Added Structure View Implementation

build.gradle

@@ -100,11 +100,12 @@ compileTestJava {
 }
 
 intellij {
-    version = ideaVersion
+    version = '2023.3'
+    type = 'IC'
     pluginName = 'eo-intellij'
     downloadSources = false
     updateSinceUntilBuild = false
-    plugins = ["com.intellij.java", "org.jetbrains.idea.maven"]
+    plugins = ["com.intellij.java", "org.jetbrains.idea.maven", "java"]
 }
 
 test {

src/main/java/org/eolang/jetbrains/psi/EoAttributeDeclaration.java

@@ -0,0 +1,52 @@
+// SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+// SPDX-License-Identifier: MIT
+
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+ * SPDX-License-Identifier: MIT
+ */
+package org.eolang.jetbrains.psi;
+
+import com.intellij.extapi.psi.ASTWrapperPsiElement;
+import com.intellij.lang.ASTNode;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiNameIdentifierOwner;
+import com.intellij.util.IncorrectOperationException;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * PSI element representing an EO attribute declaration (e.g. "> @foo").
+ * @since 1.0
+ */
+public class EoAttributeDeclaration extends ASTWrapperPsiElement
+        implements PsiNameIdentifierOwner {
+
+    public EoAttributeDeclaration(@NotNull final ASTNode node) {
+        super(node);
+    }
+
+    @Override
+    public @Nullable PsiElement getNameIdentifier() {
+        return findChildByClass(EoIdentifier.class);
+    }
+
+    @Override
+    public @Nullable String getName() {
+        final PsiElement id = getNameIdentifier();
+        return id != null ? id.getText() : null;
+    }
+
+    @Override
+    public PsiElement setName(@NotNull final String newName)
+            throws IncorrectOperationException {
+        final PsiElement id = getNameIdentifier();
+        if (id != null) {
+            final PsiElement newId = EoPsiElementFactory.createIdentifier(
+                    getProject(), newName
+            );
+            id.replace(newId);
+        }
+        return this;
+    }
+}

src/main/java/org/eolang/jetbrains/psi/EoIdentifier.java

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+// SPDX-License-Identifier: MIT
+
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+ * SPDX-License-Identifier: MIT
+ */
+package org.eolang.jetbrains.psi;
+
+import com.intellij.extapi.psi.ASTWrapperPsiElement;
+import com.intellij.lang.ASTNode;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * PSI element for EO identifier tokens.
+ * Represents any name token in EO code.
+ * @since 1.0
+ */
+public class EoIdentifier extends ASTWrapperPsiElement {
+
+    /** @param node AST node for identifier */
+    public EoIdentifier(@NotNull final ASTNode node) {
+        super(node);
+    }
+}

src/main/java/org/eolang/jetbrains/psi/EoObjectDeclaration.java

@@ -0,0 +1,52 @@
+// SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+// SPDX-License-Identifier: MIT
+
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+ * SPDX-License-Identifier: MIT
+ */
+package org.eolang.jetbrains.psi;
+
+import com.intellij.extapi.psi.ASTWrapperPsiElement;
+import com.intellij.lang.ASTNode;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiNameIdentifierOwner;
+import com.intellij.util.IncorrectOperationException;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * PSI element representing an EO object declaration (e.g. "[args] > name").
+ * @since 1.0
+ */
+public class EoObjectDeclaration extends ASTWrapperPsiElement
+        implements PsiNameIdentifierOwner {
+
+    public EoObjectDeclaration(@NotNull final ASTNode node) {
+        super(node);
+    }
+
+    @Override
+    public @Nullable PsiElement getNameIdentifier() {
+        return findChildByClass(EoIdentifier.class);
+    }
+
+    @Override
+    public @Nullable String getName() {
+        final PsiElement id = getNameIdentifier();
+        return id != null ? id.getText() : null;
+    }
+
+    @Override
+    public PsiElement setName(@NotNull final String newName)
+            throws IncorrectOperationException {
+        final PsiElement id = getNameIdentifier();
+        if (id != null) {
+            final PsiElement newId = EoPsiElementFactory.createIdentifier(
+                    getProject(), newName
+            );
+            id.replace(newId);
+        }
+        return this;
+    }
+}

src/main/java/org/eolang/jetbrains/psi/EoPsiElementFactory.java

@@ -0,0 +1,53 @@
+// SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+// SPDX-License-Identifier: MIT
+
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+ * SPDX-License-Identifier: MIT
+ */
+package org.eolang.jetbrains.psi;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.PsiFileFactory;
+import com.intellij.psi.util.PsiTreeUtil;
+import org.jetbrains.annotations.NotNull;
+import org.eolang.jetbrains.EoFileType;
+
+/**
+ * Factory class for creating EO PSI elements programmatically.
+ * @since 1.0
+ */
+public final class EoPsiElementFactory {
+
+    private EoPsiElementFactory() {
+        // utility class
+    }
+
+    /**
+     * Creates a new EO identifier PSI element with the given name.
+     * @param project the current IntelliJ project
+     * @param name the identifier name
+     * @return a PSI element representing the identifier
+     */
+    @NotNull
+    public static PsiElement createIdentifier(
+            @NotNull final Project project,
+            @NotNull final String name
+    ) {
+        final String text = String.format("[args] > %s", name);
+        final PsiFile file = PsiFileFactory
+                .getInstance(project)
+                .createFileFromText("_dummy_.eo", EoFileType.INSTANCE, text);
+        final EoObjectDeclaration decl = PsiTreeUtil
+                .findChildOfType(file, EoObjectDeclaration.class);
+        if (decl != null) {
+            final PsiElement id = decl.getNameIdentifier();
+            if (id != null) {
+                return id;
+            }
+        }
+        return file;
+    }
+}

src/main/java/org/eolang/jetbrains/structview/EoAttributeStructureViewElement.java

