sqrid

sqrid provides square grid coordinates and related operations, in a single-file create, with no dependencies.

Qa: absolute coordinates, position

The Qa type represents an absolute position in a square grid. The type itself receives the height and width of the grid as const generic parameter.

We should usually create a type alias for the grid size we are using:

use sqrid;

type Qa = sqrid::Qa<6, 7>;

We can get Qa instances by:

• Using one of the const associated items:

  type Qa = sqrid::Qa<6, 7>;
  const MyFirst : Qa = Qa::FIRST;
  const MyLast : Qa = Qa::LAST;
  

• Using try_from with a (i16, i16) tuple or a tuple reference:

  use std::convert::TryFrom;
  use std::error::Error;
  
  type Qa = sqrid::Qa<6, 7>;
  const MyFirst : Qa = Qa::FIRST;
  
  fn main() -> Result<(), Box<dyn Error>> {
      let qa1 = Qa::try_from((2_i16, 3_i16))?;
  
      println!("qa1: {}", qa1);
      Ok(())
  }
  

• Calling Qa::new, which checks the bounds in const contexts:

  type Qa = sqrid::Qa<6, 7>;
  const MY_FIRST : Qa = Qa::new::<3, 4>();
  

  The following, for instance, doesn't compile:

  type Qa = sqrid::Qa<6, 7>;
  const MY_FIRST : Qa = Qa::new::<12, 4>();
  

• Calling Qa::iter to iterate all coordinates in the grid:

  type Qa = sqrid::Qa<6, 7>;
  for qa in Qa::iter() {
      println!("{}", qa);
  }
  

Qr: relative coordinates, direction, movement

This type represents a relative movement of one square. It can only be one of the 4 cardinal directions (N, E, S, W) if the DIAG argument is false, or one of the 8 directions when it's true.

It's a building block for paths, iterating on a Qa neighbors, etc. It effectively represents the edges in a graph where the Qa type represents nodes.

We can get Qr instances by:

• Using one of the const associated items that represent all cardinal directions (recommended):

  use sqrid::Qr;
  const Right : Qr<false> = Qr::E;
  const Down : Qr<false> = Qr::S;
  

• Using try_from with a (i16, i16) tuple or a tuple reference:

  use std::convert::TryFrom;
  use std::error::Error;
  
  use sqrid::Qr;
  
  fn main() -> Result<(), Box<dyn Error>> {
      // Re-create West:
      let qr1 = Qr::<false>::try_from((0_i16, -1_i16))?;
      // Re-create Northeast:
      let qr2 = Qr::<true>::try_from((-1_i16, 1_i16))?;
      Ok(())
  }
  

• Calling Qr::new, which checks the bounds in const contexts:

  use sqrid::Qr;
  const DOWNRIGHT : Qr<true> = Qr::<true>::new::<1, 1>();
  

  The following, for instance, doesn't compile due to the argument being false, which means that diagonals are not supported:

  use sqrid::Qr;
  const DOWNRIGHT : Qr<false> = Qr::<false>::new::<1, 1>();
  

• Calling Qr::iter to iterate all directions:

  for qr in sqrid::Qr::<true>::iter() {
      println!("{}", qr);
  }