Appendix 1. Semantics of the micro KDM action elements

This appendix defines the semantics of micro KDM action elements. This section assumes understanding of the KDM Datatypes.

Each micro KDM action has the following 5 parts.

Action Kind, Inputs, Outputs, Control and Extras

Action Kind – is nature of the operation performed by the micro action. This is represented as a “kind” attribute to the micro action. The action kind may designate certain outgoing relationship as part of the Control. For example, the “call” micro action designated the Calls outgoing relationship as part of Control
Outputs – represented by the owned outgoing Writes relationship, which usually represents the result of the micro action. This part is optional.
Inputs – Ordered outgoing Reads and/or Addresses relationships that are owned by the action element, the order of the relationships represent the order of the arguments for a micro action.
Control part – owned outgoing control flow relationships for the action.
Extras part – owned relationships other than Reads, Writes and not designated as part of Control by the action Kind. For example, these can be interface compliance relation “CompliesTo” or any extended action relationships.

Comparison actions

Inputs: Two Reads relationships to DataElements representing values of the same datatype (except for Boolean NOT, which has a single Reads relationship).

Output: Optional writes to a DataElement of a Boolean type;

Control: Single flow – unconditional transfer of control to the next micro action (for example, as part of complex expressions);

**Comparison Actions**
Micro action	Semantics
Equals	Polymorphic equals for two values of the same datatype, see ISO Equals operation for the corresponding datatype
NotEqual	Polymorphic “not equal” for two values of the same datatype: not (A==B)
LessThanOrEqual	Polymorphic “less than or equal” for two values of the same ordered datatype; see ISO InOrder operation for the corresponding datatype
LessThan	Polymorphic “less than” for two values of the same ordered datatype: A<=B and not A==B
GreaterThan	Polymorphic “greater than or equal” for two values of the same ordered datatype: not A<=B
GreaterThanOrEqual	Polymorphic “less than or equal” for two values of the same ordered datatype: not A<=B or A==B
Not	Boolean NOT, see ISO Boolean NOT operation
And	Boolean AND, see ISO Boolean AND operation
Or	Boolean OR, see ISO Boolean OR operation
Xor	Boolean XOR: ( A and not B ) or (not A and B)

Actions related to the primitive numerical datatypes

Inputs: Two ordered Reads relationships to DataElements representing values of the same datatype (except for neg, succ, incr, decr unary operations, which have a single Reads relationship).

Output: Single Writes to a DataElement of a type corresponding to the definition of the operation (can be temporary register or a variable);

Control: Single flow – unconditional transfer of control to the next micro action.

**Numerical actions**
Micro action	Semantics
Add	Polymorphic add operation for a two values of the same numeric datatype, see ISO Add operation for the corresponding datatype
Multiply	Polymorphic multiply operation for two values of the same numeric datatype; see ISO Add operation for the corresponding datatype
Negate	Polymorphic unary negate operation for two values of the same numeric datatype; see ISO Negate operation for the corresponding datatype
Subtract	Polymorphic subtract operation for two values of the same numeric datatype; A+ neg B
Divide	Polymorphic divide operation for two values of the same numeric datatype
Remainder	Polymorphic remainder operation for two values of the same IntegerType datatype:
Successor	Single Reads; Successor for ordinal or enumerated types, see ISO Successor operation

Actions related to bitwise operations on primitive datatypes

Inputs: Two Reads relationships to DataElements representing values of the same datatype (except for neg, succ, incr, decr unary operations, which have a single Reads relationship).

Output: Single Writes to a DataElement of the same type as the first StorableElement (can be temporary register or a variable);

Control: Single Flow – unconditional transfer of control.

