Step 80: selection and clipboard

PROGRESS.md

@@ -175,6 +175,7 @@ All 38 steps implemented and passing. Each step has a corresponding test (`step1
 - [x] Step 77: **IMPLEMENTED** — Custom CodeEditorWidget renderer: per-token coloring, cursor/selection/input handling, monospace grid, blinking cursor, visible whitespace toggle (3/3 tests pass)
 - [x] Step 78: **IMPLEMENTED** — Line numbers and gutter: fixed-width gutter with right-aligned line numbers, current line highlight, gutter click selects line (2/2 tests pass)
 - [x] Step 79: **IMPLEMENTED** — Auto-indent and smart editing: EditorMode integration, enter auto-indent, tab inserts spaces, auto-close brackets/quotes (3/3 tests pass)
+- [x] Step 80: **IMPLEMENTED** — Scroll/selection/clipboard: shift-extend selection, double/triple click selection, Ctrl+C/X/V clipboard, drag select (3/3 tests pass)
 
 ---
 
@@ -233,6 +234,7 @@ vcpkg's imgui 1.91.9 removed the `sdl2-binding` feature (only `sdl3-binding` exi
 **Step 77:** Compile and pass (3/3)
 **Step 78:** Compile and pass (2/2)
 **Step 79:** Compile and pass (3/3)
+**Step 80:** Compile and pass (3/3)
 
 ---
 
@@ -320,3 +322,4 @@ Sprint 4 in progress. Step 76 (LayoutManager) done. Next: Step 77 (custom code e
 | 2026-02-09 | Codex | Step 77: Custom code editor renderer (CodeEditorWidget). Per-token coloring, cursor/selection/input, blinking cursor, whitespace toggle. 3/3 tests pass. |
 | 2026-02-09 | Codex | Step 78: Line numbers and gutter. Gutter width auto-adjusts, current line highlight, gutter click selects line. 2/2 tests pass. |
 | 2026-02-09 | Codex | Step 79: Auto-indent and smart editing. EditorMode wired for newline indent, tab spacing, and bracket auto-close. 3/3 tests pass. |
+| 2026-02-09 | Codex | Step 80: Selection and clipboard operations (Ctrl+C/X/V, shift-extend, double/triple click). 3/3 tests pass. |

editor/CMakeLists.txt

@@ -335,6 +335,10 @@ add_executable(step79_test tests/step79_test.cpp)
 target_include_directories(step79_test PRIVATE src)
 target_link_libraries(step79_test PRIVATE imgui::imgui)
 
+add_executable(step80_test tests/step80_test.cpp)
+target_include_directories(step80_test PRIVATE src)
+target_link_libraries(step80_test PRIVATE imgui::imgui)
+
 find_package(SDL2 CONFIG REQUIRED)
 find_package(OpenGL REQUIRED)
 find_package(glad CONFIG REQUIRED)

editor/src/CodeEditorWidget.h

@@ -12,6 +12,7 @@
 #include <string>
 #include <vector>
 #include <algorithm>
+#include <cctype>
 
 struct CodeEditorOptions {
     bool showWhitespace = false;
@@ -96,7 +97,8 @@ public:
         if (hovered && ImGui::IsMouseClicked(ImGuiMouseButton_Left)) {
             ImGui::SetKeyboardFocusHere(-1);
             const ImVec2 mouse = ImGui::GetMousePos();
-            if (mouse.x < origin.x + gutterWidth) {
+            int clickCount = ImGui::GetIO().MouseClickedCount[0];
+            if (mouse.x < origin.x + gutterWidth || clickCount >= 3) {
                 int line = lineFromMouseY(mouse.y, gutterBase.y, lineHeight, lineCount);
                 int lineStart = lineStarts[line];
                 int lineEnd = (line + 1 < lineCount) ? lineStarts[line + 1] : (int)text.size();
@@ -104,9 +106,18 @@ public:
                 selStart_ = lineStart;
                 selEnd_ = lineEnd;
             } else {
-                cursor_ = positionFromMouse(mouse, textBase, lineStarts, text, charAdvance, lineHeight);
+                int pos = positionFromMouse(mouse, textBase, lineStarts, text, charAdvance, lineHeight);
-                selStart_ = cursor_;
+                if (ImGui::IsMouseDoubleClicked(ImGuiMouseButton_Left)) {
-                selEnd_ = cursor_;
+                    selectWordAt(text, pos);
+                } else if (ImGui::GetIO().KeyShift) {
+                    if (!hasSelection()) selStart_ = cursor_;
+                    cursor_ = pos;
+                    selEnd_ = cursor_;
+                } else {
+                    cursor_ = pos;
+                    selStart_ = cursor_;
+                    selEnd_ = cursor_;
+                }
             }
             selecting_ = true;
         }
@@ -399,20 +410,30 @@ private:
         io.InputQueueCharacters.resize(0);
 
