solr/core/src/java/org/apache/solr/search/FunctionQParser.java - lucene-solr - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.solr.search;

 import java.util.ArrayList;
 import java.util.List;

 import org.apache.lucene.queries.function.FunctionQuery;
 import org.apache.lucene.queries.function.ValueSource;
 import org.apache.lucene.queries.function.valuesource.ConstValueSource;
 import org.apache.lucene.queries.function.valuesource.DoubleConstValueSource;
 import org.apache.lucene.queries.function.valuesource.LiteralValueSource;
 import org.apache.lucene.queries.function.valuesource.QueryValueSource;
 import org.apache.lucene.queries.function.valuesource.VectorValueSource;
 import org.apache.lucene.search.Query;
 import org.apache.solr.common.params.ModifiableSolrParams;
 import org.apache.solr.common.params.SolrParams;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.schema.SchemaField;
 import org.apache.solr.search.facet.AggValueSource;
 import org.apache.solr.search.function.FieldNameValueSource;

 public class FunctionQParser extends QParser {

   public static final int FLAG_CONSUME_DELIMITER = 0x01;  // consume delimiter after parsing arg
   public static final int FLAG_IS_AGG = 0x02;
   public static final int FLAG_USE_FIELDNAME_SOURCE = 0x04; // When a field name is encountered, use the placeholder FieldNameValueSource instead of resolving to a real ValueSource
   public static final int FLAG_DEFAULT = FLAG_CONSUME_DELIMITER;

   /** @lucene.internal */
   public StrParser sp;
   boolean parseMultipleSources = true;
   boolean parseToEnd = true;

   public FunctionQParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) {
     super(qstr, localParams, params, req);
     setString(qstr);
   }

   @Override
   public void setString(String s) {
     super.setString(s);
     if (s != null) {
       sp = new StrParser( s );
     }
   }

   public void setParseMultipleSources(boolean parseMultipleSources) {
     this.parseMultipleSources = parseMultipleSources;
   }

   /** parse multiple comma separated value sources */
   public boolean getParseMultipleSources() {
     return parseMultipleSources;
   }

   public void setParseToEnd(boolean parseToEnd) {
     this.parseToEnd = parseToEnd;
   }

   /** throw exception if there is extra stuff at the end of the parsed valuesource(s). */
   public boolean getParseToEnd() {
     return parseMultipleSources;
   }

   @Override
   public Query parse() throws SyntaxError {
     ValueSource vs = null;
     List<ValueSource> lst = null;

     for(;;) {
       ValueSource valsource = parseValueSource(FLAG_DEFAULT & ~FLAG_CONSUME_DELIMITER);
       sp.eatws();
       if (!parseMultipleSources) {
         vs = valsource;
         break;
       } else {
         if (lst != null) {
           lst.add(valsource);
         } else {
           vs = valsource;
         }
       }

       // check if there is a "," separator
       if (sp.peek() != ',') break;

       consumeArgumentDelimiter();

       if (lst == null) {
         lst = new ArrayList<>(2);
         lst.add(valsource);
       }
     }

     if (parseToEnd && sp.pos < sp.end) {
       throw new SyntaxError("Unexpected text after function: " + sp.val.substring(sp.pos, sp.end));
     }

     if (lst != null) {
       vs = new VectorValueSource(lst);
     }

     return new FunctionQuery(vs);
   }

   /**
    * Are there more arguments in the argument list being parsed?
    *
    * @return whether more args exist
    */
   public boolean hasMoreArguments() throws SyntaxError {
     int ch = sp.peek();
     /* determine whether the function is ending with a paren or end of str */
     return (! (ch == 0 || ch == ')') );
   }

   /*
    * TODO: Doc
    */
   public String parseId() throws SyntaxError {
     String value = parseArg();
     if (argWasQuoted()) {
       throw new SyntaxError("Expected identifier instead of quoted string:" + value);
     } else if (value == null) {
       throw new SyntaxError("Expected identifier instead of 'null' for function "  + sp);
     }
     return value;
   }