**Bitwise actions**
Micro action	Semantics	Inputs
BitAnd	Bitwise AND on two integers or bitstrings or octetstrings	Two Reads relationships to DataElements representing values of the same datatype
BitOr	Bitwise OR on two integers or bitstrings or octetstrings	Two Reads relationships to DataElements representing values of the same datatype
BitNot	Bitwise NOT on integer or bitstring or octetstring	Two Reads relationships to DataElements representing values of the same datatype
BitXor	Bitwise XOR on two integers or bitstrings or octetstrings	Two Reads relationships to DataElements representing values of the same datatype
LeftShift	Arithmetic bitwise shift left on integer or bitstring or octetsting	First Reads relationship to a DataElement representing an integer, bitstring or octetstring Second Reads relationship to an integer or ordinal representing the number of bits to shift
RightShift	Arithmetic bitwise shift right on integer or bitstring or octetstring	First Reads relationship to a DataElement representing an integer, bitstring or octetstring Second Reads relationship to an integer or ordinal representing the number of bits to shift
BitRightShift	Logical bitwise shift right on integer or bitstring or octetstring	First Reads relationship to a DataElement representing an integer, bitstring or octetstring Second Reads relationship to an integer or ordinal representing the number of bits to shift

Control actions

**Control actions**
Micro action	Description	Inputs	Outputs	Control
Assign	Assignment (copy)	Single Reads relationship to a DataElement representing the value	Writes relationship represents the DataElement (except for a ValueElement) to which the value of the input DataElement is assigned	Single flow to the next micro action
Condition	Condition	Single Reads relationship to a DataElement representing the Boolean value		TrueFlow & FalseFlow – conditional transfer of control
Call	Static call	Zero or more Reads relationships to DataElements, that represent input actual parameters; ordered; Value of each actual parameter is assigned to the corresponding formal parameter of the ControlElement. Correspondence is established according to the Pos attribute of the formal parameter in the signature of the ControlElement. A sequence of values is assigned to the variable argument.	Optional Writes to the DataElement that represents the return value	Calls relationship to the ControlElement represents the flow of control to the ControlElement and the return back; Subsequently a single flow to the next micro action is performed.
MethodCall	Method call	Invokes relationship to the DataElement that represents the instance; Zero or more Reads relationships to DataElements, that represent input actual parameters; ordered;	Same as Call	Calls relationship to the MethodUnit represents the flow of control to the Method and the return back; Subsequently a single flow to the next micro action is performed.
PtrCall	Call via pointer	Addresses relationship to the DataElement that represents the pointer; Zero or more Reads relationships to DataElements, that represent input actual parameters; ordered;	Same as Call	This represents a dynamic call to one of the possible targets of the pointer (corresponding to the current value of the pointer). The Signature of the possible targets is represented as the type attribute of the DataElement
VirtualCall	Virtual method call	Invokes relationship to the DataElement that represents the instance; Zero or more Reads relationships to DataElements, that represent input actual parameters; ordered;	Same as Call	Calls relationship to the MethodUnit represents the superclass of the method that will be determined dynamically. This represents the flow of control to the Method and the return back; Subsequently a single flow to the next micro action is performed.
Return	return	Single Reads represents the DataElement that contains the return value		Control is returned back to one of the ControlElements that has performed the call.
Nop	dummy	none	none	Single flow to the next micro action
Goto	Unconditional transfer of control	none	none	Single flow to the next micro action
Throw	Raising exception	zero or more Reads relationships to DataElements representing actual parameters to the exception being thrown	none	Throws relationship to the datatype that represents the “exception object”. Optional ExceptionFlow relationship to a CatchUnit that processes the exception
Incr	Variable post increment operation;	Single Addresses relationship represents the DataElement whose value is incremented;	Optional Writes relationship to another DataUnit to which the previous value of the incremented variable is assigned	Single flow to the next micro action
Decr	Variable post decrement operation;	Single Addresses relationship represents the DataElement whose value is decremented	Optional Writes relationship to another DataUnit to which the previous value of the incremented variable is assigned	Single flow to the next micro action
Switch	Branching based on the value of a StorableElement	Single Reads to the DataElement that represents the selector value	none	One or more GuardedFlow relations to a second micro action with a single Reads relationship that represents the guard value. A single FalseFlow represents the default branch. This construct represents selection of a single branch for which the value of the selector is equal to the value of the guard or the default branch
Compound	Compound action	none	none	Single Flow – the entry flow to the first internal action element

