Tortuga - a Logo implementation in OCaml
Tortuga is an implementation of the Logo programming language in OCaml. It aims to support the language as specified by the Berkley Logo. It is distributed under the MIT license. It is currently under development but it is already functional for simple examples (see below).
Contact: Nicolás Ojeda Bär <[email protected]>.
Installation
Tortuga allows for different graphical backends. The most basic one is provided by OCaml's Graphics module, but it is quite poor. A better option is to use Vg to produce beautiful PDF files. (A javascript-based backend to see the pictures in a web browser is in the works.)
opam install uutf otfm gg vg ounit pa_ounit
cd ~/tmp
git clone https://github.com/nojb/tortuga
cd tortuga
make
Now you can run tortu.byte to start the interpreter.
Example
The Fern
Type the following in a fresh session of the interpreter:
to fern :size :sign
if :size < 1 [ stop ]
fd :size
rt 70 * :sign fern :size * 0.5 :sign * -1 lt 70 * :sign
fd :size
lt 70 * :sign fern :size * 0.5 :sign rt 70 * :sign
rt 7 * :sign fern :size - 1 :sign lt 7 * :sign
bk :size * 2
end
clearscreen pu bk 150 lt 90 fd 90 rt 90 pd
fern 25 1 render
The last command, render, produces the actual pdf file. Don't forget to call
render if you want to see your images!
Output
