Struct Config 

pub struct Config {
    pub value: Value,
    pub explicit_braces: bool,
}

A libconfig document that tracks top-level formatting.

Config wraps a Value and remembers whether the outer group uses implicit format (no braces) or explicit format ({...}).

Create an empty config with Config::new, parse from a string with Config::from_str, or wrap an existing Value with Config::from(value).

Config derefs to Value, so all Value methods (indexing, lookup, set, remove) work directly on a Config.

Examples

use libconfig::{Config, Value};

let mut config = Config::new();
config.set("name", Value::String("test".into()));
config.set("version", Value::Integer(42));

assert_eq!(config["name"], "test");
assert_eq!(config["version"], 42);

let output = config.to_string().unwrap();
assert_eq!(output, "name = \"test\";\nversion = 42;");

Fields

value: Value

The root value of the configuration

explicit_braces: bool

Whether the outer group has explicit braces

Implementations

impl Config

pub fn new() -> Self

Create a new empty Config with implicit outer group format.

pub fn from_str(s: &str) -> Result<Config>

Parse a libconfig string into a Config, automatically detecting whether the input uses an implicit group (no outer braces) or explicit group ({...}).

Examples

use libconfig::Config;

// Implicit group (no braces)
let config = Config::from_str("a = 1; b = 2;").unwrap();
assert!(!config.explicit_braces);
assert_eq!(config["a"], 1);

// Explicit group (with braces)
let config = Config::from_str("{ a = 1; b = 2; }").unwrap();
assert!(config.explicit_braces);
assert_eq!(config["a"], 1);

pub fn from_file<P: AsRef<Path>>(path: P) -> Result<Config>

Read and parse a libconfig file into a Config, automatically detecting whether the input uses an implicit or explicit group.

Examples

use libconfig::Config;

let config = Config::from_file("settings.cfg").unwrap();
println!("{}", config["name"]);

pub fn to_string(&self) -> Result<String>

Serialize this config to a libconfig string, respecting the explicit_braces setting.

Methods from Deref<Target = Value>

pub fn is_bool(&self) -> bool

Returns true if the value is a boolean

pub fn is_integer(&self) -> bool

Returns true if the value is an integer (32-bit or 64-bit)

pub fn is_i32(&self) -> bool

Returns true if the value is a 32-bit integer

pub fn is_i64(&self) -> bool

Returns true if the value is a 64-bit integer

pub fn is_float(&self) -> bool

Returns true if the value is a float

pub fn is_number(&self) -> bool

Returns true if the value is a number (integer or float)

pub fn is_string(&self) -> bool

Returns true if the value is a string

pub fn is_array(&self) -> bool

Returns true if the value is an array

pub fn is_list(&self) -> bool

Returns true if the value is a list

pub fn is_group(&self) -> bool

Returns true if the value is a group (object)

pub fn as_bool(&self) -> Option<bool>

If the value is a boolean, returns it. Returns None otherwise.

pub fn as_i32(&self) -> Option<i32>

If the value is an integer, returns it as i32. Returns None otherwise.

pub fn as_i64(&self) -> Option<i64>

If the value is an integer, returns it as i64. Returns None otherwise.

pub fn as_f64(&self) -> Option<f64>

If the value is a float, returns it. Returns None otherwise.

pub fn as_str(&self) -> Option<&str>

If the value is a string, returns a reference to it. Returns None otherwise.

pub fn as_array(&self) -> Option<&Vec<Value>>

If the value is an array or list, returns a reference to it. Returns None otherwise.

pub fn as_group(&self) -> Option<&Map>

If the value is a group, returns a reference to the map. Returns None otherwise.

pub fn get<S: AsRef<str>>(&self, key: S) -> Option<&Value>

Gets a reference to a value in a group by key

Returns None if the value is not a group or the key doesn’t exist.

pub fn get_mut<S: AsRef<str>>(&mut self, key: S) -> Option<&mut Value>

Gets a mutable reference to a value in a group by key

Returns None if the value is not a group or the key doesn’t exist.

pub fn get_index(&self, index: usize) -> Option<&Value>

Gets a reference to a value in an array/list by index

Returns None if the value is not an array/list or the index is out of bounds.

pub fn lookup(&self, path: &str) -> Option<&Value>

Looks up a value by a dotted path like “application.window.title”

Returns None if any part of the path doesn’t exist.

Examples

use libconfig::Value;

let config = r#"
    {
        application = {
            window = {
                title = "My App";
            };
        };
    }
"#;

let v = Value::from_str(config).unwrap();
assert_eq!(v.lookup("application.window.title").and_then(|v| v.as_str()), Some("My App"));

pub fn lookup_mut(&mut self, path: &str) -> Option<&mut Value>

Looks up a mutable reference to a value by a dotted path like “application.window.title”

Returns None if any part of the path doesn’t exist. Supports both bracket notation (items.[0]) and bare numeric (items.0).

Examples

use libconfig::Value;

let config = r#"
    {
        ports = [80, 443];
    }
"#;

let mut v = Value::from_str(config).unwrap();
*v.lookup_mut("ports.[0]").unwrap() = Value::Integer(8080);
assert_eq!(v["ports.0"], 8080);

pub fn set(&mut self, path: &str, value: Value) -> Option<()>

Sets a value at the given path, creating intermediate Group nodes as needed.

Returns Some(()) on success, or None if the path is invalid or an intermediate value is not a Group/Array/List.

Array/list indices must refer to existing elements (no auto-extension).

Examples

use libconfig::Value;
use indexmap::IndexMap;

let mut v = Value::Group(IndexMap::new());
v.set("a.b.c", Value::Integer(42));
assert_eq!(v.lookup("a.b.c").unwrap().as_i32(), Some(42));

pub fn remove(&mut self, path: &str) -> Option<Value>

Removes a value at the given path and returns it.

For group members, the key-value pair is removed. For array/list elements, the element is removed and subsequent elements shift down.

Returns None if the path is invalid or the target doesn’t exist.

Examples

use libconfig::Value;

let mut v = Value::from_str(r#"{ a = 1; b = 2; c = 3; }"#).unwrap();
let removed = v.remove("b");
assert_eq!(removed, Some(Value::Integer(2)));
assert!(v.lookup("b").is_none());

pub fn to_string(&self) -> Result<String>

Serialize this value to a libconfig string.

The output always wraps top-level groups in braces. For implicit (no braces) output, use Config::from or Config::from_str.

Examples

use libconfig::Value;

let v = Value::Integer(42);
assert_eq!(v.to_string().unwrap(), "42");

Trait Implementations

impl Clone for Config

fn clone(&self) -> Config

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Config

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Config

fn default() -> Self

Returns the “default value” for a type.

impl Deref for Config

type Target = Value

The resulting type after dereferencing.

fn deref(&self) -> &Value

Dereferences the value.

impl DerefMut for Config

fn deref_mut(&mut self) -> &mut Value

Mutably dereferences the value.

impl Display for Config

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<Value> for Config

fn from(value: Value) -> Self

Converts to this type from the input type.

impl PartialEq for Config

fn eq(&self, other: &Config) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Config

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Config