   /**
    * Parse a float.
    *
    * @return Float
    */
   public Float parseFloat() throws SyntaxError {
     String str = parseArg();
     if (argWasQuoted()) throw new SyntaxError("Expected float instead of quoted string:" + str);
     try {
       return Float.parseFloat(str);
     } catch (NumberFormatException | NullPointerException e) {
       throw new SyntaxError("Expected float instead of '" + str + "' for function "  + sp);
     }
   }

   /**
    * Parse a Double
    * @return double
    */
   public double parseDouble() throws SyntaxError {
     String str = parseArg();
     if (argWasQuoted()) throw new SyntaxError("Expected double instead of quoted string:" + str);
     try {
       return Double.parseDouble(str);
     } catch (NumberFormatException | NullPointerException e) {
       throw new SyntaxError("Expected double instead of '" + str + "' for function " + sp);
     }
   }

   /**
    * Parse an integer
    * @return An int
    */
   public int parseInt() throws SyntaxError {
     String str = parseArg();
     if (argWasQuoted()) throw new SyntaxError("Expected integer instead of quoted string:" + str);
     try {
       return Integer.parseInt(str);
     } catch (NumberFormatException | NullPointerException e) {
       throw new SyntaxError("Expected integer instead of '" + str + "' for function "  + sp);
     }
   }


   private boolean argWasQuoted;
   public boolean argWasQuoted() {
     return argWasQuoted;
   }

   public String parseArg() throws SyntaxError {
     argWasQuoted = false;

     sp.eatws();
     char ch = sp.peek();
     String val = null;
     switch (ch) {
       case ')': return null;
       case '$':
         sp.pos++;
         String param = sp.getId();
         val = getParam(param);
         break;
       case '\'':
       case '"':
         val = sp.getQuotedString();
         argWasQuoted = true;
         break;
       default:
         // read unquoted literal ended by whitespace ',' or ')'
         // there is no escaping.
         int valStart = sp.pos;
         for (;;) {
           if (sp.pos >= sp.end) {
             throw new SyntaxError("Missing end to unquoted value starting at " + valStart + " str='" + sp.val +"'");
           }
           char c = sp.val.charAt(sp.pos);
           if (c==')' || c==',' || Character.isWhitespace(c)) {
             val = sp.val.substring(valStart, sp.pos);
             break;
           }
           sp.pos++;
         }
     }

     sp.eatws();
     consumeArgumentDelimiter();
     return val;
   }


   /**
    * Parse a list of ValueSource.  Must be the final set of arguments
    * to a ValueSource.
    *
    * @return List&lt;ValueSource&gt;
    */
   public List<ValueSource> parseValueSourceList() throws SyntaxError {
     return parseValueSourceList(FLAG_DEFAULT | FLAG_CONSUME_DELIMITER);
   }

   /**
    * Parse a list of ValueSource.  Must be the final set of arguments
    * to a ValueSource.
    *
    * @param flags - customize parsing behavior
    *
    * @return List&lt;ValueSource&gt;
    */
   public List<ValueSource> parseValueSourceList(int flags) throws SyntaxError {
     List<ValueSource> sources = new ArrayList<>(3);
     while (hasMoreArguments()) {
       sources.add(parseValueSource(flags));
     }
     return sources;
   }

   /**
    * Parse an individual ValueSource.
    */
   public ValueSource parseValueSource() throws SyntaxError {
     /* consume the delimiter afterward for an external call to parseValueSource */
     return parseValueSource(FLAG_DEFAULT | FLAG_CONSUME_DELIMITER);
   }

   /*
    * TODO: Doc
    */
   public Query parseNestedQuery() throws SyntaxError {
     Query nestedQuery;

     if (sp.opt("$")) {
       String param = sp.getId();
       String qstr = getParam(param);
       qstr = qstr==null ? "" : qstr;
       nestedQuery = subQuery(qstr, null).getQuery();

