaskInput.java

@@ -119,4 +119,8 @@ static Builder builder(JsglrParseTaskDef parse) {
     }
 
     Optional<ResourcePath> rootDirectoryHint();
+
+    @Value.Default default boolean codeCompletionMode() { return false; }
+
+    @Value.Default default int cursorOffset() { return Integer.MAX_VALUE; }
 }

core/jsglr1.common/src/main/java/mb/jsglr1/common/JSGLR1Parser.java

@@ -47,6 +47,7 @@ public JSGLR1Parser(JSGLR1ParseTable parseTable, ITermFactory termFactory) {
 
     public JsglrParseOutput parse(JsglrParseInput input) throws JsglrParseException, InterruptedException {
         try {
+            parser.setCompletionParse(input.codeCompletionMode, input.cursorOffset);
             final SGLRParseResult result = parser.parse(input.text.toString(), input.fileHint != null ? input.fileHint.toString() : null, input.startSymbol);
             if(result.output == null) {
                 throw new RuntimeException("BUG: parser returned null output even though parsing did not fail");

core/spoofax.compiler.spoofax2/src/main/java/mb/spoofax/compiler/spoofax2/language/Spoofax2ParserLanguageCompiler.java

@@ -33,7 +33,9 @@ public class Spoofax2ParserLanguageCompiler implements TaskDef<Spoofax2ParserLan
     public ListView<String> getCopyResources(Input input) {
         return ListView.of(
             input.parseTableAtermFileRelativePath(),
-            input.parseTablePersistedFileRelativePath()
+            input.parseTablePersistedFileRelativePath(),
+            input.completionParseTableAtermFileRelativePath(),
+            input.completionParseTablePersistedFileRelativePath()
         );
     }
 
@@ -61,10 +63,28 @@ class Builder extends Spoofax2ParserLanguageCompilerData.Input.Builder {}
             return "target/metaborg/table.bin";
         }
 
+        /**
+         * @return path to the completion parse table aterm file to copy, relative to the Spoofax 2 language specification project
+         * directory.
+         */
+        @Value.Default default String completionParseTableAtermFileRelativePath() {
+            return "target/metaborg/sdf-completions.tbl";
+        }
+
+        /**
+         * @return path to the completion parse table persisted file to copy, relative to the Spoofax 2 language specification
+         * project directory.
+         */
+        @Value.Default default String completionParseTablePersistedFileRelativePath() {
+            return "target/metaborg/table-completions.bin";
+        }
+
 
         default void syncTo(ParserLanguageCompiler.Input.Builder builder) {
             builder.parseTableAtermFileRelativePath(parseTableAtermFileRelativePath());
             builder.parseTablePersistedFileRelativePath(parseTablePersistedFileRelativePath());
+            builder.completionParseTableAtermFileRelativePath(completionParseTableAtermFileRelativePath());
+            builder.completionParseTablePersistedFileRelativePath(completionParseTablePersistedFileRelativePath());
         }
     }
 }

core/spoofax.compiler/src/main/java/mb/spoofax/compiler/adapter/AdapterProjectCompiler.java

@@ -449,6 +449,7 @@ class Builder extends AdapterProjectCompilerData.Input.Builder {}
             });
             codeCompletion().ifPresent((i) -> {
                 taskDefs.add(i.codeCompletionTaskDef(), i.baseCodeCompletionTaskDef());
+                taskDefs.add(i.astWithPlaceholdersTaskDef(), i.baseAstWithPlaceholdersTaskDef());
                 taskDefs.add(i.statixSpecTaskDef(), i.baseStatixSpecTaskDef());
             });
             referenceResolution().ifPresent((i) -> {

core/spoofax.compiler/src/main/java/mb/spoofax/compiler/adapter/CodeCompletionAdapterCompiler.java

