Turtle Talk EBNF

gistfile1.txt

identifier        := (A-Z,"_")
var_name          := ":"<identifier>
command           := "FD" | "BD" | "LT" | "RT" | "PEN"
positive_integer  := \d+
expression        := <positive_integer> | "UP" | "DOWN" | <var_name> | <positive_integer> ("+" | "-") <expression>
command_statement := (<command_key> | <identifier>) <expression>
loop_statement    := "REPEAT" <positive_integer> { <command> } "END"
statement         := <loop_statement> | <command_statement>
fun_definition    := "TO" <identifier> [ <var_name> ] { "," <var_name> } { <statement> } "END"