Module Simula

Package simula.runtime

Class RTS_Head

java.lang.Object

simula.runtime.RTS_RTObject

simula.runtime.RTS_ENVIRONMENT

simula.runtime.RTS_BASICIO

simula.runtime.RTS_CLASS

simula.runtime.RTS_Linkage

simula.runtime.RTS_Head

All Implemented Interfaces:

Runnable

public class RTS_Head
extends RTS_Linkage

System class Head.

  linkage class head;
          begin
             ref (link) procedure first; first :- suc;
             ref (link) procedure last;   last :- pred;
             Boolean procedure empty;    empty := SUC == this linkage;
 
             integer procedure cardinal;
             begin integer i;
                ref (link) ptr;
                ptr :- first;
                while ptr =/= none do begin
                   i   := i+1;
                   ptr :- ptr.suc
                end while;
                cardinal := i
             end cardinal;
 
             procedure clear;  while first =/= none do first.out;
 
             SUC :- PRED :- this linkage
          end head;
 

An object of the class "head", or a subclass of "head" is used to represent a set. "head" objects may not acquire set membership. Thus, a unique "head" is defined for each set.

Link to GitHub: Source File.

Author:

SIMULA Standards Group, Øystein Myhre Andersen

Nested Class Summary

Nested classes/interfaces inherited from class simula.runtime.RTS_RTObject

RTS_RTObject.ForElt, RTS_RTObject.ForList, RTS_RTObject.ForListIterator, RTS_RTObject.OperationalState, RTS_RTObject.RTS_BOOLEAN_ARRAY, RTS_RTObject.RTS_BOUNDS, RTS_RTObject.RTS_CHARACTER_ARRAY, RTS_RTObject.RTS_INTEGER_ARRAY, RTS_RTObject.RTS_LABEL, RTS_RTObject.RTS_LONG_REAL_ARRAY, RTS_RTObject.RTS_NAME<T>, RTS_RTObject.RTS_REAL_ARRAY, RTS_RTObject.RTS_REALTYPE_ARRAY, RTS_RTObject.RTS_REF_ARRAY<T>, RTS_RTObject.RTS_TEXT_ARRAY, RTS_RTObject.SingleElt<T>, RTS_RTObject.SingleTValElt, RTS_RTObject.StepUntil, RTS_RTObject.UncaughtExceptionHandler, RTS_RTObject.WhileElt<T>, RTS_RTObject.WhileTValElt

Field Summary

Fields inherited from class simula.runtime.RTS_Linkage

PRED, SUC

Fields inherited from class simula.runtime.RTS_ENVIRONMENT

_STARTTIME, CURRENTDECIMALMARK, CURRENTLOWTEN, EXCEPTION_HANDLER, maxint, maxlongreal, maxreal, minint, minlongreal, minreal, simulaReleaseID

Fields inherited from class simula.runtime.RTS_RTObject

_CORUT, _CTX, _CUR, _DL, _INPUT_LINELENGTH, _JTX, _OUTPUT_LINELENGTH, _SL, _STATE, _SYSIN, _SYSOUT, NOTEXT

Constructor Summary

Constructors

Constructor	Description
RTS_Head(RTS_RTObject SL)	Construct a new set(Head) with no members.

Method Summary

Modifier and Type	Method	Description
RTS_Head	_STM()	Method representing the Statements in this Block This method is virtual and must be redefined in blocks.
int	cardinal()	The integer procedure "cardinal" counts the number of members in a set.
void	clear()	The procedure "clear" removes all members from the set.
boolean	empty()	The Boolean procedure "empty" gives the value true only if the set has no members.
RTS_Link	first()	The procedure "first" may be used to obtain a reference to the first member of the set.
RTS_Link	last()	The procedure "last" may be used to obtain a reference to the last member of the set.

Methods inherited from class simula.runtime.RTS_Linkage

pred, prev, suc

Methods inherited from class simula.runtime.RTS_CLASS

_START, run

Methods inherited from class simula.runtime.RTS_BASICIO

toString

Methods inherited from class simula.runtime.RTS_ENVIRONMENT

_char, _IPOW, _IS, abs, abs, abs, addepsilon, addepsilon, arccos, arcsin, arctan, arctan2, Char, clocktime, cos, cosh, cotan, cputime, datetime, decimalmark, DEFEXCEPTION, digit, discrete, draw, edfix, edit, edit, edit, edit, edit, edtime, entier, Erlang, error, exp, getIntInfo, getTextInfo, giveIntInfo, giveTextInfo, hash, histd, histo, isochar, isorank, letter, linear, ln, loadChar, log10, lowcase, lowerbound, lowten, max, max, max, max, max, min, min, min, min, min, mod, negexp, normal, Poisson, printStaticChain, printThreadList, randint, rank, rem, rts_utility, sign, simulaid, sin, sinh, sqrt, storeChar, subepsilon, subepsilon, tan, tanh, uniform, upcase, upperbound, waitSomeTime

Methods inherited from class simula.runtime.RTS_RTObject

_ASGSTR, _ASGTXT, _GOTO, _JUMPTABLE, _JUMPTABLE, _LABEL, _PRE_LABEL, _PRE_TABLE, _SIM_LABEL, _TXTREL_EQ, _TXTREL_GE, _TXTREL_GT, _TXTREL_LE, _TXTREL_LT, _TXTREL_NE, _VALUE, arrayValue, BBLK, blanks, BPRG, call, call, CONC, copy, detach, detach, detach, doubleValue, EBLK, edObjectAttributes, edObjectIdent, floatValue, getErrorMessage, intValue, isDetachUsed, isQPSystemBlock, objectTraceIdentifier, objectTraceIdentifier, objectValue, procValue, resume, resume, resume, swapCoroutines, sysin, sysout, terminate_program, TRACE_GOTO, TRF_EQ, TRF_NE

Methods inherited from class java.lang.Object

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

Constructor Details

RTS_Head

public RTS_Head(RTS_RTObject SL)

Construct a new set(Head) with no members.

The references SUC and PRED initially point to the "head" itself, which thereby represents an empty set.

Parameters:

SL - staticLink

Method Details

_STM

public RTS_Head _STM()

Description copied from class: RTS_RTObject

Method representing the Statements in this Block
This method is virtual and must be redefined in blocks.

Overrides:

_STM in class RTS_Linkage

Returns:

a pointer to this _RTObject

first

public RTS_Link first()

The procedure "first" may be used to obtain a reference to the first member of the set.

Returns:

The first member of the set(Head)

last

public RTS_Link last()

The procedure "last" may be used to obtain a reference to the last member of the set.

Returns:

The last member of the set(Head)

empty

public boolean empty()

The Boolean procedure "empty" gives the value true only if the set has no members.

Returns:

true iff no members.

cardinal

public int cardinal()

The integer procedure "cardinal" counts the number of members in a set.

Returns:

the number of members in this set

clear

public void clear()

The procedure "clear" removes all members from the set.