Ad/2010-08-01 Concrete Syntax for a uml action Language for Foundational uml (Alf) Second Revised Submission
Increment and Decrement Expressions
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- 8.5Unary Expressions
- 8.5.2Boolean Unary Expressions
- 8.5.3BitString Unary Expressions
- 8.5.4Numeric Unary Expressions
- 8.5.5Cast Expressions
- 8.5.6Isolation Expressions
8.4Increment and Decrement ExpressionsAn increment expression is one that uses the increment operator ++. A decrement expression is one that uses the decrement operator --. Either of these operators may be used in either a prefix form, in which the operator appears before the the operand expression, or a postfix form, in which the operator appears after the operand expression. Examples Postfix Form count++ size--
total[i]++ Prefix Form ++count --numberWaiting[queueIndex] Syntax IncrementOrDecrementExpression(e: IncrementOrDecrementExpression) = PostfixExpression(e) | PrefixExpression(e) (e.isPrefix=true) PostfixExpression(e: IncrementOrDecrementExpression) = LeftHandSide(e.operand) AffixOperator(e.operator) PrefixExpression(e: IncrementOrDecrementExpression) = AffixOperator(e.operator) LeftHandSide(e.operand) AffixOperator(op: String) = "++"(op) | "--"(op) 
Figure 8 25 Increment and Decrement Expressions Cross References
Semantics The operand expression for an increment or decrement expression must conform to the syntax and static semantics for the left hand side of an assignment (see Subclause 8.8). It must have type Integer and multiplicity upper bound of 1. The increment or decrement expression has type Integer, the same multiplicity lower bound as its operand expression and a multiplicity upper bound of 1. The effect of an increment or decrement expression is to increment (++) or decrement (--) the value of its operand and then reassigns the result to the operand. If the operator is used as a postfix, then the value of the expression is the value of its operand before it is reassigned. If the operator is used as a prefix, the value of the expression is the values of its operand after it is reassigned. For example, if the local name a has the value 5, then both a++ and ++a assign the value 6 to a. However the value of the expression a++ itself is 5, while the value of ++a is 6. 8.5Unary Expressions8.5.1OverviewA unary expression is an expression with a single operand expression and an operator that performs some action on the values produced by the operand. Unary operators include numeric unary operators, Boolean negation and isolation. Cast expressions, which filter a sequence of values based on type, are also considered unary expressions in terms of concrete syntax, even though their “operator” is given by a type name, not a fixed symbol. The static and execution semantics of each kind of unary expression are discussed further in subsequent subclauses. Syntax UnaryExpression(e: Expression) = PrimaryExpression(e) | IncrementOrDecrementExpression(e) | BooleanUnaryExpression(e) | BitStringUnaryExpression(e) | NumericUnaryExpression(e) | CastExpression(e) | IsolationExpression(e) 
Figure 8 26 Base Abstract Syntax for Unary Expressions Cross References
8.5.2Boolean Unary ExpressionsA Boolean unary expression is a unary expression whose operator acts on and produces Boolean values. The only Boolean unary operator is the negation operator !. Examples !isActive !this.running
Figure 8 27 Abstract Syntax of Boolean Unary Expressions Cross References
Semantics A Boolean unary expression must have an operand expression with type Boolean and a multiplicity upper bound of 1. The Boolean unary expression has type Boolean, the same multiplicity lower bound as its operand expression and a multiplicity upper bound of 1. The functionality of the Boolean negation operator is the same as an application of the Alf library BooleanFunctions::'!' function (see Subclause 11.3.1) with the operand expression as its argument. If the operand is true, the result is false. If the operand is false, the result is true.
~registerContext ~memory.getByte(address)
Figure 8 28 Abstract Syntax of BitString Unary Expressions Semantics A BitString unary expression must have an operand expression with type BitString or Integer and a multiplicity upper bound of 1. The BitString unary expression has type BitString, the same multiplicity lower bound as its operand expression and a multiplicity upper bound of 1. If the operand is an integer, then it is first converted to a bit string by applying the library BitStringFunctions::ToBitString function (see Subclause 11.3.5). The functionality of the BitString bit-wise complement operator is the same as an application of the Alf library BitStringFunctions::'~' function (see Subclause 11.3.5) with the operand expression as its argument. The result is a bit string that has a bit set (value 1) in each bit position in which the operand bit string had its bit unset (value 0) and a bit unset (value 0) in each bit position in which the operand bit string had its bit set (value 1).