       // nestedQuery would be null when de-referenced query value is not specified
       // Ex: query($qq) in request with no qq param specified
       if (nestedQuery == null) {
         throw new SyntaxError("Missing param " + param + " while parsing function '" + sp.val + "'");
       }
     }
     else {
       int start = sp.pos;
       String v = sp.val;

       String qs = v;
       ModifiableSolrParams nestedLocalParams = new ModifiableSolrParams();
       int end = QueryParsing.parseLocalParams(qs, start, nestedLocalParams, getParams());

       QParser sub;

       if (end>start) {
         if (nestedLocalParams.get(QueryParsing.V) != null) {
           // value specified directly in local params... so the end of the
           // query should be the end of the local params.
           sub = subQuery(qs.substring(start, end), null);
         } else {
           // value here is *after* the local params... ask the parser.
           sub = subQuery(qs, null);
           // int subEnd = sub.findEnd(')');
           // TODO.. implement functions to find the end of a nested query
           throw new SyntaxError("Nested local params must have value in v parameter.  got '" + qs + "'");
         }
       } else {
         throw new SyntaxError("Nested function query must use $param or {!v=value} forms. got '" + qs + "'");
       }

       sp.pos += end-start;  // advance past nested query
       nestedQuery = sub.getQuery();
       // handling null check on nestedQuery separately, so that proper error can be returned
       // one case this would be possible when v is specified but v's value is empty or has only spaces
       if (nestedQuery == null) {
         throw new SyntaxError("Nested function query returned null for '" + sp.val + "'");
       }
     }
     consumeArgumentDelimiter();

     return nestedQuery;
   }

   /**
    * Parse an individual value source.
    *
    * @param doConsumeDelimiter whether to consume a delimiter following the ValueSource
    */
    protected ValueSource parseValueSource(boolean doConsumeDelimiter) throws SyntaxError {
      return parseValueSource( doConsumeDelimiter ? (FLAG_DEFAULT | FLAG_CONSUME_DELIMITER) : (FLAG_DEFAULT & ~FLAG_CONSUME_DELIMITER) );
    }

    protected ValueSource parseValueSource(int flags) throws SyntaxError {
     ValueSource valueSource;

     int ch = sp.peek();
     if (ch>='0' && ch<='9'  || ch=='.' || ch=='+' || ch=='-') {
       Number num = sp.getNumber();
       if (num instanceof Long) {
         valueSource = new LongConstValueSource(num.longValue());
       } else if (num instanceof Double) {
         valueSource = new DoubleConstValueSource(num.doubleValue());
       } else {
         // shouldn't happen
         valueSource = new ConstValueSource(num.floatValue());
       }
     } else if (ch == '"' || ch == '\''){
       valueSource = new LiteralValueSource(sp.getQuotedString());
     } else if (ch == '$') {
       sp.pos++;
       String param = sp.getId();
       String val = getParam(param);
       if (val == null) {
         throw new SyntaxError("Missing param " + param + " while parsing function '" + sp.val + "'");
       }

       if ((flags & FLAG_USE_FIELDNAME_SOURCE) != 0 && req.getSchema().getFieldOrNull(val) != null) {
         // Don't try to create a ValueSource for the field, just use a placeholder.
         // this handles the case like x=myfunc($qq)&qq=something
         valueSource = new FieldNameValueSource(val);
       } else {
         QParser subParser = subQuery(val, "func");
         if (subParser instanceof FunctionQParser) {
           ((FunctionQParser) subParser).setParseMultipleSources(true);
         }
         Query subQuery = subParser.getQuery();
         if (subQuery == null) {
           valueSource = new ConstValueSource(0.0f);
         } else if (subQuery instanceof FunctionQuery) {
           valueSource = ((FunctionQuery) subQuery).getValueSource();
         } else {
           valueSource = new QueryValueSource(subQuery, 0.0f);
         }
       }

