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//! `F32AbsValAtMost1` struct for constrained float between -1 and 1
//! Ensures floating-point values are within valid range at construction
use crate::Error;
use serde::{Deserialize, Serialize};
use std::fmt;
use std::str::FromStr;
/// Datatype holding a float (f32) between -1 and 1 (both inclusive) guaranteed at creation.
#[derive(Debug, Clone, Default, Copy, PartialOrd, PartialEq, Serialize, Deserialize)]
#[serde(try_from = "f32")]
pub struct F32AbsValAtMost1(f32);
impl F32AbsValAtMost1 {
/// Constructor, will fail if float is not between -1 and 1
///
/// ```should_panic
/// use nanalogue_core::Error;
/// use nanalogue_core::F32AbsValAtMost1;
/// let x = F32AbsValAtMost1::new(-1.1).unwrap();
/// ```
/// ```should_panic
/// # use nanalogue_core::Error;
/// # use nanalogue_core::F32AbsValAtMost1;
/// let x = F32AbsValAtMost1::new(1.1).unwrap();
/// ```
/// ```
/// # use nanalogue_core::Error;
/// # use nanalogue_core::F32AbsValAtMost1;
/// let x = F32AbsValAtMost1::new(0.1)?;
/// # Ok::<(), nanalogue_core::Error>(())
/// ```
/// ```
/// # use nanalogue_core::Error;
/// # use nanalogue_core::F32AbsValAtMost1;
/// let x = F32AbsValAtMost1::new(-0.5)?;
/// # Ok::<(), nanalogue_core::Error>(())
/// ```
///
/// # Errors
/// Returns an error if the value is not between -1.0 and 1.0 (inclusive).
pub fn new(val: f32) -> Result<Self, Error> {
if (-1.0..=1.0).contains(&val) {
Ok(F32AbsValAtMost1(val))
} else {
Err(Error::InvalidState("Num not b/w -1 and 1!".to_string()))
}
}
/// Returns the value of the float.
///
/// ```
/// use nanalogue_core::F32AbsValAtMost1;
/// for y in vec![0.0,0.1,-0.7,1.0,-1.0]{
/// let x = F32AbsValAtMost1::new(y.clone())?;
/// assert_eq!(x.val(), y);
/// }
/// # Ok::<(), nanalogue_core::Error>(())
/// ```
#[must_use]
pub fn val(&self) -> f32 {
self.0
}
}
impl FromStr for F32AbsValAtMost1 {
type Err = Error;
/// Parse a string to obtain float and then convert if b/w -1 and 1
///
/// ```
/// use nanalogue_core::F32AbsValAtMost1;
/// use std::str::FromStr;
///
/// // Boundary values - exactly -1.0, 0.0, and 1.0 should work
/// let neg_one = F32AbsValAtMost1::from_str("-1.0")?;
/// assert_eq!(neg_one.val(), -1.0);
/// let zero = F32AbsValAtMost1::from_str("0.0")?;
/// assert_eq!(zero.val(), 0.0);
/// let one = F32AbsValAtMost1::from_str("1.0")?;
/// assert_eq!(one.val(), 1.0);
/// # Ok::<(), nanalogue_core::Error>(())
/// ```
///
/// ```
/// # use nanalogue_core::F32AbsValAtMost1;
/// # use std::str::FromStr;
/// #
/// // Near-boundary values
/// let near_neg_one = F32AbsValAtMost1::from_str("-0.999999")?;
/// let near_one = F32AbsValAtMost1::from_str("0.999999")?;
/// # Ok::<(), nanalogue_core::Error>(())
/// ```
///
/// ```should_panic
/// # use nanalogue_core::F32AbsValAtMost1;
/// # use std::str::FromStr;
/// #
/// // Just outside boundaries should fail
/// let outside = F32AbsValAtMost1::from_str("-1.000001")?;
/// # Ok::<(), nanalogue_core::Error>(())
/// ```
fn from_str(val_str: &str) -> Result<Self, Self::Err> {
Self::new(f32::from_str(val_str)?)
}
}
impl fmt::Display for F32AbsValAtMost1 {
/// converts to string for display.
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.val().fmt(f)
}
}
impl TryFrom<f32> for F32AbsValAtMost1 {
type Error = Error;
/// attempts conversion from `f32`, will succeed if -1 <= value <= 1
///
/// # Errors
/// If conversion doesn't work.
