CompSci 307 : Fall 2021

OOLALA: Darwin Simulator

This language was invented by Nick Parlante at Stanford University where it was a classic final assignment for CS106B (their version of CompSci 101).

Create an interactive simulator for a world populated by a number of creatures, showing each creature's current species, location, and orientation, to see how they interact together (and perhaps which species dominates!).

A creature's species is determined by the program it executes each step so all creatures of the species behave the same way (by running the same program although they may each be at a different instruction of their program). A step of the simulation is completed when all non-infected creatures have run one step of their program (i.e., if a creature is infected during a step, then it does not get a chance to run its new program). The order in which creatures are selected to run their program should be random so as not to bias the simulation.

In addition to the UI features common to all applications, it should all allow the user to:

set the radius determining how far "nearby" is for a creature to sense its environment
add a kind of species to the world at a specific xy-location (default is the center of the display)
set an image to use for a species
set how fast the animation updates the simulation
pause and resume the simulation

Example

This is an example of a typical program:

Program Notes Reference
# Flytrap species
ifenemy 4
left 90
go 1
infect
go 1
If a creature is ahead nearby, go to instruction 4
Turn left 90 degrees
Go back to instruction 1
Infect the other creature
Go back to instruction 1

Instruction 1
Instruction 2
Instruction 3
Instruction 4
Instruction 5

Program	Notes	Reference
# Flytrap species ifenemy 4 left 90 go 1 infect go 1	If a creature is ahead nearby, go to instruction 4 Turn left 90 degrees Go back to instruction 1 Infect the other creature Go back to instruction 1	Instruction 1 Instruction 2 Instruction 3 Instruction 4 Instruction 5

More examples are given here, but you are expected to make your own example files as well (including ones with syntactically incorrect programs).

Programs

A creature evaluates part of its program each step in which it may look in front of itself to see what’s there and then take some action. Thus a program evaluates any number of IF or GO instructions in a single step and a step ends when the program executes an action (one of the instructions HOP, LEFT, RIGHT, or INFECT). The program starts subsequent steps at the next instruction after the last one executed.

Commands

Name Description

MOVE pixels Move creature forward by the given pixels in the direction it is facing.
If moving forward would put the creature outside the world's boundaries or cause it to land on another creature, then this instruction does nothing.

LEFT degrees Turn creature in place left by the given degrees

RIGHT degrees Turn creature in place right by the given degrees

INFECT Change a creature of a different species (an “enemy”) in the space nearby ahead into this kind of creature
When a creature is infected, it changes its internal program to the same as the infecting creature (i.e., it becomes one of them)
If there is no creature in the space nearby ahead, then this instruction does nothing

IFEMPTY instruction Perform the given instruction next only if the space nearby ahead of the creature is empty and inside the world's boundary;
otherwise, go on with the next instruction

IFWALL instruction Perform the given instruction next only if the space nearby ahead of the creature is the world's boundary;
otherwise, go on with the next instruction

IFSAME instruction Perform the given instruction next only if the space nearby ahead of the creature is occupied by a creature of the same species;
otherwise, go on with the next instruction

IFENEMY instruction Perform the given instruction next only if the space nearby ahead of the creature is occupied by a creature of a different species;
otherwise, go on with the next instruction

IFRANDOM instruction Perform the given instruction next half of the time (otherwise continue with the next instruction half of the time)
This allows some creatures to exercise what might be called the rudiments of “free will”

GO instruction Perform the given instruction next, rather than the next instruction (if present)

Name	Description
MOVE pixels	Move creature forward by the given pixels in the direction it is facing. If moving forward would put the creature outside the world's boundaries or cause it to land on another creature, then this instruction does nothing.
LEFT degrees	Turn creature in place left by the given degrees
RIGHT degrees	Turn creature in place right by the given degrees
INFECT	Change a creature of a different species (an “enemy”) in the space nearby ahead into this kind of creature When a creature is infected, it changes its internal program to the same as the infecting creature (i.e., it becomes one of them) If there is no creature in the space nearby ahead, then this instruction does nothing
IFEMPTY instruction	Perform the given instruction next only if the space nearby ahead of the creature is empty and inside the world's boundary; otherwise, go on with the next instruction
IFWALL instruction	Perform the given instruction next only if the space nearby ahead of the creature is the world's boundary; otherwise, go on with the next instruction
IFSAME instruction	Perform the given instruction next only if the space nearby ahead of the creature is occupied by a creature of the same species; otherwise, go on with the next instruction
IFENEMY instruction	Perform the given instruction next only if the space nearby ahead of the creature is occupied by a creature of a different species; otherwise, go on with the next instruction
IFRANDOM instruction	Perform the given instruction next half of the time (otherwise continue with the next instruction half of the time) This allows some creatures to exercise what might be called the rudiments of “free will”
GO instruction	Perform the given instruction next, rather than the next instruction (if present)

General notes about a program's syntax:

Tokens are separated by one or more spaces, tabs, or newlines
Command names are not case sensitive (even though they are shown below in all capital letters)
Ignore any lines that are empty, i.e., only zero or more spaces, or begin with comment character, "#"
Programs start with instruction 1, comments and blank lines do not count as instructions

Resources

The original assignment specification
Note, the requirements are slightly different than this project and the implementation notes given do not necessarily agree with modern OO design principles, so they should not be copied without justification.