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Created Mar 7, 2011

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<amac> (doc gen-class)
<sexpbot> ⟹ "Macro ([& options]); When compiling, generates compiled
bytecode for a class with the given package-qualified :name (which, as
all names in these parameters, can be a string or symbol), and writes
the .class file to the *compile-path* directory. When not compiling,
does nothing. The gen-class construct contains no implementation, as
the implementation will be dynamically sought by the generated class
in functions in an implementing Clojure namespace. Given a generated
class org.mydomain.MyClass with a method named mymethod, gen-class
will generate an implementation that looks for a function named by
(str prefix mymethod) (default prefix: \"-\") in a Clojure namespace
specified by :impl-ns (defaults to the current namespace). All
inherited methods, generated methods, and init and main functions (see
:methods, :init, and :main below) will be found similarly prefixed. By
default, the static initializer for the generated class will attempt
to load the Clojure support code for the class as a resource from the
classpath, e.g. in the example case, ``org/mydomain/MyClass__init.class``.
This behavior can be controlled by :load-impl-ns Note that methods
with a maximum of 18 parameters are supported. In all subsequent
sections taking types, the primitive types can be referred to by their
Java names (int, float etc), and classes in the java.lang package can
be used without a package qualifier. All other classes must be fully
qualified. Options should be a set of key/value pairs, all except for
:name are optional: :name aname The package-qualified name of the
class to be generated :extends aclass Specifies the superclass, the
non-private methods of which will be overridden by the class. If not
provided, defaults to Object. :implements [interface ...] One or more
interfaces, the methods of which will be implemented by the class.
:init name If supplied, names a function that will be called with the
arguments to the constructor. Must return [ [superclass-constructor-args]
state] If not supplied, the constructor args are passed directly to
the superclass constructor and the state will be nil :constructors
{[param-types] [super-param-types], ...} By default, constructors are
created for the generated class which match the signature(s) of the
constructors for the superclass. This parameter may be used to
explicitly specify constructors, each entry providing a mapping from a
constructor signature to a superclass constructor signature. When you
supply this, you must supply an :init specifier. :post-init name If
supplied, names a function that will be called with the object as the
first argument, followed by the arguments to the constructor. It will
be called every time an object of this class is created, immediately
after all the inherited constructors have completed. It's return value
is ignored. :methods [ [name [param-types] return-type], ...] The
generated class automatically defines all of the non-private methods
of its superclasses/interfaces. This parameter can be used to specify
the signatures of additional methods of the generated class. Static
methods can be specified with ^{:static true} in the signature's
metadata. Do not repeat superclass/interface signatures here. :main
boolean If supplied and true, a static public main function will be
generated. It will pass each string of the String[] argument as a
separate argument to a function called (str prefix main). :factory
name If supplied, a (set of) public static factory function(s) will be
created with the given name, and the same signature(s) as the
constructor(s). :state name If supplied, a public final instance field
with the given name will be created. You must supply an :init function
in order to provide a value for the state. Note that, though final,
the state can be a ref or agent, supporting the creation of Java
objects with transactional or asynchronous mutation semantics.
:exposes {protected-field-name {:get name :set name}, ...} Since the
implementations of the methods of the generated class occur in Clojure
functions, they have no access to the inherited protected fields of
the superclass. This parameter can be used to generate public
getter/setter methods exposing the protected field(s) for use in the
implementation. :exposes-methods {super-method-name exposed-name, ...}
It is sometimes necessary to call the superclass' implementation of an
overridden method. Those methods may be exposed and referred in the
new method implementation by a local name. :prefix string Default:
\"-\" Methods called e.g. Foo will be looked up in vars called
prefixFoo in the implementing ns. :impl-ns name Default: the name of
the current ns. Implementations of methods will be looked up in this
namespace. :load-impl-ns boolean Default: true. Causes the static
initializer for the generated class to reference the load code for the
implementing namespace. Should be true when implementing-ns is the
default, false if you intend to load the code via some other
method."
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