Function hash_syntax

crates/common/src/env.rs:687–718

(syn: &Syntax, hasher: &mut blake3::Hasher)

      }
    },
  }
}

/// A Lean 4 concrete syntax tree node.
#[derive(Debug, PartialEq, Eq, Clone, Hash)]
pub enum Syntax {
  /// Placeholder for missing syntax.
  Missing,
  /// An interior syntax node with a kind name and child nodes.
  Node(SourceInfo, Name, Vec<Syntax>),
  /// An atomic token (keyword, symbol, etc.).
  Atom(SourceInfo, String),
  /// An identifier with optional pre-resolved references.
  Ident(SourceInfo, Substring, Name, Vec<SyntaxPreresolved>),
}

fn hash_syntax(syn: &Syntax, hasher: &mut blake3::Hasher) {
  hasher.update(&[MSYN]);
  match syn {
    Syntax::Missing => {
      hasher.update(&[0]);
    },
    Syntax::Node(info, kind, args) => {
      hasher.update(&[1]);
      hash_source_info(info, hasher);
      hasher.update(kind.get_hash().as_bytes());
      hasher.update(&Nat::from(args.len() as u64).to_le_bytes());
      for arg in args {
        hash_syntax(arg, hasher);
      }
    },
    Syntax::Atom(info, val) => {
      hasher.update(&[2]);
      hash_source_info(info, hasher);
      hasher.update(val.as_bytes());