Function pi

crates/kernel/src/whnf.rs:3515–3517

(a: AE, b: AE)

      let joined = format!("{sa}{sb}");
      let blob_addr = Address::hash(joined.as_bytes());
      return Ok(Some(self.intern(KExpr::str(joined, blob_addr))));
    }

    if *addr == self.prims.string_dec_eq.addr {
      if args.len() != 2 {
        return Ok(None);