LivePanels.Canvas.History (livepanels v0.1.0)

Actor-scoped undo/redo history projection returned by LivePanels.Canvas.Read.history/1.

Applications may inspect this struct for read-only UI state such as enabling undo and redo controls. This module also owns the socket-first and transaction-first history command helpers.

Summary

Types

command_result()

effect()

Opaque versioned history effect captured while reducers build a patch entry.

effect_capture()

Opaque history effect capture options.

entry()

entry_delta()

patch()

Opaque versioned history patch entry.

patch_side()

Opaque side of a versioned history patch entry.

socket()

t()

target()

First argument accepted by history command helpers.

Functions

can_redo?(history)

Returns whether the current history projection has an entry to redo.

can_undo?(history)

Returns whether the current history projection has an entry to undo.

entry_delta(entry)

Summarizes the layout impact of one history entry for app-owned activity UI.

redo(target)

Reapplies history and returns the command result.

redo!(target)

Reapplies the next entry in the current actor's canvas history.

redo_count(history)

Returns the number of redo entries in a history projection.

redo_entries(history)

Returns redo entries in next-first order.

undo(target)

Rewinds history and returns the command result.

undo!(target)

Rewinds the current actor's canvas history.

undo_count(history)

Returns the number of undo entries in a history projection.

undo_entries(history)

Returns undo entries in newest-first order.

Types

command_result()

@type command_result() :: LivePanels.Canvas.Command.result()

effect()

@type effect() :: map()

Opaque versioned history effect captured while reducers build a patch entry.

effect_capture()

@type effect_capture() :: map()

Opaque history effect capture options.

entry()

@type entry() :: patch()

entry_delta()

@type entry_delta() :: %{
  item_delta: integer(),
  item_total: non_neg_integer(),
  connector_delta: integer(),
  connector_total: non_neg_integer(),
  changed_items: non_neg_integer()
}

patch()

@type patch() :: map()

Opaque versioned history patch entry.

History entries are tagged maps using internal keys such as :__livepanels_history_patch__. Host code should use helper functions such as entry_delta/1, undo_entries/1, and redo_entries/1 instead of depending on the serialized map shape.

patch_side()

@type patch_side() :: map()

Opaque side of a versioned history patch entry.

socket()

@type socket() :: Phoenix.LiveView.Socket.t()

t()

@type t() :: %LivePanels.Canvas.History{future: [entry()], past: [entry()]}

target()

@type target() :: LivePanels.Canvas.command_target()

First argument accepted by history command helpers.

Pass a LiveView socket for a standalone command, or a LivePanels.Canvas.Transaction context inside LivePanels.Canvas.transaction/2.

Functions

can_redo?(history)

@spec can_redo?(t() | term()) :: boolean()

Returns whether the current history projection has an entry to redo.

can_undo?(history)

@spec can_undo?(t() | term()) :: boolean()

Returns whether the current history projection has an entry to undo.

entry_delta(entry)

@spec entry_delta(entry() | map()) :: entry_delta()

Summarizes the layout impact of one history entry for app-owned activity UI.

redo(target)

@spec redo(target()) :: command_result()

Reapplies history and returns the command result.

redo!(target)

@spec redo!(target()) :: target()

Reapplies the next entry in the current actor's canvas history.

redo_count(history)

@spec redo_count(t() | term()) :: non_neg_integer()

Returns the number of redo entries in a history projection.

redo_entries(history)

@spec redo_entries(t() | term()) :: [entry()]

Returns redo entries in next-first order.

undo(target)

@spec undo(target()) :: command_result()

Rewinds history and returns the command result.

undo!(target)

@spec undo!(target()) :: target()

Rewinds the current actor's canvas history.

undo_count(history)

@spec undo_count(t() | term()) :: non_neg_integer()

Returns the number of undo entries in a history projection.

undo_entries(history)

@spec undo_entries(t() | term()) :: [entry()]

Returns undo entries in newest-first order.