Spreadsheet: Implement infinit-scroll for columns

This naturally also implements multi-char columns, and also integrates
it into the js runtime (such columns can be named in ranges too).

Applications/Spreadsheet/JSIntegration.cpp

@@ -83,6 +83,8 @@ void SheetGlobalObject::initialize()
     GlobalObject::initialize();
     define_native_function("parse_cell_name", parse_cell_name, 1);
     define_native_function("current_cell_position", current_cell_position, 0);
+    define_native_function("column_arithmetic", column_arithmetic, 2);
+    define_native_function("column_index", column_index, 1);
 }
 
 JS_DEFINE_NATIVE_FUNCTION(SheetGlobalObject::parse_cell_name)
@@ -137,6 +139,82 @@ JS_DEFINE_NATIVE_FUNCTION(SheetGlobalObject::current_cell_position)
     return object;
 }
 
+JS_DEFINE_NATIVE_FUNCTION(SheetGlobalObject::column_index)
+{
+    if (vm.argument_count() != 2) {
+        vm.throw_exception<JS::TypeError>(global_object, "Expected exactly one argument to column_index()");
+        return {};
+    }
+
+    auto column_name = vm.argument(0);
+    if (!column_name.is_string()) {
+        vm.throw_exception<JS::TypeError>(global_object, JS::ErrorType::NotA, "String");
+        return {};
+    }
+
+    auto& column_name_str = column_name.as_string().string();
+
+    auto* this_object = vm.this_value(global_object).to_object(global_object);
+    if (!this_object)
+        return JS::js_null();
+
+    if (StringView("SheetGlobalObject") != this_object->class_name()) {
+        vm.throw_exception<JS::TypeError>(global_object, JS::ErrorType::NotA, "SheetGlobalObject");
+        return {};
+    }
+
+    auto sheet_object = static_cast<SheetGlobalObject*>(this_object);
+    auto& sheet = sheet_object->m_sheet;
+    auto column_index = sheet.column_index(column_name_str);
+    if (!column_index.has_value()) {
+        vm.throw_exception(global_object, JS::TypeError::create(global_object, String::formatted("'{}' is not a valid column", column_name_str)));
+        return {};
+    }
+
+    return JS::Value((i32)column_index.value());
+}
+
+JS_DEFINE_NATIVE_FUNCTION(SheetGlobalObject::column_arithmetic)
+{
+    if (vm.argument_count() != 2) {
+        vm.throw_exception<JS::TypeError>(global_object, "Expected exactly two arguments to column_arithmetic()");
+        return {};
+    }
+
+    auto column_name = vm.argument(0);
+    if (!column_name.is_string()) {
+        vm.throw_exception<JS::TypeError>(global_object, JS::ErrorType::NotA, "String");
+        return {};
+    }
+
+    auto& column_name_str = column_name.as_string().string();
+
+    auto offset = vm.argument(1).to_number(global_object);
+    if (!offset.is_number())
+        return {};
+
+    auto offset_number = offset.as_i32();
+
+    auto* this_object = vm.this_value(global_object).to_object(global_object);
+    if (!this_object)
+        return JS::js_null();
+
+    if (StringView("SheetGlobalObject") != this_object->class_name()) {
+        vm.throw_exception<JS::TypeError>(global_object, JS::ErrorType::NotA, "SheetGlobalObject");
+        return {};
+    }
+
+    auto sheet_object = static_cast<SheetGlobalObject*>(this_object);
+    auto& sheet = sheet_object->m_sheet;
+    auto new_column = sheet.column_arithmetic(column_name_str, offset_number);
+    if (!new_column.has_value()) {
+        vm.throw_exception(global_object, JS::TypeError::create(global_object, String::formatted("'{}' is not a valid column", column_name_str)));
+        return {};
+    }
+
+    return JS::js_string(vm, new_column.release_value());
+}
+
 WorkbookObject::WorkbookObject(Workbook& workbook)
     : JS::Object(*JS::Object::create_empty(workbook.global_object()))
     , m_workbook(workbook)

Applications/Spreadsheet/JSIntegration.h

@@ -46,6 +46,8 @@ public:
 
