Attempt at a basic STRIPS PDDL grammar parser for pegjs.org. To use, visit http://pegjs.org/online and paste the below grammar into the left-side window. In the right-side window, paste a PDDL domain file, such as https://spark-public.s3.amazonaws.com/aiplan/resources/random-domain.txt. The output will display in the Output panel.

domain-grammar.txt

/*STRIPS PDDL parser for http://pegjs.org/online
For example of parsing this grammar, see https://gist.github.com/primaryobjects/1d2f7ee668b62ca99095
Example PDDL domain to parse:

(define (domain random-domain)
  (:requirements :strips)
  (:action op1
    :parameters (?x1 ?x2 ?x3)
    :precondition (and (S ?x1 ?x2) (R ?x3 ?x1))
    :effect (and (S ?x2 ?x1) (S ?x1 ?x3) (not (R ?x3 ?x1))))
  (:action op2
    :parameters (?x1 ?x2 ?x3)
    :precondition (and (S ?x3 ?x1) (R ?x2 ?x2))
    :effect (and (S ?x1 ?x3) (not (S ?x3 ?x1)))))
*/

program   = result:domain { return result; }
 
domain = space* delimiter* "define" space* delimiter* "domain" space* domainName:word delimiter* req:req actions:action*
{
  var reqs = '';
  for (var i in req) {
     reqs += req[i] + ', ';
  }
 
  return { domain: domainName.join('').replace(/[,:?]/g, ''), requirements: req, actions: actions };
}
 
req = ":requirements" req:reqType* delimiter*
{
  var result = [];
  for (var i in req) {
     result.push(req[i]);
  }
 
  return result;
}
 
reqType = space* ":" req:word
{ return req.join('').replace(/[,:?]/g, ''); }
 
action = ":action" space* operationName:word parameters:parameters precondition:precondition effect:effect
{ return { action: operationName.join('').replace(/[,:?]/g, ''), parameters: parameters, precondition: precondition, effect: effect }; }
 
logic = operation:logicOp* delimiter* action:word space* params:parameter* delimiter*
{ return { operation: operation.join('').replace(/[,:? ]/g, ''), action: action.join('').replace(/[,:? ]/g, ''), parameters: params }; }
 
boolean   = "#t" / "#f"
integer   = [1-9] [0-9]*
string    = "\"" ("\\" . / [^"])* "\""
word      = word:([a-zA-Z0-9\-]+) { return word; }
symbol    = (!delimiter .)+
space     = [\n\r\t ]
paren     = "(" / ")"
logicOp   = "and" / "not"
delimiter = paren / space
 
parameters = space* ":parameters" delimiter+ params:parameter+ delimiter space*
{ return params; }
 
parameter = "?" param:word space*
{ return param.join('').replace(/[,:? ]/g, ''); }
 
precondition = space* ":precondition" delimiter+ logic:logic+
{ return logic; }
 
effect = space* ":effect" delimiter+ logic:logic+
{ return logic; }