         // Navigation
-        if (ImGui::IsKeyPressed(ImGuiKey_LeftArrow)) {
+        auto moveCursor = [&](int newPos) {
-            if (hasSelection()) {
+            newPos = std::max(0, std::min(newPos, (int)text.size()));
-                cursor_ = std::min(selStart_, selEnd_);
+            if (io.KeyShift) {
+                if (!hasSelection()) selStart_ = cursor_;
+                cursor_ = newPos;
+                selEnd_ = cursor_;
+            } else {
+                cursor_ = newPos;
                 selStart_ = selEnd_ = -1;
+            }
+        };
+
+        if (ImGui::IsKeyPressed(ImGuiKey_LeftArrow)) {
+            if (!io.KeyShift && hasSelection()) {
+                moveCursor(std::min(selStart_, selEnd_));
             } else if (cursor_ > 0) {
-                cursor_--;
+                moveCursor(cursor_ - 1);
             }
         }
         if (ImGui::IsKeyPressed(ImGuiKey_RightArrow)) {
-            if (hasSelection()) {
+            if (!io.KeyShift && hasSelection()) {
-                cursor_ = std::max(selStart_, selEnd_);
+                moveCursor(std::max(selStart_, selEnd_));
-                selStart_ = selEnd_ = -1;
             } else if (cursor_ < (int)text.size()) {
-                cursor_++;
+                moveCursor(cursor_ + 1);
             }
         }
         if (ImGui::IsKeyPressed(ImGuiKey_UpArrow)) {
@@ -422,7 +443,7 @@ private:
                 int prevStart = lineStarts[curLine - 1];
                 int prevEnd = (curLine < (int)lineStarts.size()) ? lineStarts[curLine] - 1 : (int)text.size();
                 int prevLen = std::max(0, prevEnd - prevStart);
-                cursor_ = prevStart + std::min(curCol, prevLen);
+                moveCursor(prevStart + std::min(curCol, prevLen));
             }
         }
         if (ImGui::IsKeyPressed(ImGuiKey_DownArrow)) {
@@ -432,7 +453,7 @@ private:
                 int nextStart = lineStarts[curLine + 1];
                 int nextEnd = (curLine + 2 < (int)lineStarts.size()) ? lineStarts[curLine + 2] - 1 : (int)text.size();
                 int nextLen = std::max(0, nextEnd - nextStart);
-                cursor_ = nextStart + std::min(curCol, nextLen);
+                moveCursor(nextStart + std::min(curCol, nextLen));
             }
         }
 
@@ -460,5 +481,43 @@ private:
             selEnd_ = (int)text.size();
             cursor_ = selEnd_;
         }
+
+        if ((io.KeyCtrl || io.KeySuper) && ImGui::IsKeyPressed(ImGuiKey_C)) {
+            if (hasSelection()) {
+                ImGui::SetClipboardText(getSelectionText(text).c_str());
+            }
+        }
+        if ((io.KeyCtrl || io.KeySuper) && ImGui::IsKeyPressed(ImGuiKey_X)) {
+            if (hasSelection()) {
+                ImGui::SetClipboardText(getSelectionText(text).c_str());
+                deleteSelection(text, changed);
+            }
+        }
+        if ((io.KeyCtrl || io.KeySuper) && ImGui::IsKeyPressed(ImGuiKey_V)) {
+            const char* clip = ImGui::GetClipboardText();
+            if (clip && *clip) {
+                insertText(text, std::string(clip), changed);
+            }
+        }
+    }
+
+    std::string getSelectionText(const std::string& text) const {
+        if (!hasSelection()) return "";
+        int a = std::min(selStart_, selEnd_);
+        int b = std::max(selStart_, selEnd_);
+        if (a < 0 || b > (int)text.size() || a >= b) return "";
+        return text.substr(a, b - a);
+    }
+
+    void selectWordAt(const std::string& text, int pos) {
+        if (pos < 0 || pos > (int)text.size()) return;
+        auto isWord = [](char c) { return std::isalnum((unsigned char)c) || c == '_'; };
+        int start = pos;
+        int end = pos;
+        while (start > 0 && isWord(text[start - 1])) --start;
+        while (end < (int)text.size() && isWord(text[end])) ++end;
+        selStart_ = start;
+        selEnd_ = end;
+        cursor_ = end;
     }
 };

