Package convex.core.lang

Class AOp<T extends ACell>

java.lang.Object

convex.core.data.AObject

convex.core.data.ACell

convex.core.lang.AOp<T>

Type Parameters:

T - the type of the operation return value

All Implemented Interfaces:

IValidated, IWriteable

Direct Known Subclasses:

AMultiOp, Constant, Def, Lambda, Local, Lookup, Set, Special

public abstract class AOp<T extends ACell>
extends ACell

Abstract base class for CVM operations "...that was the big revelation to me when I was in graduate school—when I finally understood that the half page of code on the bottom of page 13 of the Lisp 1.5 manual was Lisp in itself. These were “Maxwell’s Equations of Software!” This is the whole world of programming in a few lines that I can put my hand over." - Alan Kay

Field Summary

Fields inherited from class convex.core.data.ACell

cachedRef, memorySize

Fields inherited from class convex.core.data.AObject

encoding

Constructor Summary

Constructors

Constructor	Description
AOp()

Method Summary

Modifier and Type	Method	Description
final int	encode(byte[] bs, int pos)	Writes this Cell's encoding to a byte array, including a tag byte which will be written first.
abstract int	encodeRaw(byte[] bs, int pos)	Writes the raw data for this Op to the specified bytebuffer.
boolean	equals(ACell o)	Checks for equality with another Cell.
int	estimatedEncodingSize()	Estimate the encoded data size for this Cell.
abstract Context	execute(Context context)	Executes this op with the given context.
byte	getTag()	Gets the tag byte for this cell.
final AType	getType()	Gets the most specific known runtime Type for this Cell.
boolean	isCanonical()	Returns true if this Cell is in a canonical representation.
final boolean	isCVMValue()	Returns true if this cell is a first class CVM Value allowable in the CVM state Sub-structural cells that are not themselves first class values should return false Records and types that are not permissible on the CVM should return false.
final boolean	isDataValue()	Returns true if this cell instance is a first class value, i.e.
abstract byte	opCode()	Returns the opcode for this op
ACell	toCanonical()	Converts this Cell to a canonical version.
abstract AOp<T>	updateRefs(IRefFunction func)	Updates all Refs in this object using the given function.

Methods inherited from class convex.core.data.ACell

attachMemorySize, attachRef, cachedEncoding, cachedHash, calcMemorySize, createEncoding, createRef, equals, genericEquals, getCanonical, getChildRefs, getEncoding, getEncodingLength, getHash, getMemorySize, getMemorySize, getRef, getRef, getRefCount, hashCode, isEmbedded, toCVMString, toString, validate, validateCell

Methods inherited from class convex.core.data.AObject

attachEncoding, print, print, print

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

AOp

public AOp()

Method Details

execute

public abstract Context execute(Context context)

Executes this op with the given context. Must preserve depth unless an exceptional is returned.

Parameters:

context - Initial Context

Returns:

The updated Context after executing this operation

getType

public final AType getType()

Description copied from class: ACell

Gets the most specific known runtime Type for this Cell.

Overrides:

getType in class ACell

Returns:

The Type of this Call

estimatedEncodingSize

public int estimatedEncodingSize()

Description copied from interface: IWriteable

Estimate the encoded data size for this Cell. Used for quickly sizing buffers. Implementations should try to return a size that is highly likely to contain the entire object when encoded, including the tag byte. Should not traverse soft Refs, i.e. must be usable on arbitrary partial data structures

Returns:

The estimated size for the binary representation of this object.

isCanonical

public boolean isCanonical()

Description copied from class: ACell

Returns true if this Cell is in a canonical representation. Non-canonical objects may be used on a temporary internal basis, they should be converted to canonical representations for general purpose use.

Specified by:

isCanonical in class ACell

Returns:

true if the object is in canonical format, false otherwise

toCanonical

public ACell toCanonical()

Description copied from class: ACell

Converts this Cell to a canonical version. Must return this Cell if already canonical, may be O(n) in size of value otherwise. Callers should usually use getCanonical(), which caches canonical instances once created

Specified by:

toCanonical in class ACell

Returns:

Canonical version of Cell

isCVMValue

public final boolean isCVMValue()

Description copied from class: ACell

Returns true if this cell is a first class CVM Value allowable in the CVM state Sub-structural cells that are not themselves first class values should return false Records and types that are not permissible on the CVM should return false. Pretty much everything else should return true. Note: CVM values might not be in a canonical format, e.g. temporary data structures

Specified by:

isCVMValue in class ACell

Returns:

true if the object is a CVM Value, false otherwise

isDataValue

public final boolean isDataValue()

Description copied from class: ACell

Returns true if this cell instance is a first class value, i.e. not a component of a larger data structure Sub-structural cells that are not themselves first class values should return false Everything else should return true.

Specified by:

isDataValue in class ACell

Returns:

true if the object is a Value, false otherwise

opCode

public abstract byte opCode()

Returns the opcode for this op

Returns:

Opcode as a byte

encode

public final int encode(byte[] bs,
 int pos)

Description copied from class: ACell

Writes this Cell's encoding to a byte array, including a tag byte which will be written first. Cell must be canonical, or else an error may occur.

Specified by:

encode in interface IWriteable

Specified by:

encode in class ACell

Parameters:

bs - A byte array to which to write the encoding

pos - The offset into the byte array

Returns:

New position after writing

encodeRaw

public abstract int encodeRaw(byte[] bs,
 int pos)

Writes the raw data for this Op to the specified bytebuffer. Assumes Op tag and opcode already written.

Specified by:

encodeRaw in class ACell

Parameters:

bs - Byte array to write to

pos - Position to write in byte array

Returns:

The updated position

updateRefs

public abstract AOp<T> updateRefs(IRefFunction func)

Description copied from class: ACell

Updates all Refs in this object using the given function. The function *must not* change the hash value of Refs, in order to ensure structural integrity of modified data structures. The implementation *should* re-attach any original encoding in order to prevent re-encoding or surplus hashing This is a building block for a very sneaky trick that enables use to do a lot of efficient operations on large trees of smart references. Must return the same object if no Refs are altered.

Overrides:

updateRefs in class ACell

Parameters:

func - Ref update function

Returns:

Cell with updated Refs

getTag

public byte getTag()

Description copied from class: ACell

Gets the tag byte for this cell. The tag byte is always equal to the first byte of the Cell's canonical Encoding, and is sufficient to distinguish how to read the rest of the encoding.

Specified by:

getTag in class ACell

Returns:

Tag byte for this Cell

equals

public boolean equals(ACell o)

Description copied from class: ACell

Checks for equality with another Cell. In general, Cells are considered equal if they have the same canonical representation, i.e. an identical encoding with the same hash value. Subclasses SHOULD override this if they have a more efficient equals implementation. MUST NOT require reads from Store.

Specified by:

equals in class ACell

Parameters:

o - Cell to compare with. May be null.

Returns:

True if this cell is equal to the other object