@@ -24,6 +24,7 @@
 @Value.Enclosing
 public class CodeCompletionAdapterCompiler {
     private final TemplateWriter codeCompletionTaskDefTemplate;
+    private final TemplateWriter astWithPlaceholdersTaskDefTemplate;
     private final TemplateWriter statixSpecTaskDefTemplate;
 
     /**
@@ -34,13 +35,15 @@ public class CodeCompletionAdapterCompiler {
     @Inject public CodeCompletionAdapterCompiler(TemplateCompiler templateCompiler) {
         templateCompiler = templateCompiler.loadingFromClass(getClass());
         this.codeCompletionTaskDefTemplate = templateCompiler.getOrCompileToWriter("code_completion/CodeCompletionTaskDef.java.mustache");
+        this.astWithPlaceholdersTaskDefTemplate = templateCompiler.getOrCompileToWriter("code_completion/AstWithPlaceholdersTaskDef.java.mustache");
         this.statixSpecTaskDefTemplate = templateCompiler.getOrCompileToWriter("code_completion/StatixSpecTaskDef.java.mustache");
     }
 
     public None compile(ExecContext context, Input input) throws IOException {
         if(input.classKind().isManual()) return None.instance; // Nothing to generate: return.
         final ResourcePath generatedJavaSourcesDirectory = input.generatedJavaSourcesDirectory();
         codeCompletionTaskDefTemplate.write(context, input.baseCodeCompletionTaskDef().file(generatedJavaSourcesDirectory), input);
+        astWithPlaceholdersTaskDefTemplate.write(context, input.baseAstWithPlaceholdersTaskDef().file(generatedJavaSourcesDirectory), input);
         statixSpecTaskDefTemplate.write(context, input.baseStatixSpecTaskDef().file(generatedJavaSourcesDirectory), input);
         return None.instance;
     }
@@ -84,6 +87,18 @@ default TypeInfo codeCompletionTaskDef() {
             return extendCompleteTaskDef().orElseGet(this::baseCodeCompletionTaskDef);
         }
 
+        // AST-with-placeholders task definition
+
+        @Value.Default default TypeInfo baseAstWithPlaceholdersTaskDef() {
+            return TypeInfo.of(adapterProject().taskPackageId(), shared().defaultClassPrefix() + "AstWithPlaceholdersTaskDef");
+        }
+
+        Optional<TypeInfo> extendAstWithPlaceholdersTaskDef();
+
+        default TypeInfo astWithPlaceholdersTaskDef() {
+            return extendAstWithPlaceholdersTaskDef().orElseGet(this::baseAstWithPlaceholdersTaskDef);
+        }
+
         // Statix Spec task definition
 
         @Value.Default default TypeInfo baseStatixSpecTaskDef() {
@@ -125,6 +140,7 @@ default ListView<ResourcePath> javaSourceFiles() {
             final ResourcePath generatedJavaSourcesDirectory = generatedJavaSourcesDirectory();
             return ListView.of(
                 baseCodeCompletionTaskDef().file(generatedJavaSourcesDirectory),
+                baseAstWithPlaceholdersTaskDef().file(generatedJavaSourcesDirectory),
                 baseStatixSpecTaskDef().file(generatedJavaSourcesDirectory)
             );
         }

core/spoofax.compiler/src/main/java/mb/spoofax/compiler/language/ParserLanguageCompiler.java

@@ -22,12 +22,14 @@ public class ParserLanguageCompiler {
     private final TemplateWriter tableTemplate;
     private final TemplateWriter parserTemplate;
     private final TemplateWriter factoryTemplate;
+    private final TemplateWriter completionFactoryTemplate;
 
     @Inject public ParserLanguageCompiler(TemplateCompiler templateCompiler) {
         templateCompiler = templateCompiler.loadingFromClass(getClass());
         this.tableTemplate = templateCompiler.getOrCompileToWriter("parser/ParseTable.java.mustache");
         this.parserTemplate = templateCompiler.getOrCompileToWriter("parser/Parser.java.mustache");
         this.factoryTemplate = templateCompiler.getOrCompileToWriter("parser/ParserFactory.java.mustache");
+        this.completionFactoryTemplate = templateCompiler.getOrCompileToWriter("parser/CompletionParserFactory.java.mustache");
     }
 
