---
title: "Read YAML 1.1 files: yes, no and 0755"
url: https://recursiveai.org/oneyaml/rust/cookbook/yaml-1-1-booleans/
description: "Why oneyaml reads yes, no and 0755 the YAML 1.2 way in Rust, and how to read a YAML 1.1 file the old way with one setting or the Compat::yaml_1_1() preset."
version: "1.2.0"
---

# Read YAML 1.1 files: `yes`, `no` and `0755`

In YAML 1.1, `no` is `false` (the “Norway problem”) and `0755` is octal. YAML 1.2 fixed both: `no` is a string and `0755` is the decimal 755. oneyaml reads YAML 1.2 by default; when a file was written for an older parser, turn on the YAML 1.1 behaviors you need.

```rust
use oneyaml::{Compat, Settings, Value};

fn main() -> Result<(), oneyaml::Error> {
    let src = "\
country: no
enabled: yes
mode: 0755
";
    // YAML 1.2 (the default): `no` and `yes` are strings, 0755 is 755.
    let v: Value = oneyaml::from_str(src)?;
    println!("1.2: {:?} {:?} {:?}", v["country"], v["enabled"], v["mode"]);

    // One YAML 1.1 behavior at a time...
    let v: Value = oneyaml::from_str_with(src, &Settings::new().yaml11_booleans(true))?;
    println!("1.1 booleans: {:?} {:?}", v["country"], v["enabled"]);

    // ...or all of them, as older YAML 1.1 parsers read the file.
    let v: Value = oneyaml::from_str_with(src, &Compat::yaml_1_1())?;
    println!("1.1: {:?} {:?} {:?}", v["country"], v["enabled"], v["mode"]);
    Ok(())
}
```

```text
1.2: String("no") String("yes") Number(755)
1.1 booleans: Bool(false) Bool(true)
1.1: Bool(false) Bool(true) Number(493)
```

## Good to know

- Each YAML 1.1 behavior is its own setting, off by default: `yaml11_booleans`, `legacy_octal`, `sexagesimal`, `digit_separators`, `yaml11_int_forms` and `merge_keys`.
- `Compat::yaml_1_1()` turns them all on. `Compat::serde_yaml()` gets close to `serde_yaml`’s behavior, for a migration; the [migration guide](https://recursiveai.org/oneyaml/rust/docs/migrating-from-serde-yaml/) lists every difference.
- A boolean field given `yes` under YAML 1.2 is an error whose help suggests writing `true`, with a fix you can apply ([errors with line and column](https://recursiveai.org/oneyaml/rust/cookbook/errors-with-line-and-column/)).
- Quoted values are always strings: `"no"` is the string `no` under every setting.

Moving off serde_yaml: [serde_yaml is deprecated: what now](https://recursiveai.org/oneyaml/articles/serde-yaml-deprecated/).

Why NO becomes false, and what nine YAML libraries do with it: [The YAML Norway problem](https://recursiveai.org/oneyaml/articles/yaml-norway-problem/).