| 🛟 Updated. 28d5985 k33g 18h ago | 1 | package editor |
| 2 | |
| 3 | import ( |
| 4 | "github.com/gdamore/tcell/v2" |
| 5 | |
| 📦 Turbo Core f3ade8d k33g 10h ago | 6 | "rickub.com/turbo-editors/turbo-core/buffer" |
| 🛟 Updated. 28d5985 k33g 18h ago | 7 | ) |
| 8 | |
| 9 | // HandleKey turns a key press into a movement, a selection or an edit. |
| 10 | // |
| 11 | // The bindings follow Turbo C where it still makes sense — Ctrl-Insert to |
| 12 | // copy, Shift-Insert to paste — and modern habits where it does not, since |
| 13 | // Ctrl-Z for undo is what fingers now expect. |
| 14 | func (v *View) HandleKey(ev *tcell.EventKey) bool { |
| 15 | if v.handleMovement(ev) || v.handleClipboard(ev) || v.handleEditing(ev) { |
| 16 | return true |
| 17 | } |
| 18 | return v.handleTyping(ev) |
| 19 | } |
| 20 | |
| 21 | // handleMovement deals with the keys that only move the cursor, extending the |
| 22 | // selection when Shift is held. |
| 23 | func (v *View) handleMovement(ev *tcell.EventKey) bool { |
| 24 | move := v.movementFor(ev) |
| 25 | if move == nil { |
| 26 | return false |
| 27 | } |
| 28 | |
| 29 | if ev.Modifiers()&tcell.ModShift != 0 { |
| 30 | v.buf.Extend(move) |
| 31 | } else { |
| 32 | move() |
| 33 | v.buf.ClearSelection() |
| 34 | } |
| 35 | |
| 36 | v.EnsureCursorVisible() |
| 37 | v.notifyCursor() |
| 38 | return true |
| 39 | } |
| 40 | |
| 41 | // movementFor returns the cursor movement a key asks for, or nil when the key |
| 42 | // is not a movement at all. |
| 43 | // |
| 44 | // Ctrl widens three of them from a character to a word or to the whole file, |
| 45 | // which is why the table is built here rather than being a package variable. |
| 46 | func (v *View) movementFor(ev *tcell.EventKey) func() { |
| 47 | ctrl := ev.Modifiers()&tcell.ModCtrl != 0 |
| 48 | |
| 49 | var move func() |
| 50 | switch ev.Key() { |
| 51 | case tcell.KeyLeft: |
| 52 | move = pick(ctrl, v.buf.MoveWordLeft, v.buf.MoveLeft) |
| 53 | case tcell.KeyRight: |
| 54 | move = pick(ctrl, v.buf.MoveWordRight, v.buf.MoveRight) |
| 55 | case tcell.KeyUp: |
| 56 | move = v.buf.MoveUp |
| 57 | case tcell.KeyDown: |
| 58 | move = v.buf.MoveDown |
| 59 | case tcell.KeyHome: |
| 60 | move = pick(ctrl, v.buf.MoveBufferStart, v.buf.MoveLineStart) |
| 61 | case tcell.KeyEnd: |
| 62 | move = pick(ctrl, v.buf.MoveBufferEnd, v.buf.MoveLineEnd) |
| 63 | case tcell.KeyPgUp: |
| 64 | move = func() { v.movePage(-1) } |
| 65 | case tcell.KeyPgDn: |
| 66 | move = func() { v.movePage(+1) } |
| 67 | } |
| 68 | return move |
| 69 | } |
| 70 | |
| 71 | // pick returns whichever of two movements the modifier calls for. |
| 72 | func pick(modified bool, withModifier, plain func()) func() { |
| 73 | if modified { |
| 74 | return withModifier |
| 75 | } |
| 76 | return plain |
| 77 | } |
| 78 | |
| 79 | // movePage moves the cursor and the view by one screenful. |
| 80 | func (v *View) movePage(direction int) { |
| 81 | page := max(v.VisibleLines(), 1) |
| 82 | cursor := v.buf.Cursor() |
| 83 | |
| 84 | v.buf.SetCursor(buffer.Position{Line: cursor.Line + direction*page, Col: cursor.Col}) |
| 85 | v.ScrollBy(direction * page) |
| 86 | } |
| 87 | |
| 88 | // handleClipboard deals with cut, copy, paste and select-all, in both their |
| 89 | // Turbo C and their modern spellings. |
| 90 | func (v *View) handleClipboard(ev *tcell.EventKey) bool { |
| 91 | shift := ev.Modifiers()&tcell.ModShift != 0 |
| 92 | ctrl := ev.Modifiers()&tcell.ModCtrl != 0 |
| 93 | |
| 94 | switch { |
| 95 | case ev.Key() == tcell.KeyCtrlC, ev.Key() == tcell.KeyInsert && ctrl: |
| 96 | v.Copy() |
| 97 | case ev.Key() == tcell.KeyCtrlX, ev.Key() == tcell.KeyDelete && shift: |
| 98 | v.Cut() |
| 99 | case ev.Key() == tcell.KeyCtrlV, ev.Key() == tcell.KeyInsert && shift: |
| 100 | v.Paste() |
| 101 | case ev.Key() == tcell.KeyCtrlA: |
| 102 | v.SelectAll() |
| 103 | default: |
| 104 | return false |
| 105 | } |
| 106 | |
| 107 | v.EnsureCursorVisible() |
| 108 | return true |
| 109 | } |
| 110 | |
| 111 | // handleEditing deals with the keys that change the text without inserting a |
| 112 | // printable character. |
| 113 | func (v *View) handleEditing(ev *tcell.EventKey) bool { |
| 114 | if v.handleCommand(ev) { |
| 115 | return true |
| 116 | } |
| 117 | |
| 118 | switch ev.Key() { |
| 119 | case tcell.KeyEnter: |
| 120 | v.buf.InsertNewlineAndIndent() |
| 121 | case tcell.KeyBackspace, tcell.KeyBackspace2: |
| 122 | v.buf.Backspace() |
| 123 | case tcell.KeyDelete: |