 
@@ -37,6 +39,7 @@ public None compile(ExecContext context, Input input) throws IOException {
         tableTemplate.write(context, input.baseParseTable().file(generatedJavaSourcesDirectory), input);
         parserTemplate.write(context, input.baseParser().file(generatedJavaSourcesDirectory), input);
         factoryTemplate.write(context, input.baseParserFactory().file(generatedJavaSourcesDirectory), input);
+        completionFactoryTemplate.write(context, input.baseCompletionParserFactory().file(generatedJavaSourcesDirectory), input);
         return None.instance;
     }
 
@@ -74,6 +77,16 @@ class Builder extends ParserLanguageCompilerData.Input.Builder {}
          */
         String parseTablePersistedFileRelativePath();
 
+        /**
+         * @return path to the completion parse table aterm file to load, relative to the classloader resources.
+         */
+        String completionParseTableAtermFileRelativePath();
+
+        /**
+         * @return path to the completion parse table persisted file to load, relative to the classloader resources.
+         */
+        String completionParseTablePersistedFileRelativePath();
+
         @Value.Default default ParserVariant variant() { return ParserVariant.jsglr1(); }
 
 
@@ -126,6 +139,30 @@ default TypeInfo parserFactory() {
             return extendParserFactory().orElseGet(this::baseParserFactory);
         }
 
+        // Completion Parser
+
+        @Value.Default default TypeInfo baseCompletionParser() {
+            return TypeInfo.of(languageProject().packageId(), shared().defaultClassPrefix() + "Parser");
+        }
+
+        Optional<TypeInfo> extendCompletionParser();
+
+        default TypeInfo completionParser() {
+            return extendCompletionParser().orElseGet(this::baseCompletionParser);
+        }
+
+        // Completion Parser factory
+
+        @Value.Default default TypeInfo baseCompletionParserFactory() {
+            return TypeInfo.of(languageProject().packageId(), shared().defaultClassPrefix() + "CompletionParserFactory");
+        }
+
+        Optional<TypeInfo> extendCompletionParserFactory();
+
+        default TypeInfo completionParserFactory() {
+            return extendCompletionParserFactory().orElseGet(this::baseCompletionParserFactory);
+        }
+
 
         /// Mustache template helpers
 

core/spoofax.compiler/src/main/resources/mb/spoofax/compiler/adapter/adapter_project/Instance.java.mustache

@@ -102,7 +102,12 @@ public class {{baseInstance.id}} implements LanguageInstance
 
     @Override public Task<Option<Styling>> createStyleTask(ResourceKey file, @Nullable ResourcePath rootDirectoryHint) {
 {{#parseInjection}}
-        return {{styleInjection.name}}.createTask({{this.name}}.inputBuilder().withFile(file).rootDirectoryHint(Optional.ofNullable(rootDirectoryHint)).buildRecoverableTokensSupplier().map(TokensResultToOkFunction.instance));
+        return {{styleInjection.name}}.createTask({{this.name}}.inputBuilder()
+            .withFile(file)
+            .rootDirectoryHint(Optional.ofNullable(rootDirectoryHint))
+            .buildRecoverableTokensSupplier()
+            .map(TokensResultToOkFunction.instance)
+        );
 {{/parseInjection}}
 {{^parseInjection}}
         return {{styleInjection.name}}.createTask((ctx) -> mb.pie.api.None.instance);

core/spoofax.compiler/src/main/resources/mb/spoofax/compiler/adapter/adapter_project/Module.java.mustache

@@ -78,6 +78,16 @@ public class {{baseModule.id}} {
         return parserFactory.create();
     }
 
