sisc.exprs
Class IfEval

java.lang.Object
  sisc.util.Util
      sisc.data.Expression
          sisc.exprs.IfEval

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, OptimisticHost, ExpressionVisitee, Version

public class IfEval
extends Expression
implements OptimisticHost

See Also:

Serialized Form

Field Summary

Expression	altern
Expression	conseq

Fields inherited from class sisc.data.Expression

annotations, EMPTYSET

Fields inherited from class sisc.util.Util

BACKQUOTE, BEGIN, bundles, caseSensitive, EMPTYLIST, EMPTYVEC, EOF, ERRORK, EVAL, EXPSC, EXPTOP, FALSE, FCONT, FIVE, JEXCEPTION, LAMBDA, LOCATION, maxFloatPrecision, MESSAGE, minFloatPrecision, NAME, OTHER, PARENT, permitInterrupts, QUOTE, QUOTESYM, REPORT, SETBANG, SISC, SISC_SPECIFIC, SISCB, SOURCE_COLUMN, SOURCE_FILE, SOURCE_LINE, SYMENV, THIS, TOPLEVEL, TRUE, UNQUOTE, UNQUOTE_SPLICING, VOID, ZV

Fields inherited from interface sisc.util.Version

VERSION

Constructor Summary

IfEval()

IfEval(Expression conseq, Expression altern)

Method Summary

void	alter(Interpreter r, int uexpPosition, Expression replaceWith) Instructs the host to replace the uExp referenced at the given (Expression dependent) position, with the given Expression.
void	deserialize(Deserializer s) All Expressions must implement a default (no-argument) constructor.
void	eval(Interpreter r) All expressions can be evaluated to some Scheme value.
Value	express() A debugging function, express returns a Scheme value that describes this expression.
void	serialize(Serializer s) All Expressions must implement a default (no-argument) constructor.
void	setHosts()
boolean	visit(ExpressionVisitor v)

Methods inherited from class sisc.data.Expression

deserializeAnnotations, getAnnotation, getAnnotation, getAnnotationKeys, getAnnotations, getName, getValue, readExternal, readResolve, serializeAnnotations, setAnnotation, setAnnotation, setName, visitAnnotations, writeExternal

Methods inherited from class sisc.util.Util

annotated, annotatedAppEval, append, argCheck, argsToSymbols, assq, bininport, bininstream, binoutport, binoutstream, box, character, charinport, charinreader, charoutport, charoutwriter, charsetFromString, chr, cont, currentClassLoader, env, error, error, error, error, error, error, error, expr, getDefaultCharacterSet, immutablePair, immutableVector, inport, javaExceptionToString, javaWrap, justify, length, liMessage, liMessage, liMessage, liMessage, liMessage, liMessage, liMessage, list, list, list, list, list, makeURL, mapcar, memq, nlib, num, outport, pair, pairToExpressions, pairToExpVect, pairToValues, proc, read, registerBundle, reverse, reverseInPlace, simpleErrorToString, sourceAnnotations, str, string, sym, symbol, symval, truePair, truth, truth, typeError, typeError, updateName, url, url, url, valArrayToList, valArrayToList, valArrayToVec, vec, warn, warn, warn

Methods inherited from class java.lang.Object

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

Field Detail

conseq

public Expression conseq

altern

public Expression altern

Constructor Detail

IfEval

public IfEval(Expression conseq,
              Expression altern)

IfEval

public IfEval()

Method Detail

setHosts

public void setHosts()

Specified by:

setHosts in interface OptimisticHost

eval

public void eval(Interpreter r)
          throws ContinuationException

Description copied from class: Expression

All expressions can be evaluated to some Scheme value. This function implements the exact manner in which an expression is evaluated. An expression, when evaluated, performs some action that results in its value being placed in the acc register of the given Interpreter. An expression that immediately evaluates to a value (i.e. does not require that an additional expression be evaluated to obtain its value) must clear the nxp register by setting it to null. Otherwise, nxp should be set to the expression that is to be evaluated next before this method returns.

Specified by:

eval in class Expression

Parameters:

r - the Interpreter

Throws:

ContinuationException

express

public Value express()

Description copied from class: Expression

A debugging function, express returns a Scheme value that describes this expression. See examples in sisc.exprs.*

Specified by:

express in class Expression

serialize

public void serialize(Serializer s)
               throws java.io.IOException

Description copied from class: Expression

All Expressions must implement a default (no-argument) constructor. Those that wish to be serialized to a heap must implement both this and the deserialize method. The Expression may use any method of the Serializer, which implements java.io.DataOutput to write its state.

Overrides:

serialize in class Expression

Parameters:

s - the Serializer

Throws:

java.io.IOException

deserialize

public void deserialize(Deserializer s)
                 throws java.io.IOException

Description copied from class: Expression

All Expressions must implement a default (no-argument) constructor. Those that wish to b serialized to a heap must implement both this and the serialize method. The Expression may use any method of the DataInput stream and the Deserializer serialization context to read its state.

Overrides:

deserialize in class Expression

Parameters:

s - the Deserializer

Throws:

java.io.IOException

visit

public boolean visit(ExpressionVisitor v)

Specified by:

visit in interface ExpressionVisitee

Overrides:

visit in class Expression

alter

public void alter(Interpreter r,
                  int uexpPosition,
                  Expression replaceWith)

Description copied from interface: OptimisticHost

Instructs the host to replace the uExp referenced at the given (Expression dependent) position, with the given Expression.

Specified by:

alter in interface OptimisticHost

uexpPosition - Expression dependent uExp index

replaceWith - Expression to revert to