Crate lsystem

A Library for specifying an L-System. Formally, L-system formulations consist of a vocabulary set, a starting axiom, and a set of production rules.

In this implementation, LSystem<T> is a fully formulated L-system on the alphabet of all instances of type T. Rule sets are any type that implements the trait LRules<T>.

Examples

Here is how you would write the original algae system used by Lindenmayer:

use lsystem::{LSystem, LRules, MapRules};

let mut rules = MapRules::new();
rules.set_str('A', "AB");
rules.set_str('B', "A");
let axiom = "A".chars().collect();
let mut system = LSystem::new(rules, axiom);
 
let out = system.next().unwrap();
let expected: Vec<char> = "AB".chars().collect();
assert_eq!(expected, out);
 
let out = system.next().unwrap();
let expected: Vec<char> = "ABA".chars().collect();
assert_eq!(expected, out);

let out = system.next().unwrap();
let expected: Vec<char> = "ABAAB".chars().collect();
assert_eq!(expected, out);

This is how you can write the Pythagoras Tree system:

use lsystem::{LSystem, LRules, MapRules};

let mut rules = MapRules::new();
rules.set_str('1', "11");
rules.set_str('0', "1[0]0");
let axiom = "0".chars().collect();
let mut system = LSystem::new(rules, axiom);
 
let out = system.next().unwrap();
let expected: Vec<char> = "1[0]0".chars().collect();
assert_eq!(expected, out);
 
let out = system.next().unwrap();
let expected: Vec<char> = "11[1[0]0]1[0]0".chars().collect();
assert_eq!(expected, out);
 
let out = system.next().unwrap();
let expected: Vec<char> = "1111[11[1[0]0]1[0]0]11[1[0]0]1[0]0".chars().collect();
assert_eq!(expected, out);

The MapRules struct is not restricted to strings. You can just as easily use any type that can be stored in a hashmap.

use lsystem::{LSystem, LRules, MapRules};

let mut rules = MapRules::new();
rules.set(0, vec![1, 0]);
rules.set(1, vec![0, 1, 1]);
let axiom = vec![0];
let mut system = LSystem::new(rules, axiom);

let out = system.next().unwrap();
let expected = vec![1, 0];
assert_eq!(expected, out);

let out = system.next().unwrap();
let expected = vec![0, 1, 1, 1, 0];
assert_eq!(expected, out);

Structs

LSystem

A type containing the full specification for an L-system.

MapRules

A simple production ruleset that maps an atom to an atom string using a lookup table.

Traits

LRules

A set of production rule for an L-system, which maps an item to a list of items which will replace it in the L-system state.

Functions

show

A convenience function to print out the String representation of a char vector.