     JS_DECLARE_NATIVE_FUNCTION(parse_cell_name);
     JS_DECLARE_NATIVE_FUNCTION(current_cell_position);
+    JS_DECLARE_NATIVE_FUNCTION(column_index);
+    JS_DECLARE_NATIVE_FUNCTION(column_arithmetic);
 
 private:
     Sheet& m_sheet;

Applications/Spreadsheet/Spreadsheet.cpp

@@ -99,28 +99,57 @@ size_t Sheet::add_row()
     return m_rows++;
 }
 
+static String convert_to_string(size_t value, unsigned base = 26, StringView map = {})
+{
+    if (map.is_null())
+        map = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+    ASSERT(base >= 2 && base <= map.length());
+
+    // The '8 bits per byte' assumption may need to go?
+    Array<char, round_up_to_power_of_two(sizeof(size_t) * 8 + 1, 2)> buffer;
+    size_t i = 0;
+    do {
+        buffer[i++] = map[value % base];
+        value /= base;
+    } while (value > 0);
+
+    // NOTE: Weird as this may seem, the thing that comes after 'A' is 'AA', which as a number would be '00'
+    //       to make this work, only the most significant digit has to be in a range of (1..25) as opposed to (0..25),
+    //       but only if it's not the only digit in the string.
+    if (i > 1)
+        --buffer[i - 1];
+
+    for (size_t j = 0; j < i / 2; ++j)
+        swap(buffer[j], buffer[i - j - 1]);
+
+    return String { ReadonlyBytes(buffer.data(), i) };
+}
+
+static size_t convert_from_string(StringView str, unsigned base = 26, StringView map = {})
+{
+    if (map.is_null())
+        map = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+    ASSERT(base >= 2 && base <= map.length());
+
+    size_t value = 0;
+    for (size_t i = str.length(); i > 0; --i) {
+        auto digit_value = map.find_first_of(str[i - 1]).value_or(0);
+        // NOTE: Refer to the note in `convert_to_string()'.
+        if (i == str.length() && str.length() > 1)
+            ++digit_value;
+        value = value * base + digit_value;
+    }
+
+    return value;
+}
+
 String Sheet::add_column()
 {
-    if (m_current_column_name_length == 0) {
-        m_current_column_name_length = 1;
-        m_columns.append("A");
-        return "A";
-    }
-
-    if (m_current_column_name_length == 1) {
-        auto last_char = m_columns.last()[0];
-        if (last_char == 'Z') {
-            m_current_column_name_length = 2;
-            m_columns.append("AA");
-            return "AA";
-        }
-
-        last_char++;
-        m_columns.append({ &last_char, 1 });
-        return m_columns.last();
-    }
-
-    TODO();
+    auto next_column = convert_to_string(m_columns.size());
+    m_columns.append(next_column);
+    return next_column;
 }
 
 void Sheet::update()
@@ -207,6 +236,31 @@ Optional<Position> Sheet::parse_cell_name(const StringView& name)
     return Position { col, row.to_uint().value() };
 }
 
+Optional<size_t> Sheet::column_index(const StringView& column_name) const
+{
+    auto index = convert_from_string(column_name);
+    if (m_columns.size() <= index || m_columns[index] != column_name)
+        return {};
+
+    return index;
+}
+
+Optional<String> Sheet::column_arithmetic(const StringView& column_name, int offset)
+{
+    auto maybe_index = column_index(column_name);
+    if (!maybe_index.has_value())
+        return {};
+
+    auto index = maybe_index.value() + offset;
+    if (m_columns.size() > index)
+        return m_columns[index];
+
+    for (size_t i = m_columns.size(); i <= index; ++i)
+        add_column();
+
+    return m_columns.last();
+}
+
 Cell* Sheet::from_url(const URL& url)
 {
     auto maybe_position = position_from_url(url);
@@ -335,6 +389,11 @@ RefPtr<Sheet> Sheet::from_json(const JsonObject& object, Workbook& workbook)
         return IterationDecision::Continue;
     });
 