       /***
        // dereference *simple* argument (i.e., can't currently be a function)
        // In the future we could support full function dereferencing via a stack of ValueSource (or StringParser) objects
       ch = val.length()==0 ? '\0' : val.charAt(0);

       if (ch>='0' && ch<='9'  || ch=='.' || ch=='+' || ch=='-') {
         StrParser sp = new StrParser(val);
         Number num = sp.getNumber();
         if (num instanceof Long) {
           valueSource = new LongConstValueSource(num.longValue());
         } else if (num instanceof Double) {
           valueSource = new DoubleConstValueSource(num.doubleValue());
         } else {
           // shouldn't happen
           valueSource = new ConstValueSource(num.floatValue());
         }
       } else if (ch == '"' || ch == '\'') {
         StrParser sp = new StrParser(val);
         val = sp.getQuotedString();
         valueSource = new LiteralValueSource(val);
       } else {
         if (val.length()==0) {
           valueSource = new LiteralValueSource(val);
         } else {
           String id = val;
           SchemaField f = req.getSchema().getField(id);
           valueSource = f.getType().getValueSource(f, this);
         }
       }
        ***/

     } else {

       String id = sp.getId();
       if (sp.opt("(")) {
         // a function... look it up.
         ValueSourceParser argParser = req.getCore().getValueSourceParser(id);
         if (argParser==null) {
           throw new SyntaxError("Unknown function " + id + " in FunctionQuery(" + sp + ")");
         }
         valueSource = argParser.parse(this);
         sp.expect(")");
       } else {
         if ("true".equals(id)) {
           valueSource = new BoolConstValueSource(true);
         } else if ("false".equals(id)) {
           valueSource = new BoolConstValueSource(false);
         } else {
           if ((flags & FLAG_USE_FIELDNAME_SOURCE) != 0) {
             // Don't try to create a ValueSource for the field, just use a placeholder.
             valueSource = new FieldNameValueSource(id);
           } else {
             SchemaField f = req.getSchema().getField(id);
             valueSource = f.getType().getValueSource(f, this);
           }
         }
       }

     }

     if ((flags & FLAG_CONSUME_DELIMITER) != 0) {
       consumeArgumentDelimiter();
     }

     return valueSource;
   }

   /** @lucene.experimental */
   public AggValueSource parseAgg(int flags) throws SyntaxError {
     String origId = sp.getId();
     AggValueSource vs = null;
     boolean hasParen;

     if ("agg".equals(origId)) {
       hasParen = sp.opt("(");
       vs = parseAgg(flags | FLAG_IS_AGG);
     } else {
       // parse as an aggregation...
       String id = origId.startsWith("agg_")? origId: "agg_" + origId;
       hasParen = sp.opt("(");

       ValueSourceParser argParser = req.getCore().getValueSourceParser(id);
       if (argParser == null) {
         argParser = req.getCore().getValueSourceParser(origId);
         if (argParser == null) {
           throw new SyntaxError("Unknown aggregation '" + origId + "' in input (" + sp + ")");
         } else {
           throw new SyntaxError("Expected multi-doc aggregation from '" +  origId +
               "' but got per-doc function in input (" + sp + ")");
         }
       }

       ValueSource vv = argParser.parse(this);
       if (!(vv instanceof AggValueSource)) {
         throw new SyntaxError("Expected multi-doc aggregation from '" + origId +
             "' but got (" + vv + ") in (" + sp + ")");
       }
       vs = (AggValueSource) vv;
     }

     if (hasParen) {
       sp.expect(")");
     }

     if ((flags & FLAG_CONSUME_DELIMITER) != 0) {
       consumeArgumentDelimiter();
     }

     return vs;
   }


   /**
    * Consume an argument delimiter (a comma) from the token stream.
    * Only consumes if more arguments should exist (no ending parens or end of string).
    *
    * @return whether a delimiter was consumed
    */
   protected boolean consumeArgumentDelimiter() throws SyntaxError {
     /* if a list of args is ending, don't expect the comma */
     if (hasMoreArguments()) {
       sp.expect(",");
       return true;
     }

     return false;
   }


 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.apache.solr.search;

