Re: [friam] Classification of actor languages
"Mark S. Miller" <[email protected]> Mon, 16 Feb 2015 12:50:23 -0800
| Newsgroups | gmane.comp.lang.e.general |
|---|---|
| Message-ID | <CABHxS9jFEOumMu2zmmjOCWfkza7J4-JQFrSbPcyB5Xb1pkSpgQ@mail.gmail.com> |
--===============4561426005785213842== Content-Type: multipart/alternative; boundary=20cf3010ebdd35a08b050f3abc61 --20cf3010ebdd35a08b050f3abc61 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable It is not at all obvious to me what you even mean by these terms. Can you define them in terms of, for example, the Hewitt-Baker Actor laws, the Clinger Actor semantics, or something equally foundational? As for conventional use of these terms, they mean many subtly different things in different contexts, so it is again not obvious precisely what you even intend to mean. For example, the main context I would expect to borrow from, Java and C#, you explicitly say do not mean the same thing as you by "interface". On Mon, Feb 16, 2015 at 12:46 PM, Carl Hewitt <[email protected]> wrote: > Hi Mark, > > > > It is obvious that an Actor needs to be able to implement multiple > interfaces. > > However, it is important to avoid mistakes that were made in Java and C#. > > For example, > > =C2=B7 It must be possible to have the **same** message receiver > signature in > > two different interfaces implemented by the same Actor. > > =C2=B7 It must not be possible **externally** to cast an address fo= r one > interface > > to an address for another interface. > > > > Cheers, > > Carl > > > > *From:* friam-/[email protected] [mailto:friam-/[email protected]] > *Sent:* Monday, February 16, 2015 12:38 > *To:* friam > > *Cc:* Discussion of E and other capability languages > *Subject:* Re: [friam] Classification of actor languages > > > > Carl, what do you mean by "interface" here? It doesn't sound like any > foundational concept I know of from my long study of Actors. > > > > > > > > On Mon, Feb 16, 2015 at 12:34 PM, Carl Hewitt <[email protected]> wrote: > > Hi Tom, > > > > It should **not** be the case that having an address for > > an interface to an Actor automatically enables sending messages > > to other interfaces of the Actor. The only way to obtain > > addresses for other interfaces is for them to be communicated > > in messages by the Actor. > > > > In this respect, Java and C# are **not** proper Actor programming > languages > > because it is possible to **externally** cast from one interface of an > Actor to another :-( > > > > Cheers, > > Carl > > > > > > *From:* friam-/[email protected] [mailto:friam-/[email protected]] *On Behalf > Of *Tom Van Cutsem > *Sent:* Monday, February 16, 2015 12:24 > *To:* friam-/[email protected] > *Cc:* Discussion of E and other capability languages > *Subject:* Re: [friam] Classification of actor languages > > > > Hi Carl, > > > > 2015-02-14 1:19 GMT+01:00 Carl Hewitt <[email protected]>: > > Of course, an Actor can implement multiple interfaces. > > > > I am wondering how a =E2=80=9Cfacet=E2=80=9D relates to an interface. > > > > Indeed, an actor can implement multiple interfaces, but this typically > means that anyone having a reference to the actor can send any message fr= om > the union of all interface methods. By contrast, in a vat with multiple > facets, a reference to a facet provides access to only the methods expose= d > by that facet. Thus, facets make it easier to restrict authority. > > > > Of course, one could encode facets in a pure actor model, by passing a > token designating the facet as part of the message. The actor can be > programmed to dispatch the message to an internal object only if the toke= n > matches. But this would be an encoding of the vat model in a pure actor > model. > > > > Cheers, > > Tom > > -- > You received this message because you are subscribed to the Google Groups > "friam" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to friam+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/[email protected] > To post to this group, send email to friam-/JYPxA39Uh5TLH3MbocFF+G/[email protected] > Visit this group at http://groups.google.com/group/friam. > For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "friam" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to friam+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/[email protected] > To post to this group, send email to friam-/JYPxA39Uh5TLH3MbocFF+G/[email protected] > Visit this group at http://groups.google.com/group/friam. > For more options, visit https://groups.google.com/d/optout. > > > > > > -- > > Cheers, > --MarkM > > -- > You received this message because you are subscribed to the Google Groups > "friam" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to friam+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/[email protected] > To post to this group, send email to friam-/JYPxA39Uh5TLH3MbocFF+G/[email protected] > Visit this group at http://groups.google.com/group/friam. > For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "friam" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to friam+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/[email protected] > To post to this group, send email to friam-/JYPxA39Uh5TLH3MbocFF+G/[email protected] > Visit this group at http://groups.google.com/group/friam. > For more options, visit https://groups.google.com/d/optout. > --=20 Cheers, --MarkM --20cf3010ebdd35a08b050f3abc61 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr">It is not at all obvious to me what you even mean by these= terms. Can you define them in terms of, for example, the Hewitt-Baker Acto= r laws, the Clinger Actor semantics, or something equally foundational?<div= ><br></div><div>As for conventional use of these terms, they mean many subt= ly different things in different contexts, so it is again not obvious preci= sely what you even intend to mean. For example, the main context I would ex= pect to borrow from, Java and C#, you explicitly say do not mean the same t= hing as you by "interface".