+1234
-42 +(a*b)
-absoluteValue Syntax NumericUnaryExpression(e: NumericUnaryExpression) = NumericUnaryOperator(e.operator) UnaryExpression(e.operand) NumericUnaryOperator(op: String) = "+"(op) | "-"(op) 
Figure 8 29 Abstract Syntax of Numeric Unary Expressions Cross References
Semantics A numeric unary expression must have an operand expression with type Integer and a multiplicity upper bound of 1. A numeric unary expression has type Integer, the same multiplicity lower bound as its operand expression and a multiplicity upper bound of 1. The unary plus operator does not change its operand value, while the unary minus operator negates it. The unary minus operator has the same functionality as application of the Alf library IntegerFunctions::Neg function (see Subclause 11.3.2), with the operand expression as the argument.
(fUML::Syntax::Activity)this.getTypes() (Person)invoice.payingParty (any)this Syntax CastExpression(e: CastExpression) = "(" TypeName(e.typeName) ")" NonNumericUnaryExpression(e.operand) NonNumericUnaryExpression(e: Expression) = PrimaryExpression(e) | PostfixExpression(e) | BooleanUnaryExpression(e) | BitStringUnaryExpression(e) | CastExpression(e) | IsolationExpression(e) 
Figure 8 30 Abstract Syntax of Cast Expressions Cross References
Semantics Unless the type name in a cast expression is the keyword any, the cast expression has the given type (see also Subclause 8.2 on type names). If the type name is any, then the cast expression is untyped. If the type name is a qualified name, then it must resolve to a classifier, which must not be a template, though it may be a binding of a template classifier. A cast expression is evaluated by first evaluating its operand expression, producing a sequence of values. Any values of the operand expression whose dynamic type does not conform to the type of the cast expression are filtered out, so that all result values of the cast expression are of the given type. If the cast expression is untyped, then no values are filtered out. For example, the cast expression (Integer)any[]{1,"banana",2} evaluates to Integer[]{1,2}
The multiplicity lower bound of a cast expression is 0 and the upper bound is the same as that of the operand expression. 8.5.6Isolation ExpressionsAn isolation expression is a unary expression with the isolation operator $. NOTE. The isolation expression notation is not available at the minimum conformance level (see Subclause 2.1). Examples $this.monitor.getActiveSensor().getReading() Syntax IsolationExpression(e: IsolationExpression) = "$"(e.operator) UnaryExpression(e.operand) 
Figure 8 31 Abstract Syntax of Isolation Expressoins Cross References
Semantics The isolation operator indicates that its operand expression should be evaluated in isolation, similarly to the use of the @isolated annotation for a statement (see Subclause 9.2). That is, during the evaluation of the operand expression, no object accessed as part of the evaluation of the expression or as the result of a synchronous invocation from the expression may be modified by any action that is not executed as part of the operand expression or as the result of a synchronous invocation from that expression. NOTE. See Subclause 8.5.3.1 of the fUML Specification for a complete discussion of the semantics of isolation. An isolation expression has the type and multiplicity of its operand expression. Directory: spec spec -> Illinois state board of education spec -> Volume Ⅴ (2015) On The 2015 China Victory Day Parade spec -> General information spec -> Topeka capital-journal spec -> P-8153 Frederick Tilp II (upper right) with plumbers who worked for him spec -> Catalog of My Wine Library Thomas Pinney Claremont, California 2004 note spec -> Unique 00225 Mobile Barrier (2015 Specifications: 12-04-14) spec -> Annual Conference " Initium Novum" spec -> Petroleum Development Oman L. L. C. Document Title: Specification for hse cases Download 1.74 Mb. Share with your friends:
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