Build on previous commits to define extract(_inner)_lossy.

These functions behave the same as extract(_inner), but they
accept appropriate strings and numbers in places of booleans,
and appropriate strings in place of numbers.

src/figment.rs

@@ -4,7 +4,7 @@ use serde::de::Deserialize;
 
 use crate::{Profile, Provider, Metadata};
 use crate::error::{Kind, Result};
-use crate::value::{Value, Map, Dict, Tag, ConfiguredValueDe, DefaultPrimHandler};
+use crate::value::{Value, Map, Dict, Tag, ConfiguredValueDe, DefaultPrimHandler, LossyPrimHandler};
 use crate::coalesce::{Coalescible, Order};
 
 /// Combiner of [`Provider`]s for configuration value extraction.
@@ -485,6 +485,60 @@ impl Figment {
         T::deserialize(ConfiguredValueDe::<'_,DefaultPrimHandler>::from(self, &self.merged()?))
     }
 
+    /// As [`extract`](Figment::extract_lossy), but interpret numbers and booleans more flexibly.
+    ///
+    /// See [`Value::to_bool_lossy`] and [`Value::to_num_lossy`] for a full explanation
+    /// of the imputs accepted.
+    ///
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use serde::Deserialize;
+    ///
+    /// use figment::{Figment, providers::{Format, Toml, Json, Env}};
+    ///
+    /// #[derive(Debug, PartialEq, Deserialize)]
+    /// struct Config {
+    ///     name: String,
+    ///     numbers: Option<Vec<usize>>,
+    ///     debug: bool,
+    /// }
+    ///
+    /// figment::Jail::expect_with(|jail| {
+    ///     jail.create_file("Config.toml", r#"
+    ///         name = "test"
+    ///         numbers = ["1", "2", "3", "10"]
+    ///     "#)?;
+    ///
+    ///     jail.set_env("config_name", "env-test");
+    ///
+    ///     jail.create_file("Config.json", r#"
+    ///         {
+    ///             "name": "json-test",
+    ///             "debug": "yes"
+    ///         }
+    ///     "#)?;
+    ///
+    ///     let config: Config = Figment::new()
+    ///         .merge(Toml::file("Config.toml"))
+    ///         .merge(Env::prefixed("CONFIG_"))
+    ///         .join(Json::file("Config.json"))
+    ///         .extract_lossy()?;
+    ///
+    ///     assert_eq!(config, Config {
+    ///         name: "env-test".into(),
+    ///         numbers: vec![1, 2, 3, 10].into(),
+    ///         debug: true
+    ///     });
+    ///
+    ///     Ok(())
+    /// });
+    /// ```
+    pub fn extract_lossy<'a, T: Deserialize<'a>>(&self) -> Result<T> {
+        T::deserialize(ConfiguredValueDe::<'_,LossyPrimHandler>::from(self, &self.merged()?))
+    }
+
     /// Deserializes the value at the `key` path in the collected value into
     /// `T`.
     ///
@@ -514,6 +568,37 @@ impl Figment {
         T::deserialize(ConfiguredValueDe::<'_,DefaultPrimHandler>::from(self, &self.find_value(key)?))
     }
 
+    /// As [`extract`](Figment::extract_lossy), but interpret numbers and booleans more flexibly.
+    ///
+    /// See [`Value::to_bool_lossy`] and [`Value::to_num_lossy`] for a full explanation
+    /// of the imputs accepted.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use figment::{Figment, providers::{Format, Toml, Json}};
+    ///
+    /// figment::Jail::expect_with(|jail| {
+    ///     jail.create_file("Config.toml", r#"
+    ///         numbers = ["1", "2", "3", "10"]
+    ///     "#)?;
+    ///
+    ///     jail.create_file("Config.json", r#"{ "debug": true } "#)?;
+    ///
+    ///     let numbers: Vec<usize> = Figment::new()
+    ///         .merge(Toml::file("Config.toml"))
+    ///         .join(Json::file("Config.json"))
+    ///         .extract_inner_lossy("numbers")?;
+    ///
+    ///     assert_eq!(numbers, vec![1, 2, 3, 10]);
+    ///
+    ///     Ok(())
+    /// });
+    /// ```
+    pub fn extract_inner_lossy<'a, T: Deserialize<'a>>(&self, key: &str) -> Result<T> {
+        T::deserialize(ConfiguredValueDe::<'_,LossyPrimHandler>::from(self, &self.find_value(key)?))
+    }
+
     /// Returns an iterator over the metadata for all of the collected values in
     /// the order in which they were added to `self`.
     ///

src/value/de.rs

@@ -29,6 +29,25 @@ impl PrimHandler for DefaultPrimHandler {
     }
 }
 
+#[derive(Default)]
+pub struct LossyPrimHandler{}
+impl PrimHandler for LossyPrimHandler {
+    fn interpret_as_bool(v: &Value) -> Result<Cow<'_, Value>> {
+	Ok(if let Some(b) = v.to_bool_lossy() {
+            Cow::Owned(Value::Bool(v.tag(), b))
+        } else {
+            Cow::Borrowed(v)
+        })
+    }
+    fn interpret_as_num(v: &Value) -> Result<Cow<'_, Value>> {
+	Ok(if let Some(n) = v.to_num_lossy() {
+	    Cow::Owned(Value::Num(v.tag(), n))
+	} else {
+	    Cow::Borrowed(v)
+	})
+    }
+}
+
 pub struct ConfiguredValueDe<'c, PH=DefaultPrimHandler> {
     pub config: &'c Figment,
     pub value: &'c Value,

tests/lossy_values.rs

@@ -0,0 +1,28 @@
+use serde::Deserialize;
+use figment::{Figment, providers::{Toml, Format}};
+
+#[derive(Debug, Deserialize, PartialEq)]
+struct Config {
+    bs: Vec<bool>,
+    u8s: Vec<u8>,
+    i32s: Vec<i32>,
+    f64s: Vec<f64>,
+}
+
+static TOML: &str = r##"
+    u8s = [1, 2, 3, "4", 5, "6"]
+    i32s = [-1, -2, 3, "-4", 5, "6"]
+    f64s = [1, "2", -3, -4.5, "5.0", "-6.0"]
+    bs = [true, false, "true", "false", "YES", "no", "on", "OFF", "1", "0", 1, 0]
+"##;
+
+#[test]
+fn lossy_values() {
+    let config: Config = Figment::from(Toml::string(TOML)).extract_lossy().unwrap();
+    assert_eq!(&config.u8s, &[ 1, 2, 3, 4, 5, 6 ]);
+    assert_eq!(&config.i32s, &[-1, -2, 3, -4, 5, 6]);
+    assert_eq!(&config.f64s, &[1.0, 2.0, -3.0, -4.5, 5.0, -6.0]);
+    assert_eq!(&config.bs, &[
+        true, false, true, false, true, false, true, false, true, false, true, false
+    ]);
+}