frege.runtime

Class Runtime

java.lang.Object

frege.runtime.Runtime

public class Runtime
extends java.lang.Object

Miscellaneous functions and methods needed in frege.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	emptyString The empty polymorphic value of type StringJ a
private static int	exitCode set this if you need a different exit code
static java.lang.ThreadLocal<java.io.PrintWriter>	stderr Provide UTF-8 encoded standard printer for stderr with autoflush
static java.lang.ThreadLocal<java.io.BufferedReader>	stdin Provide UTF-8 decoded standard input Reader
static java.lang.ThreadLocal<java.io.PrintWriter>	stdout Provide UTF-8 encoded standard printer for stdout with automatic line flushing
static java.util.Random	stdRandom GLobal Random generator

Constructor Summary

Constructors

Constructor and Description
Runtime()

Method Summary

Methods

Modifier and Type	Method and Description
static <T> T[]	arrayThaw(T[] a) Thaw a readonly array by cloning it
static <A> java.lang.Class<A>	classForName(java.lang.String x) Implementation for frege.prelude.PreludeBase.Class.forName
static int	constructor(java.lang.Object v)
static int	constructor(Value v) Implementation for pure native constructor frege.runtime.Runtime.constructor :: a -> Int
static <T extends java.io.Serializable> T	copySerializable(T o) This is used to copy a mutable value.
static void	exit()
static <A> java.lang.Class<A>	getClass(A o) Implementation for frege.prelude.PreludeBase.getClass
static <T> T	identity(T x) Identity function for reference types (Can be used to pseudo thaw/freeze a value)
static java.lang.Object	itemAt(java.lang.String value, int offset) Cheat with phantom types.
static java.lang.String	quoteChr(char c) Utility method used by Char.show to quote a character.
static java.lang.String	quoteStr(java.lang.String a) Utility method used by String.show to quote a string.
static java.lang.Integer	runMain(java.lang.Object arg) Run a IO action as main program.
static void	setExitCode(int a)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

stdRandom

public static final java.util.Random stdRandom

GLobal Random generator

stdout

public static java.lang.ThreadLocal<java.io.PrintWriter> stdout

Provide UTF-8 encoded standard printer for stdout with automatic line flushing

Must be thread local so that it works in the online REPL, for instance.

stderr

public static java.lang.ThreadLocal<java.io.PrintWriter> stderr

Provide UTF-8 encoded standard printer for stderr with autoflush

Must be thread local so that it works in the online REPL, for instance.

stdin

public static java.lang.ThreadLocal<java.io.BufferedReader> stdin

Provide UTF-8 decoded standard input Reader

emptyString

public static final java.lang.String emptyString

The empty polymorphic value of type StringJ a

Referenced in frege.prelude.List.ListLike_StringJ

See Also:

Constant Field Values

exitCode

private static volatile int exitCode

set this if you need a different exit code

Constructor Detail

Runtime

public Runtime()

Method Detail

constructor

public static final int constructor(Value v)

Implementation for pure native constructor frege.runtime.Runtime.constructor :: a -> Int

constructor

public static final int constructor(java.lang.Object v)

getClass

public static final <A> java.lang.Class<A> getClass(A o)

Implementation for frege.prelude.PreludeBase.getClass

classForName

public static final <A> java.lang.Class<A> classForName(java.lang.String x)
                                             throws java.lang.ClassNotFoundException

Implementation for frege.prelude.PreludeBase.Class.forName

Throws:

java.lang.ClassNotFoundException

quoteStr

public static final java.lang.String quoteStr(java.lang.String a)

Utility method used by String.show to quote a string.

quoteChr

public static final java.lang.String quoteChr(char c)

Utility method used by Char.show to quote a character.

copySerializable

public static final <T extends java.io.Serializable> T copySerializable(T o)

This is used to copy a mutable value.

The returned value is of same type, but is considered immutable. Suitable for instances of classes that do not implement Cloneable, but do implement Serializable.

Parameters:

o - the value to copy

Returns:

a copy obtained by serialization of the argument value, followed by deserialization

identity

public static final <T> T identity(T x)

Identity function for reference types (Can be used to pseudo thaw/freeze a value)

arrayThaw

public static final <T> T[] arrayThaw(T[] a)

Thaw a readonly array by cloning it

itemAt

public static final java.lang.Object itemAt(java.lang.String value,
                      int offset)

Cheat with phantom types.

This method is announced with type String a -> Int -> a but it always returns a char.

This is fine as long as nobody is able to actually create a value with type, say String Int.
This could be done only with another malicious native function, though.

runMain

public static java.lang.Integer runMain(java.lang.Object arg)

Run a IO action as main program.

*

Called from the java main method of a frege program. This converts the argument String array to a list and passes this to the compiled frege main function, if it is a function. The result is an IO action of type IO a to which then IO.performUnsafe is applied. The resulting Lambda then actually executes the frege code when evaluated.

exit

public static final void exit()

setExitCode

public static final void setExitCode(int a)