ling-ast

//! Source span — byte-offset range within a source file.

use serde::{Deserialize, Serialize};

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Default, Serialize, Deserialize)]
pub struct Span {
    pub start: u32,
    pub end: u32,
}

impl Span {
    pub const DUMMY: Self = Self { start: 0, end: 0 };

    pub fn new(start: u32, end: u32) -> Self {
        Self { start, end }
    }

    pub fn len(self) -> u32 {
        self.end.saturating_sub(self.start)
    }

    pub fn is_empty(self) -> bool {
        self.len() == 0
    }

    pub fn union(self, other: Self) -> Self {
        Self {
            start: self.start.min(other.start),
            end: self.end.max(other.end),
        }
    }
}

impl std::fmt::Display for Span {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}..{}", self.start, self.end)
    }
}