### Use ResourceProxy to instantiate a FHIR model

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/Instantiation.md

This example demonstrates how to use ResourceProxy to dynamically instantiate FHIR models from JSON data. It shows how to get a generic Resource, a typed resource if available, and how to use pattern matching with the proxy.

```swift
import ModelsR4

let data = <FHIR JSON data>
let decoder = JSONDecoder()
do {
    let proxy = try decoder.decode(ResourceProxy.self, from: data)
    
    let resource = proxy.get()
    // `resource` is a generic `Resource`
    
    let patient = proxy.get(if: Patient.self)
    // `patient` is a nullable `Patient`
    
    if case .patient(let patient) = proxy {
        // `patient` is a `Patient`
    }
    
    switch proxy {
    case .patient(let patient):
        // `patient` is a `Patient`
        break
    default:
        break
    }
} catch {
    print("Failed to instantiate: \(error)")
}
```

--------------------------------

### Get resources from a FHIR Bundle

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/Instantiation.md

This example demonstrates how to parse a FHIR Bundle and extract specific resource types, such as Observations, from its entries.

```swift
import ModelsR4

let data = <FHIR JSON data>
let bundle = try JSONDecoder().decode(ModelsR4.Bundle.self, from: data)
let observations = bundle.entry?.compactMap {
    $0.resource?.get(if: ModelsR4.Observation.self)
}
// observations is an array of `Observation` instances
```

--------------------------------

### Working with Value-X

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/ModelProperties.md

Example of decoding a MedicationStatement and checking the type of the medication property (reference or codeableConcept).

```swift
let med = try decoder.decode(MedicationStatement.self, from: data)
if case .reference(let ref) = med.medication {
    print("--> medication reference display: \(ref.display ?? "{nil}")")
} else if case .codeableConcept(let cc) = med.medication {
    print("--> medication codeable concept text: \(cc.text ?? "{nil}")")
    // Note: you should also look at `cc.coding`
}
```

--------------------------------

### Example usage of the mothersFamilyName extension

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/Extensions.md

Demonstrates how to decode a FHIR Patient resource from a JSON string and use the `mothersFamilyName` extension to print the patient's family name and mother's family name.

```swift
import ModelsR4

let string = """
    {
        \"resourceType\": \"Patient\",
        \"id\": \"2429563849\",
        \"name\": [
            {
                \"use\": \"official\",
                \"family\": \"SMITH\",
                \"_family\": {
                    \"extension\": [
                        {
                            \"url\": \"http://hl7.org/fhir/StructureDefinition/humanname-mothers-family\",
                            \"valueString\": \"JOHNSON\"
                        }
                    ]
                },
                \"given\": [
                    \"JOHN\"
                ]
            }
        ]
    }
    """
guard let data = string.data(using: .utf8) else {
    throw ...
}

let decoder = JSONDecoder()
let patient = try decoder.decode(Patient.self, from: data)
for name in patient.name ?? [] {
    print("family: \(name.family?.value?.string ?? \"{nil}\"), mother's family: \(name.family?.mothersFamilyName ?? \"{nil}")")
}
// prints: "family: SMITH, mother's family: JOHNSON"
```

--------------------------------

### Working with Primitives - Getting String Value

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/ModelProperties.md

Shows how to extract the native Swift String value from a FHIRPrimitive<FHIRString>.

```swift
let id = resource.id?.value?.string
```

--------------------------------

### Decode to a known FHIR Resource type

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/Instantiation.md

This example shows how to directly decode JSON data into a specific FHIR resource type, like Patient, when the resource type is already known.

```swift
import ModelsR4

let data = <FHIR JSON data>
let decoder = JSONDecoder()
do {
    let resource = try decoder.decode(Patient.self, from: data)
} catch {
    print("Failed to instantiate Patient: \(error)")
}
```

--------------------------------

### Working with Primitives - Extension Method

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/ModelProperties.md

Shows how to use the asFHIR{type}Primitive() extension method on Swift native types like URL and String.

```swift
let url = URL(string: "http://apple.com")!.asFHIRURIPrimitive()
// url is a `FHIRPrimitive<FHIRURI>`
let str = "http://hl7.org/fhir".asFHIRURIPrimitive()
// str is a `FHIRPrimitive<FHIRURI>?`
```

--------------------------------

### Date Time Conversion

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/DateAndTime.md

Demonstrates parsing a date-time string into a DateTime object and accessing its components.

```swift
do {
    let dateTimeString = "2020-03-12T12:33:54.6543-06:00"
    let dateTime = try DateTime(dateTimeString)
    dateTime.date.year == 2020
    dateTime.time.minute == 33
    dateTime.timeZone == TimeZone(secondsFromGMT: -6 * 3600)
} catch {
    print("Failed to parse date time string: \(error)")
}
```

--------------------------------

### Working with Primitives - Direct Comparison

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/ModelProperties.md

Illustrates comparing a FHIRPrimitive<FHIRString> directly with a String literal.

```swift
if resource.id == "101" {
    
}
```

--------------------------------

### Package.swift dependency

Source: https://github.com/apple/fhirmodels/blob/main/README.md

How to add FHIRModels to your Package.swift file as a dependency.

```swift
dependencies: [
    .package(url: "https://github.com/apple/FHIRModels.git",
            .upToNextMajor(from: "0.9.1"))
]
```

--------------------------------

### Working with Primitives - Assignment

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/ModelProperties.md

Demonstrates assigning String and Bool literals to FHIR primitive properties.

```swift
let patient = Patient(...)
patient.id = "101"
patient.active = true
```

--------------------------------

### Patient with a Name

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/ModelProperties.md

Demonstrates instantiating a HumanName and Patient using ExpressibleByLiteral for primitive types.

```swift
import ModelsR4

let name = HumanName(family: "Altick", given: ["Kelly"])
let patient = Patient(name: [name])

name.given?.first                   // FHIRPrimitive<FHIRString>?
name.given?.first?.value            // FHIRString?
name.given?.first?.value?.string    // String?
```

--------------------------------

### Swift Extension for FHIRPrimitive to access mother's family name

Source: https://github.com/apple/fhirmodels/blob/main/HowTo/Extensions.md

This Swift extension adds a computed property `mothersFamilyName` to `FHIRPrimitive` to extract the mother's family name from a specific FHIR extension.

```swift
extension FHIRPrimitive {
    
    var mothersFamilyName: String? {
        guard let mothersFamilyExtension = extensions(for: "http://hl7.org/fhir/StructureDefinition/humanname-mothers-family").first else {
            return nil
        }
        if case .string(let str) = mothersFamilyExtension.value {
            return str.value?.string
        }
        // Not a `valueString`
        return nil
    }
}
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.