gistfile1.txt

--
-- apsh(1) interpreter specification in LBNF notation.


----------------------------------
-- The core statement language. --
----------------------------------

Prog.   Program  ::= [Function]    ;
Fun.    Function ::= Stm Exp Block ;
Block.  Decl     ::= [Decl]        ;

--------------
-- Comments --
--------------
comment "!!"       ;
comment "<" ">"    ;

----------------
-- Terminator --
----------------
terminator Function "!"            ;
terminator Stm      ""             ;
separator  Decl     ";"            ;

---------------
-- Functions --
---------------
Dns. Fun   ::= "dns" mode DnsRules ;

-- We now want to have some syntactic sugar. Note that the labels for
-- these rule all start with a lowercase letter, indicating that they
-- correspond to defined functions rather than nodes in the abstract
-- syntax tree.
-- help.          Stm ::= "show" Stm "!" ;
-- hostname.      Stm ::= "hostname" Ident "!" ;

-- Functions are defined using the 'define' keyword. Definitions have
-- the form 'define f x1 .. xn = e' where e is an expression on applicative
-- form using labels, other defined functions, lists and literals.
define dns m b        = Dns m b    ;

-----------------
-- Expressions --
-----------------
mode.          Exp      ::= ("enable" | "disable" | "reload" | "rules");

--------------------
-- Declaratations --
--------------------
DnsRules.       Block ::= [DnsDomain ";" DnsNS]       ;

DnsDomain.     Decl  ::= "search" Ident               ;
DnsNS.         Decl  ::= "nameserver" Ident ";" DnsNS ;

------------
-- Tokens --
------------
token Hexadecimal '0' ('x'|'X') (digit | ["abcdef"] | ["ABCDEF"])+ ;

hexadec.       Constant ::= Hexadecimal ;
int.           Constant ::= Integer     ;