.LIF File Format

Introduction

Life 1.06 is a Game of Life pattern file that lists the live cells and nothing else. The first line is #Life 1.06, and every line after it is the position of one live cell: its x coordinate, a space and its y coordinate, as whole numbers. A pattern that is spread over a huge area costs only its cells, which is what the Life 1.05 blocks of dots and stars cannot do.

It is not the format of the program called Life 1.06, Alan Hensel’s MS-DOS program, which reads and writes Life 1.05 files.

What is checked here. There is no Life 1.06 file on the Mac this site is written from, and none of the documents there describe it. This page is written from memory of the format, which Golly also reads, and the explorer’s reading has been tried only on files made for the tests. Every claim below about the meaning of the numbers is unchecked against a real file, so this reference is marked partial.

Lines

Cells

The numbers are positions relative to an origin, 0 0, which a program is free to put where it likes on its screen. The explorer takes x as growing to the right and y as growing downwards, as in a Life 1.05 block. A cell that is listed twice is alive once. The cells may come in any order; an exact order is not required, and none is assumed. There are no rules: the program uses the rules it is set to, which for a pattern from the Game of Life means Conway’s.

The explorer reads positions up to ±33,554,431. A line with a larger number is noted, the cell is left out and the file is shown as damaged.

An example

A glider written as a list, made for this page and the explorer’s tests; it is not a file from the Mac. Line endings are 0D 0A, though any of the three kinds is read.

23 4C 69 66 65 20 31 2E 30 36 0D 0A      #Life 1.06
30 20 2D 31 0D 0A                        0 -1
31 20 30 0D 0A                           1 0
2D 31 20 31 0D 0A                        -1 1
30 20 31 0D 0A                           0 1
31 20 31 0D 0A                           1 1

Five cells in a box from x −1 to 1 and y −1 to 1: the same glider as .*. / ..* / *** with its middle cell at the origin.

Not described

This is what the reference leaves out and what the viewer does not do.

• Reference: the whole page is from memory. No Life 1.06 file or document is on the Mac, so the layout, the direction of y, the handling of comments and duplicate cells, and the largest coordinates are unchecked.
• Reference: any rules, header fields or extensions a Life 1.06 file might carry are not described.
• Viewer: it draws only the first generation and does not run any rules. It has been tried only on files made for its tests.
• Viewer: positions beyond ±33,554,431 are noted and the cell left out; # lines are read as comments.

Variants

• Life 1.05 pattern – a version line, description, rules and cell blocks of dots and stars
• Life 1.06 pattern – a version line and one live cell a line, as two numbers
• Life pattern without a version line – the Life 1.05 layout with no first line, and bare grids of dots and stars
• Life pattern (x grid) – rows of x and spaces with no header

Links