+    if (sheet->m_columns.size() < default_column_count && sheet->columns_are_standard()) {
+        for (size_t i = sheet->m_columns.size(); i < default_column_count; ++i)
+            sheet->add_column();
+    }
+
     auto cells = object.get("cells").as_object();
     auto json = sheet->interpreter().global_object().get("JSON");
     auto& parse_function = json.as_object().get("parse").as_function();
@@ -425,15 +484,28 @@ Position Sheet::written_data_bounds() const
 {
     Position bound;
     for (auto& entry : m_cells) {
-        if (entry.key.row > bound.row)
+        if (entry.key.row >= bound.row)
             bound.row = entry.key.row;
-        if (entry.key.column > bound.column)
+        if (entry.key.column >= bound.column)
             bound.column = entry.key.column;
     }
 
     return bound;
 }
 
+/// The sheet is allowed to have nonstandard column names
+/// this checks whether all existing columns are 'standard'
+/// (i.e. as generated by 'convert_to_string()'
+bool Sheet::columns_are_standard() const
+{
+    for (size_t i = 0; i < m_columns.size(); ++i) {
+        if (m_columns[i] != convert_to_string(i))
+            return false;
+    }
+
+    return true;
+}
+
 JsonObject Sheet::to_json() const
 {
     JsonObject object;
@@ -448,12 +520,13 @@ JsonObject Sheet::to_json() const
 
     auto bottom_right = written_data_bounds();
 
-    auto columns = JsonArray();
-    for (auto& column : m_columns)
-        columns.append(column);
-    object.set("columns", move(columns));
-
-    object.set("rows", bottom_right.row);
+    if (!columns_are_standard()) {
+        auto columns = JsonArray();
+        for (auto& column : m_columns)
+            columns.append(column);
+        object.set("columns", move(columns));
+    }
+    object.set("rows", bottom_right.row + 1);
 
     JsonObject cells;
     for (auto& it : m_cells) {
@@ -520,12 +593,21 @@ Vector<Vector<String>> Sheet::to_xsv() const
     auto bottom_right = written_data_bounds();
 
     // First row = headers.
-    data.append(m_columns);
+    size_t column_count = m_columns.size();
+    if (columns_are_standard()) {
+        column_count = convert_from_string(bottom_right.column) + 1;
+        Vector<String> cols;
+        for (size_t i = 0; i < column_count; ++i)
+            cols.append(m_columns[i]);
+        data.append(move(cols));
+    } else {
+        data.append(m_columns);
+    }
 
     for (size_t i = 0; i <= bottom_right.row; ++i) {
         Vector<String> row;
-        row.resize(m_columns.size());
-        for (size_t j = 0; j < m_columns.size(); ++j) {
+        row.resize(column_count);
+        for (size_t j = 0; j < column_count; ++j) {
             auto cell = at({ m_columns[j], i });
             if (cell)
                 row[j] = cell->typed_display();
@@ -546,6 +628,10 @@ RefPtr<Sheet> Sheet::from_xsv(const Reader::XSV& xsv, Workbook& workbook)
     sheet->m_columns = cols;
     for (size_t i = 0; i < max(rows, Sheet::default_row_count); ++i)
         sheet->add_row();
+    if (sheet->columns_are_standard()) {
+        for (size_t i = sheet->m_columns.size(); i < Sheet::default_column_count; ++i)
+            sheet->add_column();
+    }
 
     for (auto row : xsv) {
         for (size_t i = 0; i < cols.size(); ++i) {

Applications/Spreadsheet/Spreadsheet.h

@@ -52,6 +52,8 @@ public:
     ~Sheet();
 
     static Optional<Position> parse_cell_name(const StringView&);
+    Optional<size_t> column_index(const StringView& column_name) const;
+    Optional<String> column_arithmetic(const StringView& column_name, int offset);
 
     Cell* from_url(const URL&);
     const Cell* from_url(const URL& url) const { return const_cast<Sheet*>(this)->from_url(url); }
@@ -130,6 +132,8 @@ public:
     /// Gives the bottom-right corner of the smallest bounding box containing all the written data.
     Position written_data_bounds() const;
 
+    bool columns_are_standard() const;
+
 private:
     explicit Sheet(Workbook&);
     explicit Sheet(const StringView& name, Workbook&);
@@ -145,8 +149,6 @@ private:
 
     Cell* m_current_cell_being_evaluated { nullptr };
 
-    size_t m_current_column_name_length { 0 };
-
     HashTable<Cell*> m_visited_cells_in_update;
 };
 

