%{
/*
 * XPathParser.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU JAXP, a library.
 *
 * GNU JAXP is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * GNU JAXP is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version. 
 */

package gnu.xml.xpath;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import javax.xml.namespace.NamespaceContext;
import javax.xml.namespace.QName;
import javax.xml.xpath.XPathFunctionResolver;
import javax.xml.xpath.XPathVariableResolver;
import org.w3c.dom.Node;

/**
 * An XPath 1.0 parser.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
public class XPathParser
{

  NamespaceContext namespaceContext;
  XPathVariableResolver variableResolver;
  XPathFunctionResolver functionResolver;

  QName getQName(String name)
  {
    QName qName = QName.valueOf(name);
    if (namespaceContext != null)
      {
        String prefix = qName.getPrefix();
        String uri = qName.getNamespaceURI();
        if (prefix != null && (uri == null || uri.length() == 0))
          {
            uri = namespaceContext.getNamespaceURI(prefix);
            String localName = qName.getLocalPart();
            qName = new QName(uri, localName, prefix);
          }
      }
    return qName;
  }

  Expr lookupFunction(String name, List args)
  {
    int arity = args.size();
    if ("position".equals(name) && arity == 0)
      {
        return new PositionFunction();
      }
    else if ("last".equals(name) && arity == 0)
      {
        return new LastFunction();
      }
    else if ("string".equals(name) && (arity == 1 || arity == 0))
      {
        return new StringFunction(args);
      }
    else if ("number".equals(name) && (arity == 1 || arity == 0))
      {
        return new NumberFunction(args);
      }
    else if ("boolean".equals(name) && arity == 1)
      {
        return new BooleanFunction(args);
      }
    else if ("count".equals(name) && arity == 1)
      {
        return new CountFunction(args);
      }
    else if ("not".equals(name) && arity == 1)
      {
        return new NotFunction(args);
      }
    else if ("id".equals(name) && arity == 1)
      {
        return new IdFunction(args);
      }
    else if ("concat".equals(name) && arity > 1)
      {
        return new ConcatFunction(args);
      }
    else if ("true".equals(name) && arity == 0)
      {
        return new TrueFunction();
      }
    else if ("false".equals(name) && arity == 0)
      {
        return new FalseFunction();
      }
    else if ("name".equals(name) && (arity == 1 || arity == 0))
      {
        return new NameFunction(args);
      }
    else if ("local-name".equals(name) && (arity == 1 || arity == 0))
      {
        return new LocalNameFunction(args);
      }
    else if ("namespace-uri".equals(name) && (arity == 1 || arity == 0))
      {
        return new NamespaceUriFunction(args);
      }
    else if ("starts-with".equals(name) && arity == 2)
      {
        return new StartsWithFunction(args);
      }
    else if ("contains".equals(name) && arity == 2)
      {
        return new ContainsFunction(args);
      }
    else if ("string-length".equals(name) && (arity == 1 || arity == 0))
      {
        return new StringLengthFunction(args);
      }
    else if ("translate".equals(name) && arity == 3)
      {
        return new TranslateFunction(args);
      }
    else if ("normalize-space".equals(name) && (arity == 1 || arity == 0))
      {
        return new NormalizeSpaceFunction(args);
      }
    else if ("substring".equals(name) && (arity == 2 || arity == 3))
      {
        return new SubstringFunction(args);
      }
    else if ("substring-before".equals(name) && arity == 2)
      {
        return new SubstringBeforeFunction(args);
      }
    else if ("substring-after".equals(name) && arity == 2)
      {
        return new SubstringAfterFunction(args);
      }
    else if ("lang".equals(name) && arity == 1)
      {
        return new LangFunction(args);
      }
    else if ("sum".equals(name) && arity == 1)
      {
        return new SumFunction(args);
      }
    else if ("floor".equals(name) && arity == 1)
      {
        return new FloorFunction(args);
      }
    else if ("ceiling".equals(name) && arity == 1)
      {
        return new CeilingFunction(args);
      }
    else if ("round".equals(name) && arity == 1)
      {
        return new RoundFunction(args);
      }
    else if (functionResolver != null)
      {
        QName qName = QName.valueOf(name);
        Object function = functionResolver.resolveFunction(qName, arity);
        if (function != null &&
            function instanceof Function &&
            function instanceof Expr)
          {
            Function f = (Function) function;
            f.setArguments(args);
            return (Expr) function;
          }
      }
    return new FunctionCall(functionResolver, name, args);
  }

