Browsable Logo Grammar

Grammar extracted by Vadim Zaytsev, see the Grammar Zoo entry for details: logo/klint/extracted
Source used for this grammar: Paul Klint, Logo.sdf, March 2007 [GitHub]

Summary

• Total 9 production rules with 80 top alternatives and 179 symbols.
• Vocabulary: 51 = 13 nonterminals + 38 terminals + 0 labels + 0 markers.
• Total 13 nonterminal symbols: 9 defined (Program, Commands, Command, BasicCommand, Exp, Block, FunctionDef, Id, Call), 1 root (Program), 0 top (—), 4 bottom (Integer, Color, QuotedId ², Formal ²).
• Total 38 terminal symbols: 31 keywords ("if" ², "ifelse" ², "repeat" ², "forward" ², "back" ², "left" ², "right" ², "setxy" ², "setx" ², "sety" ², "home" ², "showturtle" ², "hideturtle" ², "clean" ², "clearscreen" ², "pendown" ², "penup" ², "pencolor", "local" ², "make" ², "xcor" ², "ycor" ², "heading" ², "towards" ², "sum" ², "difference" ², "product" ², "quotient" ², "remainder" ², "minus" ², "to" ²), 0 letters (—), 0 numerics (—), 2 signs ("[", "]").

Syntax

Program ::=
	Commands

Commands ::=
	Command*

Command ::=
	BasicCommand
	FunctionDef
	Call

BasicCommand ::=
	"if" Exp Block
	"ifelse" Exp Block Block
	"repeat" Exp Block
	"forward" Exp
	"back" Exp
	"left" Exp
	"right" Exp
	"setxy" Exp Exp
	"setx" Exp
	"sety" Exp
	"home"
	"showturtle"
	"hideturtle"
	"clean"
	"clearscreen"
	"pendown"
	"penup"
	"pencolor" Color
	"local" QuotedId
	"make" QuotedId Exp

Exp ::=
	Integer
	Formal
	"xcor"
	"ycor"
	"heading"
	"towards" Exp Exp
	"pendown?"
	"sum" Exp Exp
	"difference" Exp Exp
	"product" Exp Exp
	"quotient" Exp Exp
	"remainder" Exp Exp
	"minus" Exp
	"less?" Exp Exp
	"greater?" Exp Exp
	"equal?" Exp Exp
	"notequal?" Exp Exp

Block ::=
	"[" Command* "]"

FunctionDef ::=
	"to" Id Formal* Block

Id ::=
	"xcor"
	"ycor"
	"heading"
	"towards"
	"pendown?"
	"sum"
	"difference"
	"product"
	"quotient"
	"remainder"
	"minus"
	"less?"
	"greater?"
	"equal?"
	"notequal?"
	"to"
	"if"
	"ifelse"
	"repeat"
	"forward"
	"back"
	"left"
	"right"
	"setxy"
	"setx"
	"sety"
	"home"
	"showturtle"
	"hideturtle"
	"clean"
	"clearscreen"
	"pendown"
	"penup"
	"local"
	"make"

Call ::=
	Id Exp*

Maintained by Dr. Vadim Zaytsev a.k.a. @grammarware. Last updated in September 2015. [↑]