	import java.util.ArrayList;
	import java.util.List;

	import org.apache.lucene.queries.function.FunctionQuery;
	import org.apache.lucene.queries.function.ValueSource;
	import org.apache.lucene.queries.function.valuesource.ConstValueSource;
	import org.apache.lucene.queries.function.valuesource.DoubleConstValueSource;
	import org.apache.lucene.queries.function.valuesource.LiteralValueSource;
	import org.apache.lucene.queries.function.valuesource.QueryValueSource;
	import org.apache.lucene.queries.function.valuesource.VectorValueSource;
	import org.apache.lucene.search.Query;
	import org.apache.solr.common.params.ModifiableSolrParams;
	import org.apache.solr.common.params.SolrParams;
	import org.apache.solr.request.SolrQueryRequest;
	import org.apache.solr.schema.SchemaField;
	import org.apache.solr.search.facet.AggValueSource;
	import org.apache.solr.search.function.FieldNameValueSource;

	public class FunctionQParser extends QParser {

	public static final int FLAG_CONSUME_DELIMITER = 0x01; // consume delimiter after parsing arg
	public static final int FLAG_IS_AGG = 0x02;
	public static final int FLAG_USE_FIELDNAME_SOURCE = 0x04; // When a field name is encountered, use the placeholder FieldNameValueSource instead of resolving to a real ValueSource
	public static final int FLAG_DEFAULT = FLAG_CONSUME_DELIMITER;

	/** @lucene.internal */
	public StrParser sp;
	boolean parseMultipleSources = true;
	boolean parseToEnd = true;

	public FunctionQParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) {
	super(qstr, localParams, params, req);
	setString(qstr);
	}

	@Override
	public void setString(String s) {
	super.setString(s);
	if (s != null) {
	sp = new StrParser( s );
	}
	}

	public void setParseMultipleSources(boolean parseMultipleSources) {
	this.parseMultipleSources = parseMultipleSources;
	}

	/** parse multiple comma separated value sources */
	public boolean getParseMultipleSources() {
	return parseMultipleSources;
	}

	public void setParseToEnd(boolean parseToEnd) {
	this.parseToEnd = parseToEnd;
	}

	/** throw exception if there is extra stuff at the end of the parsed valuesource(s). */
	public boolean getParseToEnd() {
	return parseMultipleSources;
	}

	@Override
	public Query parse() throws SyntaxError {
	ValueSource vs = null;
	List<ValueSource> lst = null;

	for(;;) {
	ValueSource valsource = parseValueSource(FLAG_DEFAULT & ~FLAG_CONSUME_DELIMITER);
	sp.eatws();
	if (!parseMultipleSources) {
	vs = valsource;
	break;
	} else {
	if (lst != null) {
	lst.add(valsource);
	} else {
	vs = valsource;
	}
	}

	// check if there is a "," separator
	if (sp.peek() != ',') break;

	consumeArgumentDelimiter();

	if (lst == null) {
	lst = new ArrayList<>(2);
	lst.add(valsource);
	}
	}

	if (parseToEnd && sp.pos < sp.end) {
	throw new SyntaxError("Unexpected text after function: " + sp.val.substring(sp.pos, sp.end));
	}

	if (lst != null) {
	vs = new VectorValueSource(lst);
	}

	return new FunctionQuery(vs);
	}

	/**
	* Are there more arguments in the argument list being parsed?
	*
	* @return whether more args exist
	*/
	public boolean hasMoreArguments() throws SyntaxError {
	int ch = sp.peek();
	/* determine whether the function is ending with a paren or end of str */
	return (! (ch == 0 \|\| ch == ')') );
	}

	/*
	* TODO: Doc
	*/
	public String parseId() throws SyntaxError {
	String value = parseArg();
	if (argWasQuoted()) {
	throw new SyntaxError("Expected identifier instead of quoted string:" + value);
	} else if (value == null) {
	throw new SyntaxError("Expected identifier instead of 'null' for function " + sp);
	}
	return value;
	}

