WikiPrint - from Polar Technologies

This page describes currently proposed language for meta-descriptions. It may be updated frequently.

Operators

Relational operators

Standard relational operators apply

Meaning Operator
Less than <
Less or equal <=
Greater than >
Greater or equal>=
Equal =
Different than !=

Logical operators

Standard logical operators apply

Meaning Operator
And and
Or or
Xor xor
Not not

For events in the timeline of events, using and or or operators denotes that any ordering between these events is possible.

Arithmetic operators

Standard arithmetic operators apply and parenthesis are used for non-obvious precedence

Temporal operators

We want to be able to denote order and concurrency of events and state changes, and duration of events.

Meaning Operator and example
A occurs after B B -> A
A and B occur concurrently A | | B
A lasts T time AT
A occurs T time after B B ->T A

Existential, cardinality and modal operators

We want to be able to denote how many objects or events of a given type must/may occur.

Meaning Operator and example
Every object A each A
Some objects A some A
Some object A called a1 some A a1
A must occur A
A may occur [A]
Exactly N objects/events of type A |A|N
At least N objects/events of type A |A|>=N
At most N objects/events of type A |A|<=N

Conditions and loops

We want to be able to express that an event occurs under certain conditions.

MeaningOperator and example
if condition cond holds then A occurs else B occurs if cond then A else B
Repeat some action while condition cond holds do A while cond

Objects

An object has a type, may have certain variables associated with it, and an initial state. Logical topology describes (each item is in separate section):

Meaning Operator and example
A is of type X A extends X
A’s initial state is Z A := { state = Z}
A has an object M of type Y and with initial value I A := { Y M = I}
A is an alias for B in state C B := A{ state = C}
There are N objects of type A |A|N
A is different than B A != B
A and B reside on the same physical node collocated(A,B)

States and state changes

State name may be just a symbolic name or it may be associated with an object variable holding some value. An object in a given state always responds in the same manner to the same stimuli.

State change names start with s followed by a number. They are defined within curly brackets by specifying the object and its new state, like this:

s1 := {object.state = newstate}

Events

Some events may lead to transitions between states, others occur but don’t change object state. Each event has the type, the origin and one or more destinations. These are specified within curly brackets. Event names start with e followed by a number. Each event may have multiple parameters. Example of an event definition:

e1 := {type = TYPE, origin = object, destination = object, …}