editor/tests/step80_test.cpp

@@ -0,0 +1,132 @@
+// Step 80 TDD Test: Scroll, selection, clipboard
+//
+// Tests:
+// 1. Ctrl+A then Ctrl+C copies full buffer to clipboard
+// 2. Ctrl+X cuts selection to clipboard
+// 3. Ctrl+V pastes clipboard at cursor
+
+#include <cassert>
+#include <iostream>
+#include <string>
+#include "imgui.h"
+#include "CodeEditorWidget.h"
+#include "EditorMode.h"
+
+static std::string g_clipboard;
+
+static void SetClipboardText(void*, const char* text) {
+    g_clipboard = text ? text : "";
+}
+
+static const char* GetClipboardText(void*) {
+    return g_clipboard.c_str();
+}
+
+static void beginFrame() {
+    ImGuiIO& io = ImGui::GetIO();
+    io.DisplaySize = ImVec2(800, 600);
+    io.DeltaTime = 1.0f / 60.0f;
+    ImGui::NewFrame();
+}
+
+static void endFrame() {
+    ImGui::Render();
+}
+
+static void queueCtrlKey(ImGuiKey key) {
+    ImGuiIO& io = ImGui::GetIO();
+    io.AddKeyEvent(ImGuiKey_LeftCtrl, true);
+    io.AddKeyEvent(key, true);
+}
+
+int main() {
+    int passed = 0;
+    int failed = 0;
+
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGui::StyleColorsDark();
+    ImGuiIO& io = ImGui::GetIO();
+    io.Fonts->AddFontDefault();
+    io.Fonts->Build();
+    io.SetClipboardTextFn = SetClipboardText;
+    io.GetClipboardTextFn = GetClipboardText;
+
+    // --- Test 1: Ctrl+A then Ctrl+C copies full text ---
+    {
+        g_clipboard.clear();
+        beginFrame();
+        ImGui::SetNextWindowFocus();
+        ImGui::Begin("TestWindow");
+        CodeEditorWidget widget;
+        std::string text = "abc";
+        std::vector<HighlightSpan> spans;
+        CodeEditorOptions opts;
+
+        queueCtrlKey(ImGuiKey_A);
+        queueCtrlKey(ImGuiKey_C);
+
+        CodeEditorResult res = widget.render("##editor", text, spans, opts, ImVec2(300, 200), ImGui::GetFont());
+        (void)res;
+        ImGui::End();
+        endFrame();
+
+        assert(g_clipboard == "abc" && "Clipboard should contain full text");
+        std::cout << "Test 1 PASS: Ctrl+A/C copies text" << std::endl;
+        ++passed;
+    }
+
+    // --- Test 2: Ctrl+X cuts selection ---
+    {
+        g_clipboard.clear();
+        beginFrame();
+        ImGui::SetNextWindowFocus();
+        ImGui::Begin("TestWindow2");
+        CodeEditorWidget widget;
+        std::string text = "hello";
+        std::vector<HighlightSpan> spans;
+        CodeEditorOptions opts;
+
+        queueCtrlKey(ImGuiKey_A);
+        queueCtrlKey(ImGuiKey_X);
+
+        CodeEditorResult res = widget.render("##editor2", text, spans, opts, ImVec2(300, 200), ImGui::GetFont());
+        (void)res;
+        ImGui::End();
+        endFrame();
+
+        assert(g_clipboard == "hello" && "Clipboard should contain cut text");
+        assert(text.empty() && "Text should be empty after cut");
+        std::cout << "Test 2 PASS: Ctrl+X cuts selection" << std::endl;
+        ++passed;
+    }
+
+    // --- Test 3: Ctrl+V pastes clipboard ---
+    {
+        g_clipboard = "zz";
+        beginFrame();
+        ImGui::SetNextWindowFocus();
+        ImGui::Begin("TestWindow3");
+        CodeEditorWidget widget;
+        std::string text = "";
+        std::vector<HighlightSpan> spans;
+        CodeEditorOptions opts;
+        widget.setCursor(0);
+
+        queueCtrlKey(ImGuiKey_V);
+
+        CodeEditorResult res = widget.render("##editor3", text, spans, opts, ImVec2(300, 200), ImGui::GetFont());
+        (void)res;
+        ImGui::End();
+        endFrame();
+
+        assert(text == "zz" && "Paste should insert clipboard contents");
+        std::cout << "Test 3 PASS: Ctrl+V pastes" << std::endl;
+        ++passed;
+    }
+
+    ImGui::DestroyContext();
+
+    std::cout << "\n=== Step 80 Results: " << passed << " passed, " << failed << " failed ===" << std::endl;
+    return failed > 0 ? 1 : 0;
+}