Simple conditions

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Simple conditions

A simple condition must adhere to the following syntax.

: [determinant] entity verb value

Elements between ``[]'' are optional.

A simple condition starts with an optional determinant followed by an entity, a verb, and a value. Notice that UCEd grammars are not case sensitive.

Possible determinants are ``a'', ``an'' and ``the''.
A condition may or may not start with a determinant with no difference in the meaning. For instance, the conditions 'User is logged in', 'A User is logged in', 'The User is logged in', and 'An User is logged in' are all equivalent. Notice that UCEd doesn't check that determinant are correctly used according to the English grammar.
An entity consists of one or more words specified as

$word_{1} \cdots word_{n}$

The sequence of words must correspond to a concept (an actor or the system under consideration), an attribute of a concept in the domain model, an instance of a concept, or a reference to an attribute of an instance.
Entities names are specified in extension.
- to refer to a concept (or system concept),
  the sequence used $word_{1} \cdots word_{n}$ needs to correspond to a concept as declared in the domain model,
- to refer to an attribute
  the sequence used $word_{1} \cdots word_{i} \cdots word_{n}$ needs to be such that $word_{1} \cdots word_{i}$ refers to an entity and $word_{i+1} \cdots word_{n}$ refers to an attribute of the entity as declared in the domain model,
- to refer to the component of a concept (an aggregate)
  the sequence used $word_{1} \cdots word_{i} \cdots word_{n}$ needs to be such that $word_{1} \cdots word_{i}$ refers to an entity and $word_{i+1} \cdots word_{n}$ refers to an aggregate of the entity as declared in the domain model,
- to refer to an instance
  the sequence used $word_{1} \cdots word_{i} \cdots word_{n}$ needs to be such that $word_{1} \cdots word_{i}$ refers to an entity and $word_{i+1} \cdots word_{n}$ refers to an instance of the entity as declared in the domain.
As examples,

the sequence ``User number of attempts'' must be used to refer to attribute ``number of attempts'' of concept ``User''

the sequence ``User Display'' must be used to refer to component ``Display'' of concept ``User''

the sequence ``User John'' must be used to refer to instance ``John'' of concept ``User''
The verb must be derived from ``to be'' or ``to have'', and the present tense must be used.
Therefore the only possible verb expressions are:

``is''

``isn't''

``is not''

``are''

``aren't''

``are not''

``has''

``hasn't''

``has not''

``have''

``haven't''

``have not''

As for determinants, UCEd does not check the correct English usage of verb expressions. As an example, ``User card is inserted'' and ``User card are inserted'' are equally valid.
A value is an entity qualifier.
A value may be one of the possible values of the condition entity, or specified as a general comparison.
- For possible values, the sequence of words used to refer to the value must be declared as a possible value of the entity in the domain model.
  As an example, for ``User identification is valid'', ``valid'' must be declared as a possible value of entity ``User identification''.
- For general comparisons, the syntax for value specification must adhere to the following
  comparator value
  The comparator must be one of the following: "", "", "", "", "", "", "greater than", "less than", "equal to", "different to", "greater or equal to", or "less or equal to".
  The value must be a sequence of words refering or not to a numerical value.
  When a comparison is used, the entity in the condition must be defined with no possible value listed in the domain model.
  As an example attribute ``number of attempts'' of concept ``User'' doesn't have any possible value in the PMSystem domain. This attribute can therefore be used in a condition such as ``User number of attempts is 5'' where a value is specified as a general comparison.
  On the other hand, suppose attribute ``identification'' has a set of possible values defined, only conditions involving these possible values would be allowed.
  Entities with possible values such as ``identification'' are discrete entities, while entities without possible values such as ``number of attempts'' are non discrete.

Next: Complex conditions Up: Conditions Previous: Conditions Contents

Stephane S. Some 2005-01-25