Rules
Syntax
- Rules
- empty
- Rules Rule
- Rule
- Rule
Label
RuleOptions
TbRule
Collage
Tablenumber
- RuleOptions
- empty
- Transforms RuleOptions
- RuleProb RuleOptions
- RuleProb
- empty
- Prob Num
- Tablenumber
- Table Num
- Global
Description
Defines the set of rules of a collage grammar. The set of rules
may have any number of elements, including zero. Each rule consists
of a label, a collage and an assigned table number.
- The label is
used to identify the hyperedges that are a possible target for the rule.
- The collage can replace matching hyperedges during the derivation
process if their pin-points can be transformed to the attach-points of
the hyperedge.
- The table number is used to control the derivation process.
Each rule is assigned to exactly one table or to all tables.
Options and alternative transformations can be specified to modify the
default behaviour of a rule. Rules with probalitities (0 to 1) can be
used to create non-deterministic derivations. Refer to the explanation of
the derivation process for details.
Example
Rule S Transformations ScaleTranslations
Pins 0,0 150,335.41 300,0
Edge A 0,0 50,111.8 100,0
Edge A 200,0 250,111.8 300,0
EndCollage
Table 1
This defines a rule labeled S. Its transformation class is restricted
to scalings and translations. The collage of the rule
(the socalled right-hand-side) has three pin-points and contains
two hyperedges both labeled A. As it contains no parts, replacing a
hyperedge with this rule has no visual effect per se. However, in the
next derivation step, a visual outcome depends on what rules exist for the
A-hyperedges.