Actions related to access to datatypes

**Access actions**
Micro action	Description	Inputs	Outputs	Control
FieldSelect	Access to a particular ItemUnit of a RecordType	Single Addresses relationship to a DataElement (of a RecordType); Single Reads relationship to an ItemUnit representing the field being accessed	Writes relationship represents the DataElement (except for a ValueElement) to which the value of the field is assigned	Single flow to the next micro action
FieldReplace	Modification of a particular field of a RecordType	Single Addresses relationship to a DataElement (of a RecordType); Single Reads to a DataElement representing the new value	Writes relationship to an ItemUnit representing the field being modified;	Single flow to the next micro action
ChoiceSelect	Access to a particular ItemUnit of a ChoiceType	Single Addresses relationship to a DataElement (of a ChoiceType); Single Reads relationship to an ItemUnit representing the field type being accessed	Writes relationship represents the DataElement (except for a ValueElement) to which the value of the field is assigned	Single flow to the next micro action
ChoiceReplace	Modification of a particular field of a ChoiceType	Single Addresses relationship to a DataElement (of a ChoiceType); Single Reads to a DataElement representing the new value	Writes relationship to an ItemUnit representing the field being modified;	Single flow to the next micro action
Ptr	Access to a pointer to a StorableElement	Single Addresses relationship to a DataElement	Writes relationship to the StorableElement which will hold the new value	Single flow to the next micro action
PtrSelect	Access to a value via pointer	Single Addresses relationship to a DataElement (of an PointerType); Single Reads relationship to an ItemUnit of that PointerType representing the ItemUnit being accessed;	Writes relationship to the ItemUnit of that PointerType	Single flow to the next micro action
PtrReplace	Modification of an ItemUnit of a PointerType	Single Addresses relationship to a DataElement (of an PointerType); Last Reads to a DataElement representing the new value	Writes relationship to the ItemUnit of that PointerType	Single flow to the next micro action
ArraySelect	Access to a particular ItemUnit of an ArrayType	Single Addresses relationship to a DataElement (of an ArrayType); Single Reads relationship to an ItemUnit representing the ItemUnit being accessed; Last Reads represents the Index	Writes relationship represents the DataElement (except for a ValueElement) to which the value of the ItemUnit is assigned	Single flow to the next micro action
ArrayReplace	Modification of a particular ItemUnit of an ArrayType	Single Addresses relationship to a DataElement (of an ArrayType); Reads that represents the Index; Last Reads to a DataElement representing the new value	Writes relationship to an ItemUnit representing the ItemUnit being modified;	Single flow to the next micro action
MemberSelect	Access to a particular MemberUnit of a ClassType	Invokes relationship to the DataElement that represents the instance.Single Reads relationship to an MemberUnit representing the member being accessed	Writes relationship represents the DataElement (except for a ValueElement) to which the value of the field is assigned	Single flow to the next micro action
MemberReplace	Modification of a particular member of a ClassType	Single Invokes relationship to a DataElement (of a ClassType) that represents the instance of the object being accessed.Single Reads to a DataElement representing the new value	Writes relationship to an MemberUnit representing the member being modified;	Single flow to the next micro action
New	Creation of a new dynamic instance of a datatype; this has to be done separately if required	Creates relationship to the Datatype being created	Writes relationship represents the DataElement (except for a ValueElement) to which the reference to the new dynamic element is assigned	Single flow to the next micro action; This micro operation does not invoke the constructor of the new object;
NewArray	Creation of a new dynamic instance of an ArrayType datatype	Creates relationship to the Datatype being created; Reads relation to the DataElement that represents the length of the new array	Writes relationship represents the DataElement (except for a ValueElement) to which the reference to the new dynamic element is assigned	Single flow to the next micro action;

Actions related to type conversions

**Type conversion actions**
Micro action	Description	Inputs	Outputs	Control
Sizeof	Determines the length of a StorableUnit	Reads represents the DataElement;	Optional writes to a DataElement	Single flow to the next micro action;
Instanceof	Performs dynamic type check if the data element is of a certain datatype	Reads represents the DataElement; UsesCode relation represents the datatype	Writes to a DataElement of a Boolean type;	Single flow – unconditional transfer of control to the next micro action (for example, as part of complex expressions, or condition);
DynCast	Performs a dynamic cast of a DataElement to a certain Datatype	Reads represents the DataElement; UsesCode relation represents the datatype	Writes to a DataElement	Single flow – unconditional transfer of control to the next micro action (for example, as part of complex expressions, or condition);
TypeCast	Performs a static type conversion of a DataElement to a certain Datatype	Reads represents the DataElement; UsesCode relation represents the datatype	Optional writes to a DataElement	Single flow to the next micro action;

