PEG for LiquidPlanner Ranged Estimate

estimate.peg

// Just playing around...
// http://pegjs.majda.cz/online

start
  = '[' _ est:estimate _ ']' { return est; }
  / est:estimate { return est; }

estimate
  = low:duration _ '-' _ high:duration {return [low, high]}
  / fixed:duration { return [fixed, fixed]; }

duration
  = n:number _ u:unit { return [n,u] }
  /  n:number { return [n,'h'] }

unit
  = [hdm]

number "number"
  = int_:int frac:frac exp:exp _ { return parseFloat(int_ + frac + exp); }
  / int_:int frac:frac _         { return parseFloat(int_ + frac);       }
  / int_:int exp:exp _           { return parseFloat(int_ + exp);        }
  / int_:int _                   { return parseFloat(int_);              }

int
  = digit19:digit19 digits:digits     { return digit19 + digits;       }
  / digit:digit
  / "-" digit19:digit19 digits:digits { return "-" + digit19 + digits; }
  / "-" digit:digit                   { return "-" + digit;            }

frac
  = "." digits:digits { return "." + digits; }

exp
  = e:e digits:digits { return e + digits; }

digits
  = digits:digit+ { return digits.join(""); }

e
  = e:[eE] sign:[+-]? { return e + sign; }

/*
 * The following rules are not present in the original JSON gramar, but they are
 * assumed to exist implicitly.
 *
 * FIXME: Define them according to ECMA-262, 5th ed.
 */

digit
  = [0-9]

digit19
  = [1-9]

hexDigit
  = [0-9a-fA-F]

/* ===== Whitespace ===== */

_ "whitespace"
  = whitespace*

// Whitespace is undefined in the original JSON grammar, so I assume a simple
// conventional definition consistent with ECMA-262, 5th ed.
whitespace
  = [ \t\n\r]