org.erights.e.elang.smallcaps
Class SmallcapsActivation

java.lang.Object
  |
  +--org.erights.e.elang.smallcaps.SmallcapsActivation

All Implemented Interfaces:

SmallcapsOps

public class SmallcapsActivation

extends Object

implements SmallcapsOps

Untamed: The state of one activation frame in a Smallcaps call stack.

XXX This is an incomplete, broken reference implementation -- fix me!

Author:

Mark S. Miller, Darius Bacon

Field Summary

private static ClassDesc	BooleanGuard Needed from branching
private static ClassDesc	EListGuard Needed for list-pattern matching.
private byte[]	myCode
private EvalContext	myCtx
private SmallcapsHandler[]	myHandlerStack
private int	myHandlerTOS
private Object[]	myOperandStack
private int	myPC
private int	myTOS The top of the operand stack.

Fields inherited from interface org.erights.e.elang.smallcaps.SmallcapsOps

ADDR_FRAME, ADDR_FRAME_SLOT, ADDR_LITERAL, ADDR_LOCAL, ADDR_LOCAL_SLOT, ADDR_OUTER_SLOT, OP_ASSIGN, OP_BIND, OP_BIND_SLOT, OP_BRANCH, OP_CALL, OP_CALL_ONLY, OP_CDR_PATT, OP_CHAR, OP_DUP, OP_EJECTOR, OP_EJECTOR_ONLY, OP_END_HANDLER, OP_FALSE, OP_FLOAT64, OP_JUMP, OP_LIST_PATT, OP_NEG_INT, OP_NOUN, OP_NULL, OP_OBJECT, OP_POP, OP_RETURN, OP_ROT, OP_SCOPE, OP_SEND, OP_SEND_ONLY, OP_SLOT, OP_STRING, OP_SWAP, OP_TRUE, OP_TRY, OP_TWINE, OP_UNWIND, OP_WHOLE_NUM

Constructor Summary

SmallcapsActivation(byte[] code, int pc, EvalContext ctx)
Enabled:

Method Summary

Object	eval() Enabled:
private void	handle(Object problem) Handle the problem using the top handler on the handler stack.
private void	handle(OneArgFunc optEjector, Object problem) Handle the problem using optEjector, if it's not null, or the top handler on the handler stack if optEjector is null.
private OneArgFunc	makeEjector(int label)
private OneArgFunc	makeEjectorOnly(int label)
private Object	pop()
private void	popHandler()
private Object[]	popN(int n)
private void	push(Object operand)
private void	pushHandler()
private void	pushHandler(OneArgFunc ejector)
private void	pushTryHandler(int label)
private char	readChar()
private double	readFloat64()
private int	readLabel()
private String	readUTF()
private int	readWholeInt()
private BigInteger	readWholeNum()

Methods inherited from class java.lang.Object

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

Field Detail

EListGuard

private static final ClassDesc EListGuard

Needed for list-pattern matching.

BooleanGuard

private static final ClassDesc BooleanGuard

Needed from branching

myCode

private final byte[] myCode

myPC

private int myPC

myOperandStack

private final Object[] myOperandStack

myTOS

private int myTOS

The top of the operand stack.

myHandlerStack

private final SmallcapsHandler[] myHandlerStack

myHandlerTOS

private int myHandlerTOS

myCtx

private final EvalContext myCtx

Constructor Detail

SmallcapsActivation

public SmallcapsActivation(byte[] code,
                           int pc,
                           EvalContext ctx)

Enabled:

Method Detail

push

private void push(Object operand)

pop

private Object pop()

popN

private Object[] popN(int n)

Parameters:

n - How many to pop

Returns:

An n-element array of the popped elements, from bottom-most to top-most.

handle

private void handle(Object problem)

Handle the problem using the top handler on the handler stack.

Parameters:

problem -

handle

private void handle(OneArgFunc optEjector,
                    Object problem)

Handle the problem using optEjector, if it's not null, or the top handler on the handler stack if optEjector is null.

optEjector may include user-defined behavior. If optEjector returns normally, then invoke the top handler on the handler stack to handle this inappropriate return.

Parameters:

optEjector -

problem -

popHandler

private void popHandler()

pushHandler

private void pushHandler()

pushHandler

private void pushHandler(OneArgFunc ejector)

Parameters:

ejector -

pushTryHandler

private void pushTryHandler(int label)

Parameters:

label -

makeEjectorOnly

private OneArgFunc makeEjectorOnly(int label)

Returns:

makeEjector

private OneArgFunc makeEjector(int label)

Returns:

readWholeNum

private BigInteger readWholeNum()

See Also:

SmallcapsEncoderVisitor#writeWholeNum(BigInteger)

readWholeInt

private int readWholeInt()

See Also:

SmallcapsEncoderVisitor#writeWholeNum(int)

readLabel

private int readLabel()

Returns:

readUTF

private String readUTF()

Returns:

readChar

private char readChar()

Returns:

readFloat64

private double readFloat64()

Returns:

eval

public Object eval()

Enabled: