Navigation

The tree navigation module contains the object representations of the tree-navigation category FHIRPath functions.

Children

Bases: FHIRPathFunction

Representation of the FHIRPath children() function.

Source code in fhircraft/fhir/path/engine/navigation.py

class Children(FHIRPathFunction):
    """
    Representation of the FHIRPath [`children()`](https://hl7.org/fhirpath/N1/#children-collection) function.
    """        
    def evaluate(self, collection: List[FHIRPathCollectionItem], create: bool = False) -> List[FHIRPathCollectionItem]:
        """
        Returns a collection with all immediate child nodes of all items in the input collection.

        Args: 
            collection (List[FHIRPathCollectionItem])): The input collection.

        Returns:
            List[FHIRPathCollectionItem]): The collection of child items.
        """
        collection = ensure_list(collection)
        children_collection = []
        for item in collection:
            if isinstance(item.value, BaseModel):
                fields = item.value.model_fields
            elif isinstance(item.value, dict):
                fields = list(item.value.keys())
            else:
                fields = []
            for field in fields:
                children_collection.extend(
                    Element(field).evaluate(item, create)
                )
        return children_collection

evaluate(collection, create=False)

Returns a collection with all immediate child nodes of all items in the input collection.

Parameters:

Name	Type	Description	Default
collection	List[FHIRPathCollectionItem]	The input collection.	required

Returns:

Type	Description
List[FHIRPathCollectionItem]	List[FHIRPathCollectionItem]): The collection of child items.

Source code in fhircraft/fhir/path/engine/navigation.py

def evaluate(self, collection: List[FHIRPathCollectionItem], create: bool = False) -> List[FHIRPathCollectionItem]:
    """
    Returns a collection with all immediate child nodes of all items in the input collection.

    Args: 
        collection (List[FHIRPathCollectionItem])): The input collection.

    Returns:
        List[FHIRPathCollectionItem]): The collection of child items.
    """
    collection = ensure_list(collection)
    children_collection = []
    for item in collection:
        if isinstance(item.value, BaseModel):
            fields = item.value.model_fields
        elif isinstance(item.value, dict):
            fields = list(item.value.keys())
        else:
            fields = []
        for field in fields:
            children_collection.extend(
                Element(field).evaluate(item, create)
            )
    return children_collection

Descendants

Bases: FHIRPathFunction

Representation of the FHIRPath descendants() function.

Source code in fhircraft/fhir/path/engine/navigation.py

class Descendants(FHIRPathFunction):
    """
    Representation of the FHIRPath [`descendants()`](https://hl7.org/fhirpath/N1/#descendants-collection) function.
    """        
    def evaluate(self, collection: List[FHIRPathCollectionItem], create: bool = False) -> List[FHIRPathCollectionItem]:
        """
        Returns a collection with all descendant nodes of all items in the input collection. The result does not include
        the nodes in the input collection themselves. 

        Args: 
            collection (List[FHIRPathCollectionItem])): The input collection.

        Returns:
            List[FHIRPathCollectionItem]): The collection of descendant items.

        Note:
            This function is a shorthand for `repeat(children())`.
        """    
        return Repeat(Children()).evaluate(collection, create)

evaluate(collection, create=False)

Returns a collection with all descendant nodes of all items in the input collection. The result does not include the nodes in the input collection themselves.

Parameters:

Name	Type	Description	Default
collection	List[FHIRPathCollectionItem]	The input collection.	required

Returns:

Type	Description
List[FHIRPathCollectionItem]	List[FHIRPathCollectionItem]): The collection of descendant items.

Note

This function is a shorthand for repeat(children()).

Source code in fhircraft/fhir/path/engine/navigation.py

def evaluate(self, collection: List[FHIRPathCollectionItem], create: bool = False) -> List[FHIRPathCollectionItem]:
    """
    Returns a collection with all descendant nodes of all items in the input collection. The result does not include
    the nodes in the input collection themselves. 

    Args: 
        collection (List[FHIRPathCollectionItem])): The input collection.

    Returns:
        List[FHIRPathCollectionItem]): The collection of descendant items.

    Note:
        This function is a shorthand for `repeat(children())`.
    """    
    return Repeat(Children()).evaluate(collection, create)