Applications/Spreadsheet/SpreadsheetView.cpp

@@ -62,10 +62,15 @@ void InfinitelyScrollableTableView::did_scroll()
 {
     TableView::did_scroll();
     auto& vscrollbar = vertical_scrollbar();
+    auto& hscrollbar = horizontal_scrollbar();
     if (vscrollbar.is_visible() && vscrollbar.value() == vscrollbar.max()) {
         if (on_reaching_vertical_end)
             on_reaching_vertical_end();
     }
+    if (hscrollbar.is_visible() && hscrollbar.value() == hscrollbar.max()) {
+        if (on_reaching_horizontal_end)
+            on_reaching_horizontal_end();
+    }
 }
 
 void SpreadsheetView::update_with_model()
@@ -92,6 +97,15 @@ SpreadsheetView::SpreadsheetView(Sheet& sheet)
         };
         update_with_model();
     };
+    m_table_view->on_reaching_horizontal_end = [&]() {
+        for (size_t i = 0; i < 10; ++i) {
+            m_sheet->add_column();
+            auto last_column_index = m_sheet->column_count() - 1;
+            m_table_view->set_column_width(last_column_index, 50);
+            m_table_view->set_column_header_alignment(last_column_index, Gfx::TextAlignment::Center);
+        }
+        update_with_model();
+    };
 
     set_focus_proxy(m_table_view);
 

Applications/Spreadsheet/SpreadsheetView.h

@@ -83,6 +83,7 @@ class InfinitelyScrollableTableView : public GUI::TableView {
     C_OBJECT(InfinitelyScrollableTableView)
 public:
     Function<void()> on_reaching_vertical_end;
+    Function<void()> on_reaching_horizontal_end;
 
 private:
     virtual void did_scroll() override;

Base/res/js/Spreadsheet/runtime.js

@@ -27,20 +27,20 @@ class Position {
 
     left(how_many) {
         how_many = how_many ?? 1;
-        const column = Math.min(
-            "Z".charCodeAt(0),
-            Math.max("A".charCodeAt(0), this.column.charCodeAt(0) - how_many)
+        return new Position(
+            this.sheet.column_arithmetic(this.column, -how_many),
+            this.row,
+            this.sheet
         );
-        return new Position(String.fromCharCode(column), this.row, this.sheet);
     }
 
     right(how_many) {
         how_many = how_many ?? 1;
-        const column = Math.min(
-            "Z".charCodeAt(0),
-            Math.max("A".charCodeAt(0), this.column.charCodeAt(0) + how_many)
+        return new Position(
+            this.sheet.column_arithmetic(this.column, how_many),
+            this.row,
+            this.sheet
         );
-        return new Position(String.fromCharCode(column), this.row, this.sheet);
     }
 
     with_column(value) {
@@ -78,22 +78,21 @@ function range(start, end, columnStep, rowStep) {
         end = parse_cell_name(end) ?? start;
     }
 
-    if (end.column.length > 1 || start.column.length > 1)
-        throw new TypeError("Only single-letter column names are allowed (TODO)");
-
     const cells = [];
 
-    for (
-        let col = Math.min(start.column.charCodeAt(0), end.column.charCodeAt(0));
-        col <= Math.max(start.column.charCodeAt(0), end.column.charCodeAt(0));
-        col += columnStep
-    ) {
+    const start_column_index = column_index(start.column);
+    const end_column_index = column_index(end.column);
+    const start_column = start_column_index > end_column_index ? end.column : start.column;
+    const distance = Math.abs(start_column_index - end_column_index);
+
+    for (let col = 0; col <= distance; col += columnStep) {
+        const column = column_arithmetic(start_column, col);
         for (
             let row = Math.min(start.row, end.row);
             row <= Math.max(start.row, end.row);
             row += rowStep
         ) {
-            cells.push(String.fromCharCode(col) + row);
+            cells.push(column + row);
         }
     }
 
@@ -345,6 +344,7 @@ range.__documentation = JSON.stringify({
     examples: {
         'range("A1", "C4")': "Generate a range A1:C4",
         'range("A1", "C4", 2)': "Generate a range A1:C4, skipping every other column",
+        'range("AA1", "AC4", 2)': "Generate a range AA1:AC4, skipping every other column",
     },
 });