Current Limitations: Difference between revisions

Latest revision as of 12:53, 11 May 2023

ProB in general requires all deferred sets to be given a finite cardinality. If no cardinality is specified, a default size will be used. Also, unless finite bounds can be inferred by the ProB constraint solver, mathematical integers will only be enumerated within MININT to MAXINT (and ProB will generate enumeration warnings in case no solution is found).

Other general limitations are:

Trees and binary trees. These constructs are specific to the AtelierB tool and are only partially supported;

Definitions. Definitions (from the DEFINITIONS clause) with arguments are supported, but in contrast to AtelierB they are parsed independently and have to be either an expression, a predicate, or a substitution; definitions which are predicates or substitutions must be declared before first use. Also: the arguments of DEFINITIONS have to be expressions. Finally, when replacing DEFINITIONS the associativity is not changed. E.g., with PLUS(x,y) == x+y, the expression PLUS(2,3)*10 will evaluate to 50 (and not to 32 as with Atelier-B).

Also, ProB will generate a warning when variable capture may occur.

There are also limitations with refinements. See below;
VALUES This clause of IMPLEMENTATION machines is not yet fully supported;

Parsing: ProB will require parentheses around the comma, the relational composition, and parallel product operators. For example, you cannot write r2=rel;rel. You need to write r2=(rel;rel). This allows ProB to distinguish the relational composition from the sequential composition (or other uses of the semicolon). You also generally need to put BEGIN and END around the sequential composition operator, e.g., Op = BEGIN x:=1;y:=2 END.

See the page Using ProB with Atelier B for more details.

Multiple Machines and Refinements

It is possible to use multiple classical B machines with ProB. However, ProB may not enforce all of the classical B visibility rules (although we try to). As far as the visibility rules are concerned, it is thus a good idea to check the machines in another B tool, such as Atelier B or the B-Toolkit.

While refinements are supported, the preconditions of operations are not propagated down to refinement machines. This means that you should rewrite the preconditions of operations (and, if necessary, reformulate them in terms of the variables of the refinement machine). Also, the refinement checker does not yet check the gluing invariant.

Note however, that for Rodin Event-B models we now support multi-level animation and validation.

@@ Line 1: / Line 1: @@
-ProB requires all deferred sets to be given a finite cardinality. If no cardinality is specified a default size will be used. Also, mathematical integers will only be enumerated within MININT to MAXINT.
+[[Category:User Manual]]
+ProB in general requires all [[Deferred Sets|deferred sets]] to be given a finite cardinality. If no cardinality is specified, a default size will be used. Also, unless finite bounds can be inferred by the ProB constraint solver, mathematical integers will only be enumerated within <tt>MININT</tt> to <tt>MAXINT</tt>  (and ProB will generate enumeration
+warnings in case no solution is found).
 Other general limitations are:
-* closure The transitive and reflexive closure operator is not supported as defined in the B-Book by Abrial. AtelierB also does not support the operator as defined in the B-Book (as this version cannot be applied in practice). For the reflexive component of closure, ProB will compute the elements in the domain and range of the relation.
-Note, however, that the transitive closure operator closure1 is fully supported, and hence one can translate an expression closure(e), where e is a binary relation over some domain d, into the expression closure1(e) \/ id(d).
+* Trees and binary trees. These constructs are specific to the AtelierB tool and are only partially supported;
-* fnc, rel These operators are not supported. Also, succ and pred are only supported when applied to numbers (i.e., succ(x) is supported; dom(succ) is not).
+* Definitions. Definitions (from the <tt>DEFINITIONS</tt> clause) with arguments are supported, but in contrast to AtelierB they are parsed independently and have to be either an expression, a predicate, or a substitution; definitions which are predicates or substitutions must be declared before first use. Also: the arguments of <tt>DEFINITIONS</tt> have to be expressions. Finally, when replacing DEFINITIONS the associativity is not changed. E.g., with <tt>PLUS(x,y) == x+y</tt>, the expression <tt>PLUS(2,3)*10</tt> will evaluate to 50 (and not to 32 as with Atelier-B).
+Also, ProB will generate a warning when variable capture may occur.
-* Trees and binary trees. These onstructs are specific to AtelierB tool and are not supported (the STRING type is now supported);
+* There are also limitations with refinements. See below;
+* <tt>VALUES</tt> This clause of <tt>IMPLEMENTATION</tt> machines is not yet fully supported;
-* Definitions Definitions (from the DEFINITIONS clause) with arguments are now supported, but in contrast to AtelierB they are type-checked and have to be either and expression, a predicate or a substitution;
+* Parsing:  ProB will require parentheses around the comma, the relational composition, and parallel product operators. For example, you cannot write <tt>r2=rel;rel</tt>. You need to write <tt>r2=(rel;rel)</tt>. This allows ProB to distinguish the relational composition from the sequential composition (or other uses of the semicolon). You also generally need to put BEGIN and END around the sequential composition operator, e.g., <tt>Op = BEGIN x:=1;y:=2 END</tt>.
-** There are also limitations wrt refinements. See below;
-** VALUES This clause of IMPLEMENTATION machines is not yet supported;
+See the page [[Using ProB with Atelier B]] for more details.
 === Multiple Machines and Refinements ===
-It is possible to use multiple machines with ProB. However, ProB may not enforce all of the B visibility rules (although we try to). As far as the visibility rules are concerned, it is thus a good idea to check the machines in another B tool, such as Atelier B or the B-Toolkit.
+It is possible to use multiple classical B machines with ProB. However, ProB may not enforce all of the classical B visibility rules (although we try to). As far as the visibility rules are concerned, it is thus a good idea to check the machines in another B tool, such as Atelier B or the B-Toolkit.
+While refinements are supported, the preconditions of operations are not propagated down to refinement machines. This means that you should rewrite the preconditions of operations (and, if necessary, reformulate them in terms of the variables of the refinement machine). Also, the refinement checker does not yet check the gluing invariant.
-While refinements are supported, the preconditions of operations are not propagated down to refinement machines. This means that you should rewrite the preconditions of operations (and reformulate them in terms of the variables of the refinement machine, if necessary). Also, the refinement checker does yet check the gluing invariant;
+Note however, that for Rodin Event-B models we now support multi-level animation and validation.