	/**
	* Parse a float.
	*
	* @return Float
	*/
	public Float parseFloat() throws SyntaxError {
	String str = parseArg();
	if (argWasQuoted()) throw new SyntaxError("Expected float instead of quoted string:" + str);
	try {
	return Float.parseFloat(str);
	} catch (NumberFormatException \| NullPointerException e) {
	throw new SyntaxError("Expected float instead of '" + str + "' for function " + sp);
	}
	}

	/**
	* Parse a Double
	* @return double
	*/
	public double parseDouble() throws SyntaxError {
	String str = parseArg();
	if (argWasQuoted()) throw new SyntaxError("Expected double instead of quoted string:" + str);
	try {
	return Double.parseDouble(str);
	} catch (NumberFormatException \| NullPointerException e) {
	throw new SyntaxError("Expected double instead of '" + str + "' for function " + sp);
	}
	}

	/**
	* Parse an integer
	* @return An int
	*/
	public int parseInt() throws SyntaxError {
	String str = parseArg();
	if (argWasQuoted()) throw new SyntaxError("Expected integer instead of quoted string:" + str);
	try {
	return Integer.parseInt(str);
	} catch (NumberFormatException \| NullPointerException e) {
	throw new SyntaxError("Expected integer instead of '" + str + "' for function " + sp);
	}
	}


	private boolean argWasQuoted;
	public boolean argWasQuoted() {
	return argWasQuoted;
	}

	public String parseArg() throws SyntaxError {
	argWasQuoted = false;

	sp.eatws();
	char ch = sp.peek();
	String val = null;
	switch (ch) {
	case ')': return null;
	case '$':
	sp.pos++;
	String param = sp.getId();
	val = getParam(param);
	break;
	case '\'':
	case '"':
	val = sp.getQuotedString();
	argWasQuoted = true;
	break;
	default:
	// read unquoted literal ended by whitespace ',' or ')'
	// there is no escaping.
	int valStart = sp.pos;
	for (;;) {
	if (sp.pos >= sp.end) {
	throw new SyntaxError("Missing end to unquoted value starting at " + valStart + " str='" + sp.val +"'");
	}
	char c = sp.val.charAt(sp.pos);
	if (c==')' \|\| c==',' \|\| Character.isWhitespace(c)) {
	val = sp.val.substring(valStart, sp.pos);
	break;
	}
	sp.pos++;
	}
	}

	sp.eatws();
	consumeArgumentDelimiter();
	return val;
	}


	/**
	* Parse a list of ValueSource. Must be the final set of arguments
	* to a ValueSource.
	*
	* @return List<ValueSource>
	*/
	public List<ValueSource> parseValueSourceList() throws SyntaxError {
	return parseValueSourceList(FLAG_DEFAULT \| FLAG_CONSUME_DELIMITER);
	}

	/**
	* Parse a list of ValueSource. Must be the final set of arguments
	* to a ValueSource.
	*
	* @param flags - customize parsing behavior
	*
	* @return List<ValueSource>
	*/
	public List<ValueSource> parseValueSourceList(int flags) throws SyntaxError {
	List<ValueSource> sources = new ArrayList<>(3);
	while (hasMoreArguments()) {
	sources.add(parseValueSource(flags));
	}
	return sources;
	}

	/**
	* Parse an individual ValueSource.
	*/
	public ValueSource parseValueSource() throws SyntaxError {
	/* consume the delimiter afterward for an external call to parseValueSource */
	return parseValueSource(FLAG_DEFAULT \| FLAG_CONSUME_DELIMITER);
	}

	/*
	* TODO: Doc
	*/
	public Query parseNestedQuery() throws SyntaxError {
	Query nestedQuery;

	if (sp.opt("$")) {
	String param = sp.getId();
	String qstr = getParam(param);
	qstr = qstr==null ? "" : qstr;
	nestedQuery = subQuery(qstr, null).getQuery();