@@ -0,0 +1,47 @@
+// SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+// SPDX-License-Identifier: MIT
+
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+ * SPDX-License-Identifier: MIT
+ */
+
+package org.eolang.jetbrains.structview;
+
+import com.intellij.ide.structureView.impl.common.PsiTreeElementBase;
+import com.intellij.ide.structureView.StructureViewTreeElement;
+import org.eolang.jetbrains.psi.EoAttributeDeclaration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Objects;
+
+/**
+ * Structure view element for EO attribute declarations (leaf nodes).
+ * @since 1.0
+ */
+public final class EoAttributeStructureViewElement
+        extends PsiTreeElementBase<EoAttributeDeclaration> {
+
+    /**
+     * @param attribute the EO attribute PSI element
+     */
+    public EoAttributeStructureViewElement(
+            @NotNull final EoAttributeDeclaration attribute
+    ) {
+        super(attribute);
+    }
+
+    @Override
+    public @NotNull Collection<StructureViewTreeElement> getChildrenBase() {
+        // Leaf nodes: no children
+        return Collections.emptyList();
+    }
+
+    @Override
+    public @Nullable String getPresentableText() {
+        return Objects.requireNonNull(getElement()).getName();
+    }
+}

src/main/java/org/eolang/jetbrains/structview/EoObjectStructureViewElement.java

@@ -0,0 +1,53 @@
+// SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+// SPDX-License-Identifier: MIT
+
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+ * SPDX-License-Identifier: MIT
+ */
+package org.eolang.jetbrains.structview;
+
+import com.intellij.ide.structureView.impl.common.PsiTreeElementBase;
+import com.intellij.ide.structureView.StructureViewTreeElement;
+import com.intellij.psi.util.PsiTreeUtil;
+import org.eolang.jetbrains.psi.EoObjectDeclaration;
+import org.eolang.jetbrains.psi.EoAttributeDeclaration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Structure view element for EO object declarations:
+ * object -> attribute declarations.
+ * @since 1.0
+ */
+public final class EoObjectStructureViewElement
+        extends PsiTreeElementBase<EoObjectDeclaration> {
+
+    /**
+     * @param obj the EO object declaration
+     */
+    public EoObjectStructureViewElement(@NotNull final EoObjectDeclaration obj) {
+        super(obj);
+    }
+
+    @Override
+    public @NotNull Collection<StructureViewTreeElement> getChildrenBase() {
+        final List<EoAttributeDeclaration> attrs = PsiTreeUtil
+                .getChildrenOfTypeAsList(getElement(), EoAttributeDeclaration.class);
+        final List<StructureViewTreeElement> children = new ArrayList<>(attrs.size());
+        for (final EoAttributeDeclaration attr : attrs) {
+            children.add(new EoAttributeStructureViewElement(attr));
+        }
+        return children;
+    }
+
+    @Override
+    public @Nullable String getPresentableText() {
+        return Objects.requireNonNull(getElement()).getName();
+    }
+}

src/main/java/org/eolang/jetbrains/structview/EoStructureViewElement.java

@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+// SPDX-License-Identifier: MIT
+
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2025 George Osenchakov
+ * SPDX-License-Identifier: MIT
+ */
+package org.eolang.jetbrains.structview;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import com.intellij.ide.structureView.impl.common.PsiTreeElementBase;
+import com.intellij.ide.structureView.StructureViewTreeElement;
+import com.intellij.psi.util.PsiTreeUtil;
+import org.jetbrains.annotations.NotNull;
+import org.eolang.jetbrains.psi.EoPsiFileRoot;
+import org.eolang.jetbrains.psi.EoObjectDeclaration;
+
+/**
+ * Structure view element for EO file root.
+ * Uses PSI tree search instead of custom getters.
+ * @since 1.0
+ */
+public final class EoStructureViewElement
+        extends PsiTreeElementBase<EoPsiFileRoot> {
+
+    /**
+     * @param file EO file root
+     */
+    public EoStructureViewElement(@NotNull final EoPsiFileRoot file) {
+        super(file);
+    }
+
+    @Override
+    public @NotNull Collection<StructureViewTreeElement> getChildrenBase() {
+        final EoPsiFileRoot file = getElement();
+        final List<StructureViewTreeElement> children = new ArrayList<>();
+        final List<EoObjectDeclaration> objects =
+                PsiTreeUtil.getChildrenOfTypeAsList(file, EoObjectDeclaration.class);
+        for (final EoObjectDeclaration obj : objects) {
+            children.add(new EoObjectStructureViewElement(obj));
+        }
+        return children;
+    }
+
+    @Override
+    public @NotNull String getPresentableText() {
+        return "";
+    }
+}