Example types and object implementations.. NEL, Intropar

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1 Example types and object implementations. NEL, Intropar

2 Objektmodel Et Emerald objekt består af: et navn, der identificerer objektet en repræsentation nogle operationer (funktioner) måske en process. NEL, Intropar

3 Indkapsling const theaccount object bankaccount var deposits : integer 0 var withdrawals : integer 0 export operation deposit[amount : integer ] deposits deposits + amount end deposit export operation withdraw [amount : integer ] withdrawals withdrawals + amount end deposit export function fetchbalance[] [result : integer ] result deposits - withdrawals end fetchbalance end bankaccount. NEL, Intropar

4 At lave mange objekter loop object bankaccount var balance : Integer export operation deposit[amount : Integer ]... export operation withdraw [amount : Integer ]... export operation fetchbalance... end bankaccount exit when <enough accounts> end loop. NEL, Intropar

5 Operatorer Prec Operator Operation Level 1 view-as Widen view of object s operations restrict-to Restrict view of object s operations 2 Logical or or Logical conditional (short-circuit) or 3 & Logical and and Logical conditional (short-circuit) and 4! Logical negation 5 ==,!== Object identity and distinction > Type conformity =,! =, <, <=, >=, > Relational operators 6 +, Additive operators 7 *, / Multiplicative operators # Modulus User-defined 8, Arithmetic negation isfixed Checks if object is fixed at node locate Finds a possible location of the operand awaiting Processes waiting on condition nameof Name of an object typeof Type of an object. NEL, Intropar

6 Tildeling lb, rb oparent.brothers[self ] foo nil x,y y,x x,y,z 3, foo.f. NEL, Intropar

7 Betinget udførelse ifstm ::= if expression then declarationsandstatements { elseif expression then declarationsandstatements } [ else declarationsandstatements ] end if. NEL, Intropar

8 Løkker for ( initial : condition : step ) % declarationsandstatements end for Er det samme som: begin initial loop exit when!condition begin % declarationsandstatements end step end loop end. NEL, Intropar

9 Mere syntaktisk sukker sukker ob$foo ob$foo bar vec[foo] vec[foo] bar er det samme som ob.getfoo ob.setfoo[bar] vec.getelement[foo] vec.setelement[foo,bar] Også Class, Field. NEL, Intropar

10 Invokering procedureinv ::= expression. operationnavn[ arglist ] operationnm ::= identifier operator argumentlist ::= [ argument {, argument } ] argument ::= [ move ] [ visit ] expression foo.bar [a1, a2].bar1[foo1.bar2[42]] 42.+[27] NEL, Intropar

11 Flytning movestatement ::= move exp 1 to exp 2 const knude == object knudetest process %... etobjekt.foo[move etandetobjekt] etobjekt.foo[visit etandetobjekt] end process end knudetest move detteobjekt to mig attached var x anobject. NEL, Intropar

12 Fiksering fixstatement ::= fix exp 1 at exp 2 unfixstatement ::= unfix expression refixstatement ::= refix exp 1 at exp 2 fix object at (locate self ) refix (locate self ) at (locate nabo). NEL, Intropar

13 Compound statement compoundstm ::= begin blockbody end blockbody ::= declarationsandstatements [ unavailablehandler ] [ failurehandler ] unavailhandler ::= when identifier [: typedenotation] unavailable declarationsandstatements end unavailable failurehandler ::= failure declarationsandstatements end failure. NEL, Intropar

14 Handlers begin foo.f [p] when foo unavailable foo = foogen.create foo.f [p] end unavailable end. NEL, Intropar

15 Synkronisering const ColaMonitor == object cm const colapris == 10 monitor var ColaKredit var ColaForbrug operation drik ColaKredit ColaKredit - colapris ColaForbrug ColaForbrug + 1 end drik operation betal[beløb] ColaKredit ColaKredit + beløb end betal end monitor operation betalhund betal[100] end betalhund end cm. NEL, Intropar

16 Readers and Writers object crres monitor const index set.of [elementtype].create var readers : integer 0 var writing : boolean false const OKtoWrite condition.create const OKtoRead condition.create operation startread if writing or awaiting OKtoWrite then wait OKtoRead end if readers readers+1 signal OKtoRead end StartRead operation endread if readers < 1 then return end if readers readers-1 if readers = 0 then signal OKtoWrite end if end endread. NEL, Intropar

17 operation startwrite if readers>0 or writing then wait OKtoWrite writing true end if end startwrite operation endwrite writing false if awaiting OKtoRead then signal OKtoRead else signal OKtoWrite end if end endwrite end monitor end crres

18 Typer Organismer Dyr Planter Pattedyr Øgler Rovdyr Drøvtyggere. NEL, Intropar

19 Resultater er gode const organismetype == type org function getname [string] end org const pattetype == type pattedyr function getname [string] operation producerer [gødning] end pattedyr const drøvtype == type drøv function getname [string] operation producerer [drøvtyggergødning] end drøv var g : gødning var p : pattedyr var endrøvtygger : drøvtype... var etpattedyr : PatteType... if x>0 then p etpattedyr else p endrøvtygger end if g p.producerer g.spred. NEL, Intropar

20 Parametre er lumske const organismetype == type org function getname [string] end org const pattetype == type pattedyr function getname [string] operation spis[organismetype] end pattedyr const drøvtype == type drøv function getname [string] operation spis[plantetype] end drøv const rovtype == type rov function getname [string] operation spis[dyrtype] end rov var mad : organismetype enko var p : pattedyr var endrøvtygger : drøvtype var etpattedyr : PatteType if x>0 then p etrovdyr else p endrøvtygger end if p.spis[mad]. NEL, Intropar