Actions related to StringType operations

**StringType actions**
Micro action	Description	Inputs	Outputs	Control
IsEmpty	True is the string x is empty	First Reads represents x;	writes to a DataElement	Single flow – unconditional transfer of control to the next micro action (for example, as part of complex expressions, or condition);
Head	Produces the value of the first element in the string x	First Reads represents x;	writes to a DataElement	Single flow to the next micro action;
Tail	Produces sequence that results from deleting the first element in the string x	First Reads represents x;	writes to a DataElement	Single flow to the next micro action;
Empty	Produces and empty string	UsesType to the required type	writes to a DataElement	Single flow to the next micro action;
Append	Produces the sequence that is formed by adding a single value y to the end of the string x	First Reads represents x; Second represents y	writes to a DataElement	Single flow to the next micro action;

Note:”==” operation on ISO strings is defined as full comparison, this does not work in Java, which has shallow comparison of object references

Actions related to SetType operations

**SetType actions**
Micro action	Description	Inputs	Outputs	Control
IsIn	True is the value x is a member of the set y, else false	First Reads represents x; Second represents y	Writes to a DataElement	Single flow – unconditional transfer of control to the next micro action (for example, as part of complex expressions, or condition);
Subset	True if every member of x is a member of y	First Reads represents x; Second represents y	writes to a DataElement	Single flow to the next micro action;
Difference	Produces the set that consists of the values that are in x and not in y	First Reads represents x; Second represents y	writes to a DataElement	Single flow to the next micro action;
Union	Produces the set that consists of the values that are either in x or in y	First Reads represents x; Second represents y	writes to a DataElement	Single flow to the next micro action;
Intersection	Produces the set that consists of the values that are both in x and in y	First Reads represents x; Second represents y	writes to a DataElement	Single flow to the next micro action;
Select	Produces a value of the base type that is in the set x	First Reads represents x;	writes to a DataElement	Single flow to the next micro action;
IsEmpty	True is the set x is empty	First Reads represents x;	writes to a DataElement	Single flow – unconditional transfer of control to the next micro action (for example, as part of complex expressions, or condition);
Empty	Produces and empty set	UsesType to the required type	writes to a DataElement	Single flow to the next micro action;

Actions related to SequenceType operations

**SequenceType actions**
Micro action	Description	Inputs	Outputs	Control
IsEmpty	True is the sequence x is empty	First Reads represents x;	writes to a DataElement	Single flow – unconditional transfer of control to the next micro action (for example, as part of complex expressions, or condition);
Head	Produces the value of the first element in the sequence x	First Reads represents x;	writes to a DataElement	Single flow to the next micro action;
Tail	Produces sequence that results from deleting the first element in the sequence x	First Reads represents x;	writes to a DataElement	Single flow to the next micro action;
Empty	Produces and empty sequence	UsesType to the required type	writes to a DataElement	Single flow to the next micro action;
Append	Produces the sequence that is formed by adding a single value y to the end of the sequence x	First Reads represents x; Second represents y	writes to a DataElement	Single flow to the next micro action;

Actions related to BagType operations

**BagType actions**
Micro action	Description	Inputs	Outputs	Control
IsEmpty	True is the bag x is empty	First Reads represents x;	writes to a DataElement	Single flow – unconditional transfer of control to the next micro action (for example, as part of complex expressions, or condition);
Select	Produces a value of the base type that is in the bag x	First Reads represents x;	writes to a DataElement	Single flow to the next micro action;
Delete	Produces the bag that is formed by deleting one instance of value y from the bag x if any	First Reads represents x; Second represents y	writes to a DataElement	Single flow to the next micro action;
Empty	Produces and empty bag	UsesType to the required type	writes to a DataElement	Single flow to the next micro action;
Insert	Produces the bag that is formed by adding one instance of value y from the bag x	First Reads represents x; Second represents y	writes to a DataElement	Single flow to the next micro action;
Serialize	Produces the sequence in which each element is repeated as many time as it occurs in the bag x	First Reads represents x;	writes to a DataElement	Single flow to the next micro action;