	// nestedQuery would be null when de-referenced query value is not specified
	// Ex: query($qq) in request with no qq param specified
	if (nestedQuery == null) {
	throw new SyntaxError("Missing param " + param + " while parsing function '" + sp.val + "'");
	}
	}
	else {
	int start = sp.pos;
	String v = sp.val;

	String qs = v;
	ModifiableSolrParams nestedLocalParams = new ModifiableSolrParams();
	int end = QueryParsing.parseLocalParams(qs, start, nestedLocalParams, getParams());

	QParser sub;

	if (end>start) {
	if (nestedLocalParams.get(QueryParsing.V) != null) {
	// value specified directly in local params... so the end of the
	// query should be the end of the local params.
	sub = subQuery(qs.substring(start, end), null);
	} else {
	// value here is after the local params... ask the parser.
	sub = subQuery(qs, null);
	// int subEnd = sub.findEnd(')');
	// TODO.. implement functions to find the end of a nested query
	throw new SyntaxError("Nested local params must have value in v parameter. got '" + qs + "'");
	}
	} else {
	throw new SyntaxError("Nested function query must use $param or {!v=value} forms. got '" + qs + "'");
	}

	sp.pos += end-start; // advance past nested query
	nestedQuery = sub.getQuery();
	// handling null check on nestedQuery separately, so that proper error can be returned
	// one case this would be possible when v is specified but v's value is empty or has only spaces
	if (nestedQuery == null) {
	throw new SyntaxError("Nested function query returned null for '" + sp.val + "'");
	}
	}
	consumeArgumentDelimiter();

	return nestedQuery;
	}

	/**
	* Parse an individual value source.
	*
	* @param doConsumeDelimiter whether to consume a delimiter following the ValueSource
	*/
	protected ValueSource parseValueSource(boolean doConsumeDelimiter) throws SyntaxError {
	return parseValueSource( doConsumeDelimiter ? (FLAG_DEFAULT \| FLAG_CONSUME_DELIMITER) : (FLAG_DEFAULT & ~FLAG_CONSUME_DELIMITER) );
	}

	protected ValueSource parseValueSource(int flags) throws SyntaxError {
	ValueSource valueSource;

	int ch = sp.peek();
	if (ch>='0' && ch<='9' \|\| ch=='.' \|\| ch=='+' \|\| ch=='-') {
	Number num = sp.getNumber();
	if (num instanceof Long) {
	valueSource = new LongConstValueSource(num.longValue());
	} else if (num instanceof Double) {
	valueSource = new DoubleConstValueSource(num.doubleValue());
	} else {
	// shouldn't happen
	valueSource = new ConstValueSource(num.floatValue());
	}
	} else if (ch == '"' \|\| ch == '\''){
	valueSource = new LiteralValueSource(sp.getQuotedString());
	} else if (ch == '$') {
	sp.pos++;
	String param = sp.getId();
	String val = getParam(param);
	if (val == null) {
	throw new SyntaxError("Missing param " + param + " while parsing function '" + sp.val + "'");
	}

	if ((flags & FLAG_USE_FIELDNAME_SOURCE) != 0 && req.getSchema().getFieldOrNull(val) != null) {
	// Don't try to create a ValueSource for the field, just use a placeholder.
	// this handles the case like x=myfunc($qq)&qq=something
	valueSource = new FieldNameValueSource(val);
	} else {
	QParser subParser = subQuery(val, "func");
	if (subParser instanceof FunctionQParser) {
	((FunctionQParser) subParser).setParseMultipleSources(true);
	}
	Query subQuery = subParser.getQuery();
	if (subQuery == null) {
	valueSource = new ConstValueSource(0.0f);
	} else if (subQuery instanceof FunctionQuery) {
	valueSource = ((FunctionQuery) subQuery).getValueSource();
	} else {
	valueSource = new QueryValueSource(subQuery, 0.0f);
	}
	}

