TermTk.TTkGui.textdocument

TTkTextDocument

class TTkTextDocument(*args, **kwargs)[source]

Undo,Redo Logic

Old:

_snapshotId: = last saved/undo/redo state: 3 = doc4
_snapshots:: [doc1, doc2, doc3, doc4, doc5, doc6, …]

New:

SnapshotId:: 2
Snapshots: _lastSnap _dataLines (unstaged): ╒═══╕ ╒═══╕ ╒═══╕ ╒═══╕ ╒═══╕ ╒═══╕ │ 0 │ │ 1 │ │ 2 │ │ 3 │ │ 4 │ │ 5 │ └───┘ └───┘ └───┘ └───┘ └───┘ └───┘
Cursors:: c0, c1, c2, c3, c4 = _lastCursor
Diffs:: [ d01, d12, d23, d34 ] = Forward Diffs [ d10, d21, d32, d43 ] = Backward Diffs
Slices: = common txt slices between snapshots: [ s01, s12, s23, s34 ]
Data Structure: ╔═══════════════╗ ╔═══════════════╗ ║ Snapshot B ║ ┌─────────────>║ Snapshot C ║ ╟───────────────╢ │ ╟───────────────╢ ║ _nextDiff ║──────┐ │ ║ _nextDiff ║───> Next snapshot

┌───║ _prevDiff ║ │ │ ┌───║ _prevDiff ║ or Null if at the end │ ╚═══════════════╝ │ │ │ ╚═══════════════╝ V A V │ V

╔═══════════════╗ │ ╔═══════════════╗ ╔═══════════════╗ ║ Diff B->A ║ │ ║ Diff B->C ║ ║ Diff C->B ║ ╟───────────────╢ │ ╟───────────────╢ ╟───────────────╢ ║ slice = txtBA ║ │ ║ slice = txtBC ║ ║ slice = txtBA ║ ║ snap ║ │ ║ snap ║ ║ snap ║ ╚═══════════════╝ │ ╚═══════════════╝ ╚═══════════════╝

│ │ └─────────────────────────────┘