docs/development/languages/fidl/guides/compatibility/table_member_add.md

<!-- WARNING: This file is machine generated by //src/tests/fidl/source_compatibility/gen, do not edit. -->

Note: This document covers API impact only. For more details, see the
[ABI compatibility page](/docs/development/languages/fidl/guides/compatibility/README.md)

# Add a table member

## Overview

-|[init](#init)|[step 1](#step-1)|[step 2](#step-2)
---|---|---|---
fidl|[link](#fidl-init)|[link](#fidl-1)|
dart|[link](#dart-init)||[link](#dart-2)
go|[link](#go-init)||[link](#go-2)
hlcpp|[link](#hlcpp-init)||[link](#hlcpp-2)
llcpp|[link](#llcpp-init)||[link](#llcpp-2)
rust|[link](#rust-init)||[link](#rust-2)

## Initial State {#init}

### FIDL {#fidl-init}

```fidl
type Profile = table {
    1: timezone Timezone;
    2: temperature_unit TemperatureUnit;
};
```

### Dart {#dart-init}

```dart
void useTable(fidllib.Profile profile) {
  if (profile.timezone != null) {
    print('timezone: ${profile.timezone}');
  }
  if (profile.temperatureUnit != null) {
    print('preferred unit: ${profile.temperatureUnit}');
  }
  profile.$unknownData?.forEach((ordinal, data) {
    print('unknown ordinal $ordinal with bytes ${data.data}');
  });
}
```

### Go {#go-init}

```go
func useTable(profile lib.Profile) {
	if profile.HasTimezone() {
		fmt.Printf("timezone: %s", profile.GetTimezone())
	}
	if profile.HasTemperatureUnit() {
		fmt.Printf("preferred unit: %s", profile.GetTemperatureUnit())
	}
	for ord, data := range profile.GetUnknownData() {
		fmt.Printf("unknown ordinal %d with bytes %v", ord, data.Bytes)
	}
}

```

### HLCPP {#hlcpp-init}

```cpp
void use_table(const fidl_test::Profile& profile) {
  if (profile.has_timezone()) {
    printf("timezone: %s", profile.timezone().c_str());
  }
  if (profile.has_temperature_unit()) {
    printf("preferred unit: %s", profile.temperature_unit().c_str());
  }
  for (const auto& entry : profile.UnknownData()) {
    printf("unknown ordinal %lu", entry.first);
  }
}
```

### LLCPP {#llcpp-init}

```cpp
void use_table(const fidl_test::wire::Profile& profile) {
  if (profile.has_timezone()) {
    printf("timezone: %s", profile.timezone().data());
  }
  if (profile.has_temperature_unit()) {
    printf("preferred unit: %s", profile.temperature_unit().data());
  }
}
```

### Rust {#rust-init}

```rust
fn use_table(profile: &fidl_lib::Profile) {
    if let Some(tz) = &profile.timezone {
        println!("timezone: {:?}", tz);
    }
    if let Some(unit) = &profile.temperature_unit {
        println!("preferred unit: {:?}", unit);
    }
    if let Some(data) = &profile.unknown_data {
        for (ordinal, bytes) in data.iter() {
            println!("unknown ordinal {} with bytes {:?}", ordinal, bytes);
        }
    }
}
```

## Update FIDL Library {#step-1}

- Add the new member

```diff
  type Profile = table {
      1: timezone Timezone;
      2: temperature_unit TemperatureUnit;
+     3: dark_mode bool;
  };

```

## Update Source Code {#step-2}

### Dart {#dart-2}

- You can now use the new member

```diff
  void useTable(fidllib.Profile profile) {
    if (profile.timezone != null) {
      print('timezone: ${profile.timezone}');
    }
    if (profile.temperatureUnit != null) {
      print('preferred unit: ${profile.temperatureUnit}');
    }
+   if (profile.darkMode != null) {
+     print('dark mode on: ${profile.darkMode}');
+   }
    profile.$unknownData?.forEach((ordinal, data) {
      print('unknown ordinal $ordinal with bytes ${data.data}');
    });
  }

```

### Go {#go-2}

- You can now use the new member

```diff
  func useTable(profile lib.Profile) {
  	if profile.HasTimezone() {
  		fmt.Printf("timezone: %s", profile.GetTimezone())
  	}
  	if profile.HasTemperatureUnit() {
  		fmt.Printf("preferred unit: %s", profile.GetTemperatureUnit())
  	}
+ 	if profile.HasDarkMode() {
+ 		fmt.Printf("dark mode on: %t", profile.GetDarkMode())
+ 	}
  	for ord, data := range profile.GetUnknownData() {
  		fmt.Printf("unknown ordinal %d with bytes %v", ord, data.Bytes)
  	}
  }
  

```

### HLCPP {#hlcpp-2}

- You can now use the new member

```diff
  void use_table(const fidl_test::Profile& profile) {
    if (profile.has_timezone()) {
      printf("timezone: %s", profile.timezone().c_str());
    }
    if (profile.has_temperature_unit()) {
      printf("preferred unit: %s", profile.temperature_unit().c_str());
    }
+   if (profile.has_dark_mode()) {
+     printf("dark mode on: %s", profile.dark_mode() ? "true" : "false");
+   }
    for (const auto& entry : profile.UnknownData()) {
      printf("unknown ordinal %lu", entry.first);
    }
  }

```

### LLCPP {#llcpp-2}

- You can now use the new member

```diff
  void use_table(const fidl_test::wire::Profile& profile) {
    if (profile.has_timezone()) {
      printf("timezone: %s", profile.timezone().data());
    }
    if (profile.has_temperature_unit()) {
      printf("preferred unit: %s", profile.temperature_unit().data());
    }
+   if (profile.has_dark_mode()) {
+     printf("dark mode on: %s", profile.dark_mode() ? "true" : "false");
+   }
  }

```

### Rust {#rust-2}

- You can now use the new member

```diff
  fn use_table(profile: &fidl_lib::Profile) {
      if let Some(tz) = &profile.timezone {
          println!("timezone: {:?}", tz);
      }
      if let Some(unit) = &profile.temperature_unit {
          println!("preferred unit: {:?}", unit);
      }
+     if let Some(is_on) = &profile.dark_mode {
+         println!("dark mode on: {}", is_on);
+     }
      if let Some(data) = &profile.unknown_data {
          for (ordinal, bytes) in data.iter() {
              println!("unknown ordinal {} with bytes {:?}", ordinal, bytes);
          }
      }
  }

```