%}

%token LITERAL
%token DIGITS
%token NAME

%token LP // '('
%token RP // ')'
%token LB // '['
%token RB // ']'
%token COMMA // ','
%token PIPE // '|'
%token SLASH // '/'
%token DOUBLE_SLASH // '//'
%token EQ // '='
%token NE // '!='
%token GT // '>'
%token LT // '<'
%token GTE // '>='
%token LTE // '<='
%token PLUS // '+'
%token MINUS // '-'
%token AT // '@'
%token STAR // '*'
%token DOLLAR // '$'
%token COLON // ':'
%token DOUBLE_COLON // '::'
%token DOT // '.'
%token DOUBLE_DOT // '..'

%token ANCESTOR
%token ANCESTOR_OR_SELF
%token ATTRIBUTE
%token CHILD
%token DESCENDANT
%token DESCENDANT_OR_SELF
%token FOLLOWING
%token FOLLOWING_SIBLING
%token NAMESPACE
%token PARENT
%token PRECEDING
%token PRECEDING_SIBLING
%token SELF
%token DIV
%token MOD
%token OR
%token AND
%token COMMENT
%token PROCESSING_INSTRUCTION
%token TEXT
%token NODE

%right UNARY

%start expr

%%

expr:
  or_expr
  ;

location_path:
  relative_location_path
  | absolute_location_path
  ;

absolute_location_path:
  SLASH
    {
      $$ = new Root();
    }
  | SLASH relative_location_path
    {
      Steps steps;
      if ($2 instanceof Steps)
        {
          steps = (Steps) $2;
        }
      else
        {
          steps = new Steps();
          steps.path.addFirst($2);
        }
      steps.path.addFirst(new Root());
      $$ = steps;
      //$$ = new Step(new Root(), (Path) $2);
    }
  | DOUBLE_SLASH relative_location_path
    {
      Test nt = new NodeTypeTest((short) 0);
      Selector s = new Selector(Selector.DESCENDANT_OR_SELF,
                                Collections.singletonList (nt));
      Steps steps;
      if ($2 instanceof Steps)
        {
          steps = (Steps) $2;
        }
      else
        {
          steps = new Steps();
          steps.path.addFirst($2);
        }
      steps.path.addFirst(s);
      steps.path.addFirst(new Root());
      $$ = steps;
      //Step step = new Step(s, (Path) $2);
      //$$ = new Step(new Root(), step);
    }
  ;

relative_location_path:
  step
  | relative_location_path SLASH step
    {
      Steps steps;
      if ($1 instanceof Steps)
        {
          steps = (Steps) $1;
        }
      else
        {
          steps = new Steps();
          steps.path.addFirst($1);
        }
      steps.path.addLast($3);
      $$ = steps;
      //$$ = new Step((Expr) $1, (Path) $3);
    }
  | relative_location_path DOUBLE_SLASH step
    {
      Test nt = new NodeTypeTest((short) 0);
      Selector s = new Selector(Selector.DESCENDANT_OR_SELF,
                                Collections.singletonList (nt));
      Steps steps;
      if ($1 instanceof Steps)
        {
          steps = (Steps) $1;
        }
      else
        {
          steps = new Steps();
          steps.path.addFirst($1);
        }
      steps.path.addLast(s);
      steps.path.addLast($3);
      $$ = steps;
      //Step step = new Step(s, (Path) $3);
      //$$ = new Step((Expr) $1, step);
    }
  ;

step:
  step_node_test
    {
      $$ = new Selector (Selector.CHILD, (List) $1);
    }
  | AT step_node_test
    {
      $$ = new Selector (Selector.ATTRIBUTE, (List) $2);
    }
  | axis_name DOUBLE_COLON step_node_test
    {
      $$ = new Selector (((Integer) $1).intValue (), (List) $3);
    }
  | DOT
    {
      $$ = new Selector (Selector.SELF, Collections.EMPTY_LIST);
    }
  | DOUBLE_DOT
    {
      $$ = new Selector (Selector.PARENT, Collections.EMPTY_LIST);
    }
  ;

step_node_test:
  node_test
    {
      List list = new ArrayList();
      list.add($1);
      $$ = list;
    }
  | step_node_test predicate
    {
      List list = (List)$1;
      list.add($2);
      $$ = list;
    }
  ;

