Ad/2010-08-01 Concrete Syntax for a uml action Language for Foundational uml (Alf) Second Revised Submission
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ParserThe syntax grammar given below is an LL grammar, that is, a grammar designed for “top down” parsing (such as recursive descent). A lookahead of only one token is required for most of the grammar. In all other cases except one, a maximum lookahead of three tokens is required. The parsing of qualified names with template bindings, however, requires a potentially unbounded lookahead to distinguish the use of a “<” as an opening bracket of a template binding from its use as a less-than sign. As discussed in Subclause 8.2, the parsing of a syntactic element with the form of a qualified name using the dot notation may be ambiguous. In such cases, the grammar below always parses the potentially ambiguous element as a qualified name (using the non-terminal “PotentiallyAmbiguousQualifiedName”. If such an element is later disambiguated as a feature reference, this will also generally require reparsing of the expression containing the ambiguous qualified name (e.g., a name expression becomes a property access expression and a behavior invocation becomes a feature invocation). Finally, the LL form of the grammar given here is considerably simplified by allowing any unary expression as the left-hand side of an assignment and any primary expression as the operand of an increment or decrement expression, even though the required form for a left-hand side is actually more restrictive (see Subclause 8.8). This requires that the left-hand side of an assignment and the operand of an increment or decrement expression be checked after parsing to ensure that it has the form of a name expression, a property access expression or a sequence access expression whose primary expression is a name expression or a property access expression. Note that a similar static check needs to be performed anyway on the argument expressions for inout parameters (see Subclause 8.3.8).
/*************** * NAMES * ***************/ Name = QualifiedName = UnqualifiedName ( ColonQualifiedNameCompletion | DotQualifiedNameCompletion )? PotentiallyAmbiguousQualifiedName = UnqualifiedName ( ColonQualifiedNameCompletion | DotQualifiedNameCompletion /* AMBIGUOUS */ )? ColonQualifiedName = UnqualifiedName ColonQualifiedNameCompletion ColonQualifiedNameCompletion = ( DotQualifiedName = UnqualifiedName DotQualifiedNameCompletion DotQualifiedNameCompletion = ( UnqualifiedName = NameBinding NameBinding = Name ( TemplateBinding )?
TemplateBinding = | PositionalTemplateBinding ) PositionalTemplateBinding = QualifiedName ( NamedTemplateBinding = TemplateParameterSubstitution
TemplateParameterSubstitution = Name /*************** * EXPRESSIONS * ***************/ Expression = UnaryExpression ExpressionCompletion NonNameExpression = NonNameUnaryExpression ExpressionCompletion NameToExpressionCompletion = ( NameToPrimaryExpression )? PrimaryToExpressionCompletion PrimaryToExpressionCompletion = PostfixExpressionCompletion ExpressionCompletion ExpressionCompletion = AssignmentExpressionCompletion | ConditionalExpressionCompletion /* PRIMARY EXPRESSIONS */ PrimaryExpression = ( NameOrPrimaryExpression
BaseExpression = LiteralExpression | ThisExpression | SuperInvocationExpression | InstanceCreationOrSequenceConstructionExpression | SequenceAnyExpression NameToPrimaryExpression = | ClassExtentExpressionCompletion ) | SequenceConstructionExpressionCompletion | BehaviorInvocation PrimaryExpressionCompletion = ( Feature ( FeatureInvocation )? | SequenceOperationOrReductionOrExpansion | Index )* /* LITERAL EXPRESSIONS */ LiteralExpression = /* NAME EXPRESSIONS */ NameOrPrimaryExpression = PotentiallyAmbiguousQualifiedName
