A parser for Leonardo, a program inspired by Logo.

Commands include:

Command	Result
FORW d	Leonardo moves forward d steps (for a positive integer d)
BACK d	Leonardo moves backwards d steps (for a positive integer d)
LEFT a	Leonardo turns left a degrees, without changing position
RIGHT a	Leonardo turns right a degrees, without changing position
DOWN	Leonardo lowers the pencil so that it leaves a trail when Leonardo moves
UP	Leonardo raises the pencil so that it leaves no trail when Leonardo moves
COLOR c	changes the color of the pen to the color c . Color is specified in hex format, e.g. #FFA500 for orange.
REP r	Leonardo repeats r times (for a positive integer r). is a sequence of one or more instructions, surrounded by quotation marks ('"'). If the sequence consists of only a single instruction, the quotation marks are optional

A formal grammar in Backus–Naur form is also defined.