# Task

Tasks are the central element in task models. A task is defined by its goal (expressed by the name given to the task) and the procedure to reach this goal (detailed in the decomposition associated to the task). Tasks are decomposed until you reach the level of elementary tasks, i.e. tasks that will not be decomposed further. Elementary tasks often correspond to an action, for example button clicks.

Task order may be important:

- if it is not, tasks are said to be parallel (i.e. no link between them) and the task model will show no link (arrow) between tasks.
- if it is important, when describing the task, the ordering of the actions (or sub-level tasks) will be like :

- do T1 then T2 - actions will then be linked by arrows that will express the sequence.
- do either T1 or T2 - the actions will then be linked by the boolean connector XOR
- do T1 or/and do T2 - the actions will then be linked by boolean connectors OR or AND

Each task consists of attributes organised into 2 parts :

1. the core field
2. the context field.

You can also consult Diane+H the formalisms used.

## Task Core

Task core refers to the central part of a task which is independent of circumstances in which the task is performed. The fields belonging to the task core are :

- name
- semantics
- style
- composite
- decomposition
- comment

## Task Context

Task context captures the context in which the task is performed, such as precondition and feedback. The fields belonging to the task context are :

- dirty
- mandatory
- minCard
- maxCard
- precondition
- feedback
- terminal