///
/// # Examples
/// ```
/// use nanalogue_core::{Error, F32AbsValAtMost1};
///
/// let val1: F32AbsValAtMost1 = 0.5f32.try_into().unwrap();
/// let val2: F32AbsValAtMost1 = (-0.7_f32).try_into().unwrap();
/// let val3: Error = F32AbsValAtMost1::try_from(1.7).unwrap_err();
/// ```
fn try_from(value: f32) -> Result<Self, Self::Error> {
F32AbsValAtMost1::new(value)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn f32_abs_val_at_most1_basic() {
// Test boundary values
let _: F32AbsValAtMost1 = F32AbsValAtMost1::new(-1.0).unwrap();
let _: F32AbsValAtMost1 = F32AbsValAtMost1::new(1.0).unwrap();
let _: F32AbsValAtMost1 = F32AbsValAtMost1::new(0.0).unwrap();
// Test near-boundary values
let _: F32AbsValAtMost1 = F32AbsValAtMost1::new(-0.999_999).unwrap();
let _: F32AbsValAtMost1 = F32AbsValAtMost1::new(0.999_999).unwrap();
// Test outside boundaries
let _: Error = F32AbsValAtMost1::new(-1.000_001).unwrap_err();
let _: Error = F32AbsValAtMost1::new(1.000_001).unwrap_err();
}
#[test]
fn f32_abs_val_at_most1_from_str() {
// Valid strings
let _: F32AbsValAtMost1 = F32AbsValAtMost1::from_str("-1.0").unwrap();
let _: F32AbsValAtMost1 = F32AbsValAtMost1::from_str("1.0").unwrap();
let _: F32AbsValAtMost1 = F32AbsValAtMost1::from_str("0.0").unwrap();
let _: F32AbsValAtMost1 = F32AbsValAtMost1::from_str("-0.5").unwrap();
let _: F32AbsValAtMost1 = F32AbsValAtMost1::from_str("0.5").unwrap();
// Invalid strings
let _: Error = F32AbsValAtMost1::from_str("-1.1").unwrap_err();
let _: Error = F32AbsValAtMost1::from_str("1.1").unwrap_err();
let _: Error = F32AbsValAtMost1::from_str("abc").unwrap_err();
let _: Error = F32AbsValAtMost1::from_str("").unwrap_err();
}
#[expect(
clippy::shadow_unrelated,
reason = "repetition is fine; each block is clearly separated"
)]
#[test]
fn f32_abs_val_at_most1_display() {
let val = F32AbsValAtMost1::new(-0.5).expect("should create");
assert_eq!(format!("{val}"), "-0.5");
let val = F32AbsValAtMost1::new(0.75).expect("should create");
assert_eq!(format!("{val}"), "0.75");
}
#[test]
#[expect(
clippy::float_cmp,
reason = "exact compare ok as (1) very few significant digits, and (2) no arithmetic"
)]
fn f32_abs_val_at_most1_val() {
for test_val in [0.0, 0.1, -0.7, 1.0, -1.0] {
let val = F32AbsValAtMost1::new(test_val).expect("should create");
assert_eq!(val.val(), test_val);
}
}
#[test]
#[expect(
clippy::float_cmp,
reason = "exact comparison ok for boundary values and simple fractions"
)]
fn f32_abs_val_at_most1_try_from_f32_valid() {
// Test boundary values
let neg_one: F32AbsValAtMost1 = (-1.0f32).try_into().expect("should convert");
assert_eq!(neg_one.val(), -1.0);
let zero: F32AbsValAtMost1 = 0.0f32.try_into().expect("should convert");
assert_eq!(zero.val(), 0.0);
let one: F32AbsValAtMost1 = 1.0f32.try_into().expect("should convert");
assert_eq!(one.val(), 1.0);
// Test intermediate positive values
let half: F32AbsValAtMost1 = 0.5f32.try_into().expect("should convert");
assert_eq!(half.val(), 0.5);
// Test intermediate negative values
let neg_half: F32AbsValAtMost1 = (-0.5f32).try_into().expect("should convert");
assert_eq!(neg_half.val(), -0.5);
let neg_three_quarters: F32AbsValAtMost1 = (-0.75f32).try_into().expect("should convert");
assert_eq!(neg_three_quarters.val(), -0.75);
// Test near-boundary values
let near_neg_one: F32AbsValAtMost1 = (-0.999_999f32).try_into().expect("should convert");
assert_eq!(near_neg_one.val(), -0.999_999);
let near_one: F32AbsValAtMost1 = 0.999_999f32.try_into().expect("should convert");
assert_eq!(near_one.val(), 0.999_999);
}
#[test]
fn f32_abs_val_at_most1_try_from_f32_invalid() {
// Test below lower boundary
let below_neg_one: Result<F32AbsValAtMost1, _> = (-1.000_001f32).try_into();
let _: Error = below_neg_one.unwrap_err();
let too_negative: Result<F32AbsValAtMost1, _> = (-1.5f32).try_into();
let _: Error = too_negative.unwrap_err();
// Test above upper boundary
let above_one: Result<F32AbsValAtMost1, _> = 1.000_001f32.try_into();
let _: Error = above_one.unwrap_err();
let too_large: Result<F32AbsValAtMost1, _> = 1.5f32.try_into();
let _: Error = too_large.unwrap_err();
// Test special float values
let infinity: Result<F32AbsValAtMost1, _> = f32::INFINITY.try_into();
let _: Error = infinity.unwrap_err();
let neg_infinity: Result<F32AbsValAtMost1, _> = f32::NEG_INFINITY.try_into();
let _: Error = neg_infinity.unwrap_err();
}
}