	/***
	// dereference simple argument (i.e., can't currently be a function)
	// In the future we could support full function dereferencing via a stack of ValueSource (or StringParser) objects
	ch = val.length()==0 ? '\0' : val.charAt(0);

	if (ch>='0' && ch<='9' \|\| ch=='.' \|\| ch=='+' \|\| ch=='-') {
	StrParser sp = new StrParser(val);
	Number num = sp.getNumber();
	if (num instanceof Long) {
	valueSource = new LongConstValueSource(num.longValue());
	} else if (num instanceof Double) {
	valueSource = new DoubleConstValueSource(num.doubleValue());
	} else {
	// shouldn't happen
	valueSource = new ConstValueSource(num.floatValue());
	}
	} else if (ch == '"' \|\| ch == '\'') {
	StrParser sp = new StrParser(val);
	val = sp.getQuotedString();
	valueSource = new LiteralValueSource(val);
	} else {
	if (val.length()==0) {
	valueSource = new LiteralValueSource(val);
	} else {
	String id = val;
	SchemaField f = req.getSchema().getField(id);
	valueSource = f.getType().getValueSource(f, this);
	}
	}
	***/

	} else {

	String id = sp.getId();
	if (sp.opt("(")) {
	// a function... look it up.
	ValueSourceParser argParser = req.getCore().getValueSourceParser(id);
	if (argParser==null) {
	throw new SyntaxError("Unknown function " + id + " in FunctionQuery(" + sp + ")");
	}
	valueSource = argParser.parse(this);
	sp.expect(")");
	} else {
	if ("true".equals(id)) {
	valueSource = new BoolConstValueSource(true);
	} else if ("false".equals(id)) {
	valueSource = new BoolConstValueSource(false);
	} else {
	if ((flags & FLAG_USE_FIELDNAME_SOURCE) != 0) {
	// Don't try to create a ValueSource for the field, just use a placeholder.
	valueSource = new FieldNameValueSource(id);
	} else {
	SchemaField f = req.getSchema().getField(id);
	valueSource = f.getType().getValueSource(f, this);
	}
	}
	}

	}

	if ((flags & FLAG_CONSUME_DELIMITER) != 0) {
	consumeArgumentDelimiter();
	}

	return valueSource;
	}

	/** @lucene.experimental */
	public AggValueSource parseAgg(int flags) throws SyntaxError {
	String origId = sp.getId();
	AggValueSource vs = null;
	boolean hasParen;

	if ("agg".equals(origId)) {
	hasParen = sp.opt("(");
	vs = parseAgg(flags \| FLAG_IS_AGG);
	} else {
	// parse as an aggregation...
	String id = origId.startsWith("agg_")? origId: "agg_" + origId;
	hasParen = sp.opt("(");

	ValueSourceParser argParser = req.getCore().getValueSourceParser(id);
	if (argParser == null) {
	argParser = req.getCore().getValueSourceParser(origId);
	if (argParser == null) {
	throw new SyntaxError("Unknown aggregation '" + origId + "' in input (" + sp + ")");
	} else {
	throw new SyntaxError("Expected multi-doc aggregation from '" + origId +
	"' but got per-doc function in input (" + sp + ")");
	}
	}

	ValueSource vv = argParser.parse(this);
	if (!(vv instanceof AggValueSource)) {
	throw new SyntaxError("Expected multi-doc aggregation from '" + origId +
	"' but got (" + vv + ") in (" + sp + ")");
	}
	vs = (AggValueSource) vv;
	}

	if (hasParen) {
	sp.expect(")");
	}

	if ((flags & FLAG_CONSUME_DELIMITER) != 0) {
	consumeArgumentDelimiter();
	}

	return vs;
	}


	/**
	* Consume an argument delimiter (a comma) from the token stream.
	* Only consumes if more arguments should exist (no ending parens or end of string).
	*
	* @return whether a delimiter was consumed
	*/
	protected boolean consumeArgumentDelimiter() throws SyntaxError {
	/* if a list of args is ending, don't expect the comma */
	if (hasMoreArguments()) {
	sp.expect(",");
	return true;
	}

	return false;
	}


	}