- XML (Extensible Markup Language) Reader/Writer
- XML Quick Facts
- Workbench XML Reader Parameters
- Workbench XML Writer Parameters
- Feature Representation
- Mapping File Reference
- xfMap
- Reading the Input XML Document
- Mapping Rules
- Types of Mapping Rules
- Match and Except Expression
- Specifying Several Match Expressions for One Mapping Rule
- Limiting Mapping Rule Activation with Except Expressions
- Mapping Rule States (activation, execution, suspension, and de-activation)
- Using Force Elements During Mapping Rule Activation and Deactivation
- Search-sets
- Expression Elements (Extract and Literal)
- Expression Sequence
- Feature Mapping Rules
- FME Feature Construction
- Feature Type Element
- Attributes Element
- FME Feature Construction (defining mapping rules under the <feature-content-map> element)
- Attribute Element (handling multiple values)
- Attribute Element (handling optional attributes)
- Attribute Element (sequenced attributes)
- Attribute Element (Nillable Attributes)
- Geometry Element
- Geometry Builder States (activation, execution, suspension, and de-activation)
- Geometry Construction
- Composite Geometry Builders
- Built-in Geometry Builders
- xml-point
- xml-point-xy
- xml-line
- xml-area
- xml-donut
- xml-aggregate
- xml-box
- xml-text
- xml-path
- xml-arc
- xml-arc-by-center-point
- xml-elliptical-arc
- xml-circle
- xml-clothoid
- xml-polygon
- xml-face
- xml-composite-surface
- xml-triangulated-surface
- xml-enclosed-surface
- xml-composite-solid
- xml-multi-point
- xml-multi-curve
- xml-multi-area
- xml-multi-text
- xml-multi-surface
- xml-multi-solid
- xml-null
- xml-reverse-geometry
- xml-geodesic-string
- fme-geometry
- Mapping Segmented Geometric Information
- Geometry Traits (trait element)
- FME Feature Construction (constructing multiple features at a time)
- Structure Element
- References Element
- Apply References Element
- Group Mapping Rules
- Reference Mapping Rules
- Mapping Rules (Optional Elements)
- More Expression Elements
- FME Schema Features
- Reading the Input XML Document
refexpr Expressions
The refexpr expression allows access to stored reference values and is represented in the xfMap by the <refexpr> element.
The general syntax for the element is:
<refexpr expr=”...” default=”...” reference-group=”...” r-stack=”...”> <arg> ... optional reference name as expr seq ... </arg> <arg> ... optional default value as expr seq ... </arg> </refexpr>
The expr attribute denotes the name for a stored reference. The optional default attribute may contain the value returned by the expression in the case that a reference by that name is not found in any of the constructed reference-sets. This may occur if the reference was never stored or if the reference-set containing that reference was already destroyed.
Both <arg> child elements in the <refexpr> element are optional.
The expr attribute is required but it may be the empty string, in which case the first <arg> child element must be present, and the evaluated expression sequence for this first argument becomes the reference’s name to search.
If the default attribute is absent or if it is present but its value is the empty string, then the second argument, if present, is evaluated to become the default value for the expression in the case that the reference is not found.
The reference-group attribute is optional and it specifies the group-name for a reference in a reference-set. If the reference-group attribute is absent, then the default group in a reference-set is assumed.
The r-stack attribute is optional and it specifies the starting place to search for values in the stack of reference-sets. The valid values for the r-stack attribute are top, previous and bottom, with top being the default value.