/* THIS EXPRESSIONS */ ThisExpression = /* PARENTHESIZED EXPRESSIONS */ ParenthesizedExpression = /* PROPERTY ACCESS EXPRESSIONS */ Feature = /* INVOCATION EXPRESSIONS */ Tuple = PositionalTupleExpressionList = Expression PositionalTupleExpressionListCompletion PositionalTupleExpressionListCompletion = ( NamedTupleExpressionList = NamedExpression ( NamedExpression = Name BehaviorInvocation = Tuple FeatureInvocation = Tuple SuperInvocationExpression = /* INSTANCE CREATION EXPRESSIONS */ InstanceCreationOrSequenceConstructionExpression = ( SequenceConstructionExpressionCompletion | Tuple ) /* LINK OPERATION EXPRESSIONS */ LinkOperationCompletion = LinkOperation LinkOperationTuple LinkOperation = | | LinkOperationTuple = ( Name ( Index ( IndexedNamedExpressionListCompletion | PrimaryToExpressionCompletion PositionalTupleExpressionListCompletion ) | IndexedNamedExpressionListCompletion ) | PositionalTupleExpressionList )? IndexedNamedExpressionListCompletion = Expression ( IndexedNamedExpression = Name ( Index )? /* CLASS EXTENT EXPRESSIONS */ ClassExtentExpressionCompletion = /* SEQUENCE CONSTRUCTION EXPRESSIONS */ SequenceAnyExpression = SequenceConstructionExpressionCompletion = ( MultiplicityIndicator )? ( SequenceElements )? MultiplicityIndicator = SequenceElements = Expression ( SequenceElementListCompletion = ( SequenceElement = Expression
SequenceInitializationExpression = ( /* SEQUENCE ACCESS EXPRESSIONS */ Index = /* SEQUENCE OPERATION, REDUCTION AND EXPANSION EXPRESSIONS */ SequenceOperationOrReductionOrExpansion
/* INCREMENT OR DECREMENT EXPRESSIONS */ PostfixExpressionCompletion = PrimaryExpressionCompletion
PostfixOperation = AffixOperator PrefixExpression = AffixOperator PrimaryExpression AffixOperator = ( /* UNARY EXPRESSIONS */ UnaryExpression = PostfixOrCastExpression | NonPostfixNonCastUnaryExpression PostfixOrCastExpression = NonNamePostfixOrCastExpression | NameOrPrimaryExpression PostfixExpressionCompletion NonNameUnaryExpression = NonNamePostfixOrCastExpression | NonPostfixNonCastUnaryExpression NonNamePostfixOrCastExpression = ( | PotentiallyAmbiguousQualifiedName ( | NameToExpressionCompletion PostfixExpressionCompletion ) | NonNameExpression PostfixExpressionCompletion ) | BaseExpression PostfixExpressionCompletion NonPostfixNonCastUnaryExpression = PrefixExpression | NumericUnaryExpression | BooleanNegationExpression | BitStringComplementExpression | IsolationExpression BooleanNegationExpression = BitStringComplementExpression = NumericUnaryExpression = NumericUnaryOperator UnaryExpression NumericUnaryOperator =
IsolationExpression = CastExpression = CastCompletion = PostfixOrCastExpression | BooleanNegationExpression | BitStringComplementExpression | IsolationExpression /* ARITHMETIC EXPRESSIONS */ MultiplicativeExpression = UnaryExpression
MultiplicativeExpressionCompletion = ( MultiplicativeOperator UnaryExpression )* MultiplicativeOperator = AdditiveExpression = UnaryExpression AdditiveExpressionCompletion AdditiveExpressionCompletion = MultiplicativeExpressionCompletion ( AdditiveOperator MultiplicativeExpression)* AdditiveOperator = ( | /* SHIFT EXPRESSIONS */ ShiftExpression = UnaryExpression ShiftExpressionCompletion ShiftExpressionCompletion = AdditiveExpressionCompletion ( ShiftOperator AdditiveExpression )* ShiftOperator = /* RELATIONAL EXPRESSIONS */ RelationalExpression = UnaryExpression RelationalExpressionCompletion RelationalExpressionCompletion = ShiftExpressionCompletion ( RelationalOperator ShiftExpression )? RelationalOperator = /* CLASSIFICATION EXPRESSIONS */ ClassificationExpression = UnaryExpression ClassificationExpressionCompletion ClassificationExpressionCompletion = RelationalExpressionCompletion ( ClassificationOperator QualifiedName )? ClassificationOperator = 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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