Browsable Pico Grammar

Grammar connected by Vadim Zaytsev, see the Grammar Zoo entry for details: toy/pico/unknown/sdf/connected
Source used for this grammar: Jurgen Vinju, Pico.sdf, Identifiers.sdf, Types.sdf, February 2006 – September 2007

Summary

• Total 6 production rules with 16 top alternatives and 98 symbols.
• Vocabulary: 31 = 9 nonterminals + 22 terminals + 0 labels + 0 markers.
• Total 9 nonterminal symbols: 6 defined (PROGRAM, DECLS, ID-TYPE, TYPE, STATEMENT, EXP), 1 root (PROGRAM), 0 top (—), 3 bottom (StrCon, PICO-ID ³, NatCon).
• Total 22 terminal symbols: 12 keywords ("begin", "end", "declare", "natural", "string", "if", "then", "else", "fi", "while", "do", "od"), 0 letters (—), 0 numerics (—), 9 signs (";" ⁵, ",", ":", ":=", "+", "-", "||", "(", ")").

Syntax

PROGRAM ::=
	"begin" DECLS (STATEMENT (";" STATEMENT)*)? "end"

DECLS ::=
	"declare" (ID-TYPE ("," ID-TYPE)*)? ";"

ID-TYPE ::=
	PICO-ID ":" TYPE

TYPE ::=
	"natural"
	"string"
	"nil-type"

STATEMENT ::=
	PICO-ID ":=" EXP
	"if" EXP "then" (STATEMENT (";" STATEMENT)*)? "else" (STATEMENT (";" STATEMENT)*)? "fi"
	"while" EXP "do" (STATEMENT (";" STATEMENT)*)? "od"

EXP ::=
	PICO-ID
	NatCon
	StrCon
	EXP "+" EXP
	EXP "-" EXP
	EXP "||" EXP
	"(" EXP ")"

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