21 Hvad er forholdet? const pattetype == type pattedyr function getname [string] operation omsætter [organismetype] [gødning] end pattedyr const drøvtype == type drøv function getname [string] operation omsætter [plantetype] [drøvtyggergødning] end drøv. NEL, Intropar

22 Typisk indsætning og udtagning. NEL, Intropar

23 const holderclass == object holderc export function of [ElementType : AbstractType] [vresult : ht ] where ht == immutable type aht operation create[integer ] [holdert ] function getsignature [Signature] end aht holdert == type hold operation indsæt[elementtype] function udtag [elementtype] end hold end where vresult immutable object HolderGenerator export operation create [nyholder : ht ] nyholder object dennyeholder var elem : elementtype export operation indsæt[e : elementtype] elem e end inds export function udtag [e : elementtype] e elem end udtag end dennyeholder end create export function getsignature [sresult : Signature] sresult ht end getsignature end HolderGenerator end of end holderc

24 Brug const person == type pt function getname [string] end pt const teacher == type tt function getname [string] operation udbetalløn end udbetall const student == type st function getname [string] operation opkrævkopiafgift end st const personholder == holderclass.of [person].create const studentholder == holderclass.of [student].create var stud : student var lærer : teacher var kurt : person % holderclass.of [student] *>holderclass.of [person] personholder studentholder personholder.indsæt[lærer ] stud studentholder.udtag stud.opkrævkopiafgift. NEL, Intropar

25 % er holderclass.of [person] *>holderclass.of [student]? studentholder personholder personholder.insæt[kurt] stud studentholder.udtag stud.opkrævkopiafgift

26 View const ptype type ptype function asstring [string] end ptype if elementtype *>ptype then ts (view ev (i) as ptype).asstring end if. NEL, Intropar

27 Builtins const AbstractType == immutable object AbstractType export getsignature const AbstractTypeSignature == immutable type AbstractTypeSignature function getsignature [Signature] end AbstractTypeSignature function getsignature [result : Signature] result AbstractTypeSignature end getsignature end AbstractType. NEL, Intropar

28 Any const Any == immutable object Any export getsignature const AnyType == type AnyType % no operations end AnyType function getsignature [result : Signature] result AnyType end getsignature end Any. NEL, Intropar

29 Node. NEL, Intropar

30 const Node == immutable object Node export getsignature, create, getstdin, getstdout const NodeType == type NodeType export operation getactivenodes [NodeList] export operation getallnodes [NodeList] export operation getnodeinformation [NodeListElement] export operation gettimeofday [Time] export operation delay [Time] export operation waituntil [Time] export operation getloadaverage [Real] export operation setnodeeventhandler [HandlerType] export operation removenodeeventhandler [HandlerType] export operation getstdin [InStream] export operation getstdout [OutStream] export function getlnn [Integer] export function getname [String] end NodeType function getsignature [result : Signature] result NodeType end getsignature function create [result : Node] result immutable object anode. end anode end create operation getstdin [result : InStream] end getstdin operation getstdout [result : OutStream] end getstdout end Node

31 NodeList const NodeListElement == immutable type NodeListElement function getthenode [Node] function getup [Boolean] function getincarnationtime [Time] function getlnn [Integer] end NodeListElement const NodeList == ImmutableVector.of [NodeListElement]. NEL, Intropar

32 OutStream const OutStreamType == type OutStreamType operation putchar [Character] operation putint [n : Integer, width : Integer] operation putreal [Real] operation putstring [String] operation flush operation close end OutStreamType (locate self ).getoutstream.putstring[ node out ]. NEL, Intropar

33 setoutstream import rtgaux from edbenv2 const so == object so process const mylnn == (locate self )$lnn stdout.putstring[ echo %Start\n ] stdout.flush stdin.close stdout.putstring[ echo calling rtgaux mylnn = ] stdout.putint[mylnn, 8] stdout.putstring[ \n ] stdout.flush rtgaux.setoutstream[stdout, mylnn] %runtimegenerator.settest[0] stdout.putstring[ echo % Slut rt init\n\n ] stdout.flush end process end so. NEL, Intropar

34 At køre Emerald setenv EMPLANE xx setenv EMERALDROOT /vol/projects3/intropar/emerald/bin setenv PATH $PATH:$EMERALDROOT""/bin:$EMERALDROOT""/bin/i686 ec thiho.m emx thiho.x. NEL, Intropar

35 Fejl og besværligheder 1. Maskiner går ned. 2. Maskiner kommer op. 3. Netværket går ned og op. 4. Netværket går delvist ned og Maskinerne opdeles i undernet. 5. Brugerprocesser går ned. 6. Brugerprocesser der ikke terminerer. 7. Brugerprocesser der flytter sig selv. 8. Maskinen med load balanceren går ned.. NEL, Intropar

36 Et distribueret eksempel 1. Killroy 2. Load balancer. NEL, Intropar

37 Mobilitet (artikel), Adressering locate forward broadcast. NEL, Intropar

38 X: address tag flags Object Data Area data pointer tag flags OID location code pointer data Object Data Area Y: address tag flags code pointer data Z: 32-bit data

39 Pointere Direkte pointere Alle pointere skal findes når noget flyttes. Templates. NEL, Intropar

40 Template const simpleobject == object simpleobject monitor var myself : Any simpleobject var name : String Emerald var i : Integer 17 operation GetMyName [n : String] n name end GetMyName. Concrete Type end monitor end simpleobject Data Area tag G R code pointer Operation Code monitor lock monitor queue 17 address Monitor1 Data 4 Pointer 2 Template Object Descriptor for simpleobject address Emerald. NEL, Intropar

41 Stak node α activation record of operation in C object C activation record of operation in B node β object B Process A Stack Segment 2 Process A Stack Segment 1 activation record of operation in A node α object A Process A Stack Base. NEL, Intropar