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Team_A_2

Sws

Conventions

  • Calligraphic letters (e.g. $\mathcal{P}$) represent types
  • Capital letters (e.g. $C$) represent sets
  • Lowercase letters (e.g. $b$) represent an instance of a type
  • Indexing: most interior index determines the type (e.g. $n_R$ is revision $R$ with revision number $n$)

Basic definitions

Pieces

A piece is a scan of a single physical scroll fragment.

  • Can be disabled/re-enabled (e.g. duplicates)
  • When disabled will be marked in compositions

$\mathcal{P}$: the set of all pieces

Composition members

A composition member is a piece along with a position (relative to the origin of the workspace) and rotation.

$\mathcal{M}$: the set of all possible composition members
$\mathcal{M} = \{(p,pos,rot)\,|\, p\in \mathcal{P}, pos\in Position, rot\in Double \}$
$Position = Double \times Double \times Integer$

The position includes a z-index which is used to determine how overlapping pieces are displayed.

A composition member can only be used in one composition.

Compositions

A composition consists of a set of 0 or more composition members and an annotation string.

$\mathcal{C}$: the set of all compositions
$\mathcal{C} = \{ (ann, members) \;|\; ann \in Annotation, members \subset \mathcal{M}\}$

An annotation is a string which may be empty and may contain newlines.
$Annotation = String$

Versioning system

Definitions (informal)

Branches

A branch has

  • a unique identifier
  • a sequence of revisions
    • initially one empty revision with revision number 0.

Revisions

A revision has

  • a set of compositions
  • a revision number.

Workspaces

A workspace is a local copy of a branch.

Definitions (formal)

Branches $\mathcal{B}$

  • sequence of revisions $R \subseteq \mathcal{R}$
  • unique identifier $i \in String$

Revisions $\mathcal{R}$

  • set of compositions $C \subseteq \mathcal{C}$
  • revision number $n \in \mathcal{N}$ (unique within branch)

Workspaces $\mathcal{W}$

representation of a branch in the compositor

  • set of compositions $C \subseteq \mathcal{C}$
  • branch $b \in \mathcal{B}$
  • revision number $n \in \mathcal{N}$

Uniqueness constraint

Revision

Piece uniqueness: pieces can only occur once.

Workspace

No piece uniqueness: pieces can occur in multiple compositions (conflicts can occur).

State/operations (informal)

Initial state

  • Only one branch, named "trunk".

Checkout

  • Create a new workspace from a branch
  • Optionally specify revision number

Update

  • Add all compositions from newer revisions in the branch to the workspace
  • Optionally specify revision number
  • Can result in conflicts

Import

  • Copy one or more compositions from another branch into the workspace
  • Can result in conflicts

Branch

  • Create a new branch as a copy of another branch
  • Optionally specify revision number

Commit

  • Stores the workspace as a new revision in the branch
  • Requires conflicts to be resolved fi rst (uniqueness constraint)
  • Requires workspace to be up-to-date (same revision as branch)
  • The revision number is the previous revision number increased by 1

State/operations (formal)

Bigbang

\begin{description} \item[Pre-state] $\emptyset$ \item[In-event] $bigbang() $ \item[Out-event] \item[Post-state] $ \{b | b_i = $ "trunk" $, b_R = \{ R | R_C = \emptyset, R_n = 0 \} \} $ \end{description}

Checkout

\begin{description} \item[Pre-state] $\mathcal{B}$ \item[In-event] $ checkout(b, n)$ \\ $ b \in \mathcal{B}, n_R \subseteq b_\mathcal{R} $ \item[Out-event] $ create (w | w_C = R_C, w_b = b, w_n = n) $ \item[Post-state] $\mathcal{B}$ \end{description}

Update

\begin{description} \item[Pre-state] $\mathcal{B}$ \item[In-event] $update(w) $ \\ $ w \in \mathcal{W}, w_b \in \mathcal{B} $ \item[Out-event] $modify (w| w_C = w_C \cup last(w_{b_R})_C, w_n = last(w_{b_R})_n ) $ \item[Post-state] $\mathcal{B}$ \end{description}

Import

\begin{description} \item[Pre-state] $\mathcal{B}$ \item[In-event] $import(b, n, c, w) $ \\ $ b \in \mathcal{B}, n_r \in b_\mathcal{R} , C \subseteq r_C , w \in \mathcal{W} $ \item[Out-event] $modify (w, w_C = w_C \cup R_C ) $ \item[Post-state] $\mathcal{B}$ \end{description}

Branch

\begin{description} \item[Pre-state] $\mathcal{B}$ \item[In-event] $branch(b, n, i) $ \\ $ b \in \mathcal{B}, n_R \in b_\mathcal{R}, i \in String $ \item[Out-event] - \item[Post-state] $\mathcal{B} \cup \{ b'| b'_i = i , b'_{R_C} = n_{R_C} , b'_{R_n} = 0 \} $ \end{description}

Commit

\begin{description} \item[Pre-state] $\mathcal{B}$ \item[In-event] $commit(w) $ \\ $ w \in \mathcal{W} , w_b \in \mathcal{B} $ \item[Out-event] - \item[Post-state] $ ( \mathcal{B} / b ) \cup \{ b' | b'_i = b_i, b'_R = b_R \cup $\\$ \{ R | R_C = w_C, b'_{R_n} = last(b_\mathcal{R})_n + 1 \} \} $ \end{description}