| 124 | v.buf.Delete() |
| 125 | default: |
| 126 | return false |
| 127 | } |
| 128 | |
| 129 | v.EnsureCursorVisible() |
| 130 | v.notifyChange() |
| 131 | return true |
| 132 | } |
| 133 | |
| 134 | // handleCommand deals with the keys that ask the view to do something rather |
| 135 | // than to change the text under the cursor. Each of them reports its own |
| 136 | // change, so none of them falls through to the notification below. |
| 137 | func (v *View) handleCommand(ev *tcell.EventKey) bool { |
| 138 | switch ev.Key() { |
| 139 | case tcell.KeyTab: |
| 140 | v.Indent() |
| 141 | case tcell.KeyBacktab: |
| 142 | v.Unindent() |
| 143 | case tcell.KeyCtrlZ: |
| 144 | v.Undo() |
| 145 | case tcell.KeyCtrlR: |
| 146 | v.Redo() |
| 147 | // Ctrl-Y deletes a line and Ctrl-N inserts one, as they did in Turbo C and |
| 148 | // Turbo Pascal. Ctrl-Y is why redo moved to Ctrl-R: it was the redo key |
| 149 | // here for a while, and this is the one place the two claims collide. |
| 150 | // Ctrl-Shift-Z, the obvious alternative for redo, is not a key a terminal |
| 151 | // can deliver — it arrives as plain Ctrl-Z. |
| 152 | case tcell.KeyCtrlY: |
| 153 | v.DeleteLine() |
| 154 | case tcell.KeyCtrlN: |
| 155 | v.InsertLine() |
| 156 | case tcell.KeyCtrlSpace: |
| 157 | v.requestCompletion() |
| 158 | default: |
| 159 | return false |
| 160 | } |
| 161 | |
| 162 | v.EnsureCursorVisible() |
| 163 | return true |
| 164 | } |
| 165 | |
| 166 | // handleTyping inserts a printable character. |
| 167 | func (v *View) handleTyping(ev *tcell.EventKey) bool { |
| 168 | if ev.Key() != tcell.KeyRune || ev.Modifiers()&(tcell.ModAlt|tcell.ModCtrl) != 0 { |
| 169 | return false |
| 170 | } |
| 171 | |
| 172 | v.buf.InsertRune(ev.Rune()) |
| 173 | v.EnsureCursorVisible() |
| 174 | v.notifyChange() |
| 175 | |
| 176 | // A dot is where a completion list is most useful, so asking for one is |
| 177 | // automatic there and manual everywhere else. |
| 178 | if ev.Rune() == '.' { |
| 179 | v.requestCompletion() |
| 180 | } |
| 181 | return true |
| 182 | } |
| 183 | |
| 184 | // requestCompletion asks the owner to offer a completion list. |
| 185 | func (v *View) requestCompletion() { |
| 186 | if v.OnCompletionRequest != nil { |
| 187 | v.OnCompletionRequest() |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | // HandleMouse places the cursor, extends the selection by dragging, and |
| 192 | // scrolls with the wheel. |
| 193 | func (v *View) HandleMouse(ev *tcell.EventMouse) bool { |
| 194 | x, y := ev.Position() |
| 195 | |
| 196 | switch ev.Buttons() { |
| 197 | case tcell.WheelUp: |
| 198 | v.ScrollBy(-wheelStep) |
| 199 | case tcell.WheelDown: |
| 200 | v.ScrollBy(+wheelStep) |
| 201 | case tcell.Button1: |
| 202 | v.pressOrDrag(x, y) |
| 203 | case tcell.ButtonNone: |
| 204 | v.selecting = false |
| 205 | return false |
| 206 | default: |
| 207 | return false |
| 208 | } |
| 209 | return true |
| 210 | } |
| 211 | |
| 212 | // wheelStep is how many lines one notch of the mouse wheel scrolls. |
| 213 | const wheelStep = 3 |
| 214 | |
| 215 | // pressOrDrag puts the cursor where the mouse is, starting a selection on the |
| 216 | // first event of a drag and extending it on the ones that follow. |
| 217 | // |
| 218 | // A press is only a *press* when nothing is being dragged: tcell sends Button1 |
| 219 | // for every event of a drag too, and counting those as clicks would turn a |
| 220 | // slow drag into a double click. |
| 221 | func (v *View) pressOrDrag(x, y int) { |
| 222 | position := v.positionAt(x, y) |
| 223 | |
| 224 | switch { |
| 225 | case v.selecting: |
| 226 | v.buf.SetCursorKeepingSelection(position) |
| 227 | case v.countClick(position) >= 2: |
| 228 | // A second press on the same cell selects the word under it, and the |
| 229 | // drag carries on from there: holding and moving after a double click |
| 230 | // extends from the **start of the word**, by character. That is not |
| 231 | // the word-by-word drag a large editor does — it is the cheap half of |
| 232 | // it, and it beats the alternative, which is the word collapsing back |
| 233 | // to a single character the moment the pointer twitches. |
| 234 | v.buf.SelectWord(position) |
| 235 | v.selecting = true |
| 236 | default: |
| 237 | v.buf.SetCursor(position) |
| 238 | v.buf.StartSelection() |
| 239 | v.selecting = true |
| 240 | } |
| 241 | |
| 242 | v.EnsureCursorVisible() |
| 243 | v.notifyCursor() |
| 244 | } |