/*predicate_list:
  predicate
    {
      List list = new ArrayList ();
      list.add ($1);
      $$ = list;
    }
  | predicate predicate_list
    {
      List list = (List) $3;
      list.add (0, $1);
      $$ = list;
    }
  ;*/

axis_name:
  ANCESTOR
    {
      $$ = new Integer(Selector.ANCESTOR);
    }
  | ANCESTOR_OR_SELF
    {
      $$ = new Integer(Selector.ANCESTOR_OR_SELF);
    }
  | ATTRIBUTE
    {
      $$ = new Integer(Selector.ATTRIBUTE);
    }
  | CHILD
    {
      $$ = new Integer(Selector.CHILD);
    }
  | DESCENDANT
    {
      $$ = new Integer(Selector.DESCENDANT);
    }
  | DESCENDANT_OR_SELF
    {
      $$ = new Integer(Selector.DESCENDANT_OR_SELF);
    }
  | FOLLOWING
    {
      $$ = new Integer(Selector.FOLLOWING);
    }
  | FOLLOWING_SIBLING
    {
      $$ = new Integer(Selector.FOLLOWING_SIBLING);
    }
  | NAMESPACE
    {
      $$ = new Integer(Selector.NAMESPACE);
    }
  | PARENT
    {
      $$ = new Integer(Selector.PARENT);
    }
  | PRECEDING
    {
      $$ = new Integer(Selector.PRECEDING);
    }
  | PRECEDING_SIBLING
    {
      $$ = new Integer(Selector.PRECEDING_SIBLING);
    }
  | SELF
    {
      $$ = new Integer(Selector.SELF);
    }
  ;

node_test:
  name_test
  /*| PROCESSING_INSTRUCTION LP LITERAL RP*/
  | PROCESSING_INSTRUCTION LITERAL RP
    {
      $$ = new NodeTypeTest(Node.PROCESSING_INSTRUCTION_NODE, (String) $2);
    }
  /*| node_type LP RP*/
  | node_type RP
    {
      $$ = new NodeTypeTest(((Short) $1).shortValue());
    }
  ;

predicate:
  LB expr RB
    {
      $$ = new Predicate((Expr) $2);
    }
  ;

primary_expr:
  variable_reference
  | LP expr RP
    {
      $$ = new ParenthesizedExpr((Expr) $2);
    }
  | LITERAL
    {
      $$ = new Constant($1);
    }
  | number
    {
      $$ = new Constant($1);
    }
  | function_call
  ;

function_call:
  function_name LP RP
    {
      $$ = lookupFunction((String) $1, Collections.EMPTY_LIST);
    }
  | function_name LP argument_list RP
    {
      $$ = lookupFunction((String) $1, (List) $3);
    }
  ;

argument_list:
  expr
    {
      List list = new ArrayList();
      list.add($1);
      $$ = list;
    }
  | expr COMMA argument_list
    {
      List list = (List) $3;
      list.add(0, $1);
      $$ = list;
    }
  ;

union_expr:
  path_expr
  | union_expr PIPE path_expr
    {
      $$ = new UnionExpr((Expr) $1, (Expr) $3);
    }
  ;

path_expr:
  location_path
  | filter_expr
  | filter_expr SLASH relative_location_path
    {
      Steps steps;
      if ($3 instanceof Steps)
        {
          steps = (Steps) $3;
        }
      else
        {
          steps = new Steps();
          steps.path.addFirst($3);
        }
      steps.path.addFirst($1);
      $$ = steps;
      //$$ = new Step ((Expr) $1, (Path) $3);
    }
  | filter_expr DOUBLE_SLASH relative_location_path
    {
      Test nt = new NodeTypeTest((short) 0);
      Selector s = new Selector(Selector.DESCENDANT_OR_SELF,
                                Collections.singletonList(nt));
      Steps steps;
      if ($3 instanceof Steps)
        {
          steps = (Steps) $3;
        }
      else
        {
          steps = new Steps();
          steps.path.addFirst($3);
        }
      steps.path.addFirst(s);
      steps.path.addFirst($1);
      $$ = steps;
      //Step step = new Step (s, (Path) $3);
      //$$ = new Step ((Expr) $1, step);
    }
  ;

filter_expr:
  primary_expr
  | filter_expr predicate
    {
      Predicate filter = (Predicate) $2;
      Selector s = new Selector(Selector.SELF,
                                Collections.singletonList(filter));
      Steps steps;
      if ($1 instanceof Steps)
        {
          steps = (Steps) $1;
        }
      else
        {
          steps = new Steps();
          steps.path.addFirst($1);
        }
      steps.path.addLast(s);
      $$ = steps;
      //$$ = new Step ((Expr) $1, s);
    }
  ;

