## net.sf.saxon.functions
Class StandardFunction

    java.lang.Object
      net.sf.saxon.functions.StandardFunction

    public abstract class StandardFunction

extends Object

This class contains static data tables defining the properties of standard functions. "Standard functions" here means the XPath 2.0 functions, the XSLT 2.0 functions, and a few selected extension functions which need special recognition.

Nested Class Summary
`static class` `StandardFunction.Entry` An entry in the table describing the properties of a function

Method Summary
`static void` `arg(StandardFunction.Entry e, int a, ItemType type, int cardinality, Value resultIfEmpty)` Add information to a function entry about the argument types of the function
`static StandardFunction.Entry` `getFunction(String name, int arity)` Get the table entry for the function with a given name
`static StandardFunction.Entry` `makeEntry(String name, Class implementationClass, int opcode, int minArguments, int maxArguments, ItemType itemType, int cardinality)` Make a table entry describing the signature of a function, with a reference to the implementation class.

Methods inherited from class java.lang.Object
`equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Method Detail

### makeEntry

    public static StandardFunction.Entry makeEntry(String name,
                                                   Class implementationClass,
                                                   int opcode,
                                                   int minArguments,
                                                   int maxArguments,
                                                   ItemType itemType,
                                                   int cardinality)

  Make a table entry describing the signature of a function, with a reference to the implementation class.

  Parameters:
    `name` - the function name
    `implementationClass` - the class used to implement the function
    `opcode` - identifies the function when a single class implements several functions
    `minArguments` - the minimum number of arguments required
    `maxArguments` - the maximum number of arguments allowed
    `itemType` - the item type of the result of the function
    `cardinality` - the cardinality of the result of the function
  Returns:
    the entry describing the function. The entry is incomplete, it does not yet contain information about the function arguments.

### arg

    public static void arg(StandardFunction.Entry e,
                           int a,
                           ItemType type,
                           int cardinality,
                           Value resultIfEmpty)

  Add information to a function entry about the argument types of the function

  Parameters:
    `e` - the entry for the function
    `a` - the position of the argument, counting from zero
    `type` - the item type of the argument
    `cardinality` - the cardinality of the argument
    `resultIfEmpty` - the value returned by the function if an empty sequence appears as the value, when this result is unaffected by any other arguments

### getFunction

    public static StandardFunction.Entry getFunction(String name,
                                                     int arity)

  Get the table entry for the function with a given name

  Parameters:
    `name` - the name of the function. This may be an unprefixed local-name for functions in the system namespace, or may use the conventional prefix "saxon:" in the case of Saxon extension functions that are specially recognized
  Returns:
    if the function name is known, an Entry containing information about the function. Otherwise, null

Copyright (C) Michael H. Kay. All rights reserved.