From 5e527213a2430bb3018e5eebd909aef294edf9b5 Mon Sep 17 00:00:00 2001 From: Karen Arutyunov Date: Fri, 18 Dec 2020 18:48:46 +0300 Subject: Switch to build2 --- xsd-examples/cxx/tree/custom/double/README | 62 ++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 xsd-examples/cxx/tree/custom/double/README (limited to 'xsd-examples/cxx/tree/custom/double/README') diff --git a/xsd-examples/cxx/tree/custom/double/README b/xsd-examples/cxx/tree/custom/double/README new file mode 100644 index 0000000..15348d2 --- /dev/null +++ b/xsd-examples/cxx/tree/custom/double/README @@ -0,0 +1,62 @@ +This example shows how to customize parsing and serialization code for the +xsd:double XML Schema built-in type using the type customization mechanism +provided by the C++/Tree Mapping. For more information on type customization +see the C++/Tree Mapping Customization Guide, particularly sections 1 and 4: + +http://wiki.codesynthesis.com/Tree/Customization_guide + +In this example our schema uses xsd:double to represent a price. There are +two potential problems with this choice of a price type. First, xsd:double +can be serialized in the scientific notation which would be an unusual way +of representing a price. Second, we would like to limit the number of +fraction digits in our prices to 2. Furthermore, we would like to always +have two fraction digits, even if one or both of them are zeros, for +example: 12.99, 12.90, 12.00. + +In case we can modify the schema, a better approach would be to define the +price type as a restriction of the xsd:decimal type (always fixed notation) +and specify the fractionDigits facet to limit the number of fraction digits +to 2. However, there is no way in XML Schema to specify that there should +always be exactly 2 fraction digits. Therefore, it may still be desirable +to customize this price type to get the required serialization behavior. + +Finally, it is worth noting that the behavior achieved in this example via +type customization can also be achieved by compiling your code with the +following macros defined: + +XSD_TREE_DOUBLE_FIXED +XSD_TREE_DOUBLE_PRECISION 2 + +However, the type customization approach while requiring more work is +cleaner since it does not rely on global macro definitions. + +This example consists of the following files: + +order.xsd + XML Schema definition for a simple order vocabulary. + +double-custom.hxx +double-custom.cxx + Custom parsing and serialization code for the xsd:double types. The + double-custom.hxx file is included at the end of the xml-schema.hxx + file described below. + +xml-schema.hxx + C++ types for XML Schema built-in types. This header file is generated + by the XSD compiler using the --generate-xml-schema option. The + --custom-type option is used to customize the xsd:double type. The + --hxx-epilogue option is used to include the double-custom.hxx file + at the end of this file. + +order.hxx +order.cxx + C++ types generated from order.xsd. The --extern-xml-schema option + is used to include xml-schema.hxx into order.hxx. + +driver.cxx + Test driver for the example. It creates a sample order and then + writes it to XML to test the custom xsd:double serialization code. + +To run the example simply execute: + +$ ./driver -- cgit v1.1