or_expr:
  and_expr
  | or_expr OR and_expr
    {
      $$ = new OrExpr((Expr) $1, (Expr) $3);
    }
  ;

and_expr:
  equality_expr
  | and_expr AND equality_expr
    {
      $$ = new AndExpr((Expr) $1, (Expr) $3);
    }
  ;

equality_expr:
  relational_expr
  | equality_expr EQ relational_expr
    {
      $$ = new EqualityExpr((Expr) $1, (Expr) $3, false);
    }
  | equality_expr NE relational_expr
    {
      $$ = new EqualityExpr((Expr) $1, (Expr) $3, true);
    }
  ;

relational_expr:
  additive_expr
  | relational_expr LT additive_expr
    {
      $$ = new RelationalExpr((Expr) $1, (Expr) $3, true, false);
    }
  | relational_expr GT additive_expr
    {
      $$ = new RelationalExpr((Expr) $1, (Expr) $3, false, false);
    }
  | relational_expr LTE additive_expr
    {
      $$ = new RelationalExpr((Expr) $1, (Expr) $3, true, true);
    }
  | relational_expr GTE additive_expr
    {
      $$ = new RelationalExpr((Expr) $1, (Expr) $3, false, true);
    }
  ;

additive_expr:
  multiplicative_expr
  | additive_expr PLUS multiplicative_expr
    {
      $$ = new ArithmeticExpr((Expr) $1, (Expr) $3, ArithmeticExpr.ADD);
    }
  | additive_expr MINUS multiplicative_expr
    {
      $$ = new ArithmeticExpr((Expr) $1, (Expr) $3, ArithmeticExpr.SUBTRACT);
    }
  ;

multiplicative_expr:
  unary_expr
  | multiplicative_expr STAR unary_expr
    {
      $$ = new ArithmeticExpr((Expr) $1, (Expr) $3, ArithmeticExpr.MULTIPLY);
    }
  | multiplicative_expr DIV unary_expr
    {
      $$ = new ArithmeticExpr((Expr) $1, (Expr) $3, ArithmeticExpr.DIVIDE);
    }
  | multiplicative_expr MOD unary_expr
    {
      $$ = new ArithmeticExpr((Expr) $1, (Expr) $3, ArithmeticExpr.MODULO);
    }
  ;

unary_expr:
  union_expr
  | MINUS unary_expr %prec UNARY
    {
      $$ = new NegativeExpr((Expr) $2);
    }
  ;

number:
  DIGITS
    {
      $$ = new Double((String) $1 + ".0");
    }
  | DIGITS DOT
    {
      $$ = new Double((String) $1 + ".0");
    }
  | DIGITS DOT DIGITS
    {
      $$ = new Double((String) $1 + "." + (String) $3);
    }
  | DOT DIGITS
    {
      $$ = new Double("0." + (String) $2);
    }
  ;

function_name:
  qname
/*  | node_type
    {
      switch (((Short) $1).shortValue ())
        {
        case Node.COMMENT_NODE:
          $$ = "comment";
          break;
        case Node.TEXT_NODE:
          $$ = "text";
          break;
        case Node.PROCESSING_INSTRUCTION_NODE:
          $$ = "processing-instruction";
          break;
        default:
          $$ = "node";
          break;
        }
    }*/
  ;

variable_reference:
  DOLLAR qname
    {
      String name = (String) $2;
      $$ = new VariableReference(variableResolver, getQName(name));
    }
  ;

name_test:
  STAR
    {
      $$ = new NameTest(null, true, true);
    }
  | NAME COLON STAR
    {
      QName qName = getQName((String) $1);
      $$ = new NameTest(qName, true, false);
    }
  | qname
    {
      QName qName = getQName((String) $1);
      $$ = new NameTest(qName, false, false);
    }
  ;

qname:
  NAME
  | NAME COLON NAME
    {
      $$ = (String) $1 + ':' + (String) $3;
    }
  ;

node_type:
  COMMENT
    {
      $$ = new Short(Node.COMMENT_NODE);
    }
  | TEXT
    {
      $$ = new Short(Node.TEXT_NODE);
    }
  | PROCESSING_INSTRUCTION
    {
      $$ = new Short(Node.PROCESSING_INSTRUCTION_NODE);
    }
  | NODE
    {
      $$ = new Short((short) 0);
    }
  ;

%%

}