+    @Provides @{{scope.id}} @Named("completion")
+    static {{this.languageProjectInput.completionParserFactory.qualifiedId}} provideCompletionParserFactory(@{{qualifier.id}}("definition-directory") HierarchicalResource definitionDir) {
+        return new {{this.languageProjectInput.completionParserFactory.qualifiedId}}(definitionDir);
+    }
+
+    @Provides @Named("completion") /* Unscoped: parser has state, so create a new parser every call. */
+    static {{this.languageProjectInput.completionParser.qualifiedId}} provideCompletionParser(@Named("completion") {{this.languageProjectInput.completionParserFactory.qualifiedId}} parserFactory) {
+        return parserFactory.create();
+    }
+
     @Provides @{{scope.id}}
     static ITermFactory provideTermFactory() {
         return new org.spoofax.jsglr.client.imploder.ImploderOriginTermFactory(new TermFactory());

core/spoofax.compiler/src/main/resources/mb/spoofax/compiler/adapter/code_completion/AstWithPlaceholdersTaskDef.java.mustache

@@ -0,0 +1,27 @@
+package {{baseAstWithPlaceholdersTaskDef.packageId}};
+
+import mb.log.api.LoggerFactory;
+import mb.statix.codecompletion.pie.AstWithPlaceholdersTaskDef;
+
+import javax.inject.Inject;
+
+@{{adapterProject.scope.qualifiedId}}
+public class {{baseAstWithPlaceholdersTaskDef.id}} extends AstWithPlaceholdersTaskDef {
+
+    @Inject
+    public {{baseAstWithPlaceholdersTaskDef.id}}(
+        {{strategoRuntimeInput.getStrategoRuntimeProviderTaskDef.qualifiedId}} getStrategoRuntimeProviderTask,
+        LoggerFactory loggerFactory
+    ) {
+        super(
+            getStrategoRuntimeProviderTask,
+            loggerFactory
+        );
+    }
+
+    @Override
+    public String getId() {
+        return "{{baseAstWithPlaceholdersTaskDef.id}}";
+    }
+
+}

core/spoofax.compiler/src/main/resources/mb/spoofax/compiler/adapter/code_completion/CodeCompletionTaskDef.java.mustache

@@ -6,7 +6,7 @@ import mb.log.api.LoggerFactory;
 import mb.nabl2.terms.stratego.StrategoTerms;
 import mb.pie.api.ExecContext;
 import mb.pie.api.stamp.resource.ResourceStampers;
-import mb.statix.codecompletion.pie.CodeCompletionEventHandlerBase;
+import mb.statix.codecompletion.pie.AstWithPlaceholdersTaskDef;
 import mb.statix.codecompletion.pie.CodeCompletionTaskDef;
 import mb.tego.strategies.runtime.TegoRuntime;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -22,6 +22,7 @@ public class {{baseCodeCompletionTaskDef.id}} extends CodeCompletionTaskDef {
     public {{baseCodeCompletionTaskDef.id}}(
         {{parserInput.parseTaskDef.qualifiedId}} parseTask,
         {{constraintAnalyzerInput.analyzeFileTaskDef.qualifiedId}} analyzeFileTask,
+        {{astWithPlaceholdersTaskDef.qualifiedId}} astWithPlaceholdersTaskDef,
         {{strategoRuntimeInput.getStrategoRuntimeProviderTaskDef.qualifiedId}} getStrategoRuntimeProviderTask,
         TegoRuntime tegoRuntime,
         {{statixSpecTaskDef.qualifiedId}} statixSpec,
@@ -32,6 +33,7 @@ public class {{baseCodeCompletionTaskDef.id}} extends CodeCompletionTaskDef {
         super(
             parseTask,
             analyzeFileTask,
+            astWithPlaceholdersTaskDef,
             getStrategoRuntimeProviderTask,
             tegoRuntime,
             statixSpec,