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| |
| // |
| // W A R N I N G |
| // ------------- |
| // |
| // This file is not part of the Qt API. It exists purely as an |
| // implementation detail. This header file may change from version to |
| // version without notice, or even be removed. |
| // |
| // We mean it. |
| |
| #ifndef Patternist_TypeChecker_H |
| #define Patternist_TypeChecker_H |
| |
| #include <private/qstaticcontext_p.h> |
| #include <private/qexpression_p.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| namespace QPatternist |
| { |
| /** |
| * @short Contains functions that applies Function Conversion Rules and other |
| * kinds of compile-time type checking tasks. |
| * |
| * @ingroup Patternist_types |
| * @author Frans Englich <frans.englich@nokia.com> |
| */ |
| class TypeChecker |
| { |
| public: |
| enum Option |
| { |
| /** |
| * @short When set, the function conversion rules are applied. |
| * |
| * For instance, this is type promotion and conversions from @c |
| * xs:untypedAtomic to @c xs:date. This is done for function calls, |
| * but not when binding an expression to a variable. |
| */ |
| AutomaticallyConvert = 1, |
| |
| /** |
| * @short Whether the focus should be checked or not. |
| * |
| * Sometimes the focus is unknown at the time |
| * applyFunctionConversion() is called, and therefore it is |
| * of interest to post pone the check to later on. |
| */ |
| CheckFocus = 2, |
| |
| /** |
| * When applyFunctionConversion() is passed AutomaticallyConvert |
| * and promotion is required, such as from @c xs:integer to |
| * @c xs:float, there will be no conversion performed, with the |
| * assumption that the receiver will call Numeric::toFloat() or |
| * similar. |
| * |
| * However, when GeneratePromotion is set, code will be generated |
| * that performs this conversion regardless of what any receiver |
| * do. |
| * |
| * This is useful in the case where one Expression only pipes the |
| * result of another. The only known case of that as of this |
| * writing is when UserFunctionCallsite evaluates its body. |
| */ |
| GeneratePromotion |
| }; |
| typedef QFlags<Option> Options; |
| |
| /** |
| * @short Builds a pipeline of artificial AST nodes that ensures @p operand |
| * conforms to the type @p reqType by applying the Function |
| * Conversion Rules. |
| * |
| * This new Expression is returned, or, if no conversions were necessary, |
| * @p operand as it is. |
| * |
| * applyFunctionConversion() also performs various checks, such as if |
| * @p operand needs the focus and that the focus is defined in the |
| * @p context. These checks are largely guided by @p operand's |
| * Expression::properties(). |
| * |
| * @see <a href="http://www.w3.org/TR/xpath20/\#id-function-calls">XML Path |
| * Language (XPath) 2.0, 3.1.5 Function Calls</a>, more specifically the |
| * Function Conversion Rules |
| */ |
| static Expression::Ptr |
| applyFunctionConversion(const Expression::Ptr &operand, |
| const SequenceType::Ptr &reqType, |
| const StaticContext::Ptr &context, |
| const ReportContext::ErrorCode code = ReportContext::XPTY0004, |
| const Options = Options(AutomaticallyConvert | CheckFocus)); |
| private: |
| |
| static inline Expression::Ptr typeCheck(Expression *const op, |
| const StaticContext::Ptr &context, |
| const SequenceType::Ptr &reqType); |
| /** |
| * @short Implements the type checking and promotion part of the Function Conversion Rules. |
| */ |
| static Expression::Ptr verifyType(const Expression::Ptr &operand, |
| const SequenceType::Ptr &reqSeqType, |
| const StaticContext::Ptr &context, |
| const ReportContext::ErrorCode code, |
| const Options options); |
| |
| /** |
| * Determines whether type promotion is possible from one type to another. False |
| * is returned when a promotion is not possible or if a promotion is not needed(as when |
| * the types are identical), since that can be considered to not be type promotion. |
| * |
| * @returns @c true if @p fromType can be promoted to @p toType. |
| * @see <a href="http://www.w3.org/TR/xpath20/#promotion">XML Path Language |
| * (XPath) 2.0, B.1 Type Promotion</a> |
| */ |
| static bool promotionPossible(const ItemType::Ptr &fromType, |
| const ItemType::Ptr &toType, |
| const StaticContext::Ptr &context); |
| |
| /** |
| * @short Centralizes a message-string to reduce work for translators |
| * and increase consistency. |
| */ |
| static inline QString wrongType(const NamePool::Ptr &np, |
| const ItemType::Ptr &reqType, |
| const ItemType::Ptr &opType); |
| |
| /** |
| * No implementation is provided for this constructor. This class |
| * is not supposed to be instantiated. |
| */ |
| inline TypeChecker(); |
| |
| Q_DISABLE_COPY(TypeChecker) |
| }; |
| } |
| |
| QT_END_NAMESPACE |
| |
| #endif |