PROMELA GRAMMAR

Spin Version 6 -- Promela Grammar

The following list defines the grammar of the input language for the SPIN model checker version 6. The notational conventions are as follows.

The name any_ascii_char refers to any printable ASCII character except the double quote character: ".

The statement separator used in this list is the semi-colon ';'. In most cases the semi-colon can be replaced with a two-character arrow symbol: '->', without change of meaning.

In the specification that follows non-terminals are hyper-linked to the production rule where they are defined, and terminals are hyper-linked to the online man-pages for the defining elements of the language.

Grammar Rules

spec	: module [ module ] *

module	: proctype	/* proctype declaration */
	| init		/* init process       */
	| never		/* never claim        */
	| trace		/* event trace        */
	| utype		/* user defined types */
	| mtype		/* mtype declaration  */
	| decl_lst	/* global vars, chans */

proctype: [ active ] PROCTYPE name '(' [ decl_lst ]')'
	  [ priority ] [ enabler ] '{' sequence '}'

init	: INIT [ priority ] '{' sequence '}'

never	: NEVER	'{' sequence '}'

trace	: TRACE '{' sequence '}'

utype	: TYPEDEF name '{' decl_lst '}'

mtype	: MTYPE [ '=' ] '{' name [ ',' name ] * '}'

decl_lst: one_decl [ ';' one_decl ] *

one_decl: [ visible ] typename  ivar [',' ivar ] *

typename: BIT | BOOL | BYTE | SHORT | INT | MTYPE | CHAN
	| uname	/* user defined type names (see utype) */

active  : ACTIVE [ '[' const ']' ]	/* instantiation */

priority: PRIORITY const	/* simulation priority */

enabler : PROVIDED '(' expr ')'	/* execution constraint */

visible	: HIDDEN | SHOW

sequence: step [ ';' step ] *

step    : stmnt	[ UNLESS stmnt ]
	| decl_lst
	| XR varref [',' varref ] *
	| XS varref [',' varref ] *

ivar    : name [ '[' const ']' ] [ '=' any_expr | '=' ch_init ]

ch_init : '[' const ']' OF '{' typename [ ',' typename ] * '}'

varref	: name [ '[' any_expr ']' ] [ '.' varref ]

send    : varref '!' send_args		/* normal fifo send */
	| varref '!' '!' send_args	/* sorted send */

receive : varref '?' recv_args		/* normal receive */
	| varref '?' '?' recv_args	/* random receive */
	| varref '?' '<' recv_args '>'	/* poll with side-effect */
	| varref '?' '?' '<' recv_args '>'	/* ditto */

poll    : varref '?' '[' recv_args ']'	/* poll without side-effect */
	| varref '?' '?' '[' recv_args ']'	/* ditto */

send_args: arg_lst | any_expr '(' arg_lst ')'

arg_lst  : any_expr [ ',' any_expr ] *

recv_args: recv_arg [ ',' recv_arg ] *  |  recv_arg '(' recv_args ')'

recv_arg : varref | EVAL '(' varref ')' | [ '-' ] const

assign  : varref '=' any_expr	/* standard assignment */
	| varref '+' '+'	/* increment */
	| varref '-' '-'	/* decrement */

stmnt	: IF options FI		/* selection */
	| DO options OD		/* iteration */
	| FOR '(' range ')' '{' sequence '}'		/* iteration */
	| ATOMIC '{' sequence '}'	/* atomic sequence */
	| D_STEP '{' sequence '}'	/* deterministic atomic */
	| SELECT '(' range ')'	/* non-deterministic value selection */
	| '{' sequence '}'	/* normal sequence */
	| send
	| receive
	| assign
	| ELSE			/* used inside options */
	| BREAK			/* used inside iterations */
	| GOTO name
	| name ':' stmnt	/* labeled statement */
	| PRINT '(' string [ ',' arg_lst ] ')'
	| ASSERT expr    
	| expr			/* condition */
	| c_code '{' ... '}'	/* embedded C code */
	| c_expr '{' ... '}'
	| c_decl '{' ... '}'
	| c_track '{' ... '}'
	| c_state '{' ... '}'

range	: varref ':' expr '..' expr
	| varref IN varref

options : ':' ':' sequence [ ':' ':' sequence ] *

andor	: '&' '&' | '|' '|'

binarop	: '+' | '-' | '*' | '/' | '%' | '&' | '^' | '|'
	| '>' | '<' | '>' '=' | '<' '=' | '=' '=' | '!' '='
	| '<' '<' | '>' '>' | andor

unarop	: '~' | '-' | '!'

any_expr: '(' any_expr ')'
	| any_expr binarop any_expr
	| unarop any_expr
	| '(' any_expr '-' '>' any_expr ':' any_expr ')'
	| LEN '(' varref ')'	/* nr of messages in chan */
	| poll
	| varref
	| const 
	| TIMEOUT
	| NP_			/* non-progress system state */
	| ENABLED '(' any_expr ')'		/* refers to a pid */
	| PC_VALUE '(' any_expr ')'		/* refers to a pid */
	| name '[' any_expr ']' '@' name	/* refers to a pid */
	| RUN name '(' [ arg_lst ] ')' [ priority ]
	| get_priority( expr )			/* expr refers to a pid */
	| set_priority( expr , expr )		/* first expr refers to a pid */

expr	: any_expr
	| '(' expr ')'
	| expr andor expr
	| chanpoll '(' varref ')'	/* may not be negated */

chanpoll: FULL | EMPTY | NFULL | NEMPTY

string	: '"' [ any_ascii_char ] * '"'

uname	: name

name	: alpha [ alpha | number ] *

const	: TRUE | FALSE | SKIP | number [ number ] *

alpha	: 'a' | 'b' | 'c' | 'd' | 'e' | 'f' | 'g' | 'h' | 'i' | 'j'
	| 'k' | 'l' | 'm' | 'n' | 'o' | 'p' | 'q' | 'r' | 's' | 't'
	| 'u' | 'v' | 'w' | 'x' | 'y' | 'z'
	| 'A' | 'B' | 'C' | 'D' | 'E' | 'F' | 'G' | 'H' | 'I' | 'J'
	| 'K' | 'L' | 'M' | 'N' | 'O' | 'P' | 'Q' | 'R' | 'S' | 'T'
	| 'U' | 'V' | 'W' | 'X' | 'Y' | 'Z'
	| '_'

number	: '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'

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(Page Updated: 10 May 2012)