</div><div><br></div><div><br></div><d= iv><br></div><div><br></div></div><div class=3D"gmail_extra"><br><div class= =3D"gmail_quote">On Mon, Feb 16, 2015 at 12:46 PM, Carl Hewitt <span dir=3D= "ltr"><<a href=3D"mailto:[email protected]" target=3D"_blank">hewitt@ir= obust.org</a>></span> wrote:<br><blockquote class=3D"gmail_quote" style= =3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div lang=3D"EN-US" link=3D"blue" vlink=3D"purple"> <div> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black">Hi Mark,<u></u><u></u></sp= an></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black"><u></u>=C2=A0<u></u></span= ></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black">It is obvious that an Acto= r needs to be able to implement multiple interfaces.<u></u><u></u></span></= p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black">However, it is important t= o avoid mistakes that were made in Java and C#.<u></u><u></u></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black">For example,<u></u><u></u>= </span></p> <p><u></u><span style=3D"font-size:11.0pt;font-family:Symbol;color:black"><= span>=C2=B7<span style=3D"font:7.0pt "Times New Roman"">=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 </span></span></span><u></u><span style=3D"font-size:11.0pt;font-family:&qu= ot;Microsoft Sans Serif",sans-serif;color:black">It must be possible t= o have the *<b>same</b>* message receiver signature in <u></u><u></u></span></p> <p><span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif&q= uot;,sans-serif;color:black">two different interfaces implemented by the sa= me Actor.<u></u><u></u></span></p> <p><u></u><span style=3D"font-size:11.0pt;font-family:Symbol;color:black"><= span>=C2=B7<span style=3D"font:7.0pt "Times New Roman"">=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 </span></span></span><u></u><span style=3D"font-size:11.0pt;font-family:&qu= ot;Microsoft Sans Serif",sans-serif;color:black">It must not be possib= le *<b>externally</b>* to cast an address for one interface<u></u><u></u></= span></p> <p><span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif&q= uot;,sans-serif;color:black">to an address for another interface.<u></u><u>= </u></span></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black"><u></u>=C2=A0<u></u></span= ></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black">Cheers,<u></u><u></u></spa= n></p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black">Carl<u></u><u></u></span><= /p> <p class=3D"MsoNormal"><span style=3D"font-size:11.0pt;font-family:"Mi= crosoft Sans Serif",sans-serif;color:black"><u></u>=C2=A0<u></u></span= ></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><b><span style=3D"font-si= ze:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span= style=3D"font-size:11.0pt;font-family:"Calibri",sans-serif"> <a = href=3D"mailto:friam-/[email protected]" target=3D"_blank">friam@googlegroups= .com</a> [mailto:<a href=3D"mailto:friam-/[email protected]" target=3D"_blank= ">friam-/[email protected]</a>] <br> <b>Sent:</b> Monday, February 16, 2015 12:38<br> <b>To:</b> friam</span></p><div><div class=3D"h5"><br> <b>Cc:</b> Discussion of E and other capability languages<br> <b>Subject:</b> Re: [friam] Classification of actor languages<u></u><u></u>= </div></div><p></p><div><div class=3D"h5"> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><u></u>=C2=A0<u></u></p> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in">Carl, what do you mean by= "interface" here? It doesn't sound like any foundational con= cept I know of from my long study of Actors.<u></u><u></u></p> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><u></u>=C2=A0<u></u></p> </div> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><u></u>=C2=A0<u></u></p> </div> </div> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><u></u>=C2=A0<u></u></p> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in">On Mon, Feb 16, 2015 at 1= 2:34 PM, Carl Hewitt <<a href=3D"mailto:[email protected]" target=3D"_b= lank">[email protected]</a>> wrote:<u></u><u></u></p> <blockquote style=3D"border:none;border-left:solid #cccccc 1.0pt;padding:0i= n 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"> <div> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">Hi Tom,</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">It should *<b>not</b>* be the case that having an= address for </span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">an interface to an Actor automatically enables se= nding messages</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">to other interfaces of the Actor. The only way to= obtain</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">addresses for other interfaces is for them to be = communicated</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">in messages by the Actor.</span><u></u><u></u></p= > <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">In this respect, Java and C# are *<b>not</b>* pro= per Actor programming languages</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">because it is possible to *<b>externally</b>* cas= t from one interface of an Actor to another :-(</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">Cheers,</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">Carl</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:.5in"> <span style=3D"font-size:11.0pt;font-family:"Microsoft Sans Serif"= ;,sans-serif;color:black">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> <b><span style=3D"font-size:11.0pt;font-family:"Calibri",sans-ser= if">From:</span></b><span style=3D"font-size:11.0pt;font-family:"Calib= ri",sans-serif"> <a href=3D"mailto:friam-/[email protected]" target=3D"_blank">friam@googlegro= ups.com</a> [mailto:<a href=3D"mailto:friam-/[email protected]" target=3D"_bl= ank">friam-/[email protected]</a>] <b>On Behalf Of </b>Tom Van Cutsem<br> <b>Sent:</b> Monday, February 16, 2015 12:24<br> <b>To:</b> <a href=3D"mailto:friam-/[email protected]" target=3D"_blank">fria= [email protected]</a><br> <b>Cc:</b> Discussion of E and other capability languages<br> <b>Subject:</b> Re: [friam] Classification of actor languages</span><u></u>= <u></u></p> <div> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> =C2=A0<u></u><u></u></p> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> Hi Carl,<u></u><u></u></p> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> =C2=A0<u></u><u></u></p> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> 2015-02-14 1:19 GMT+01:00 Carl Hewitt <<a href=3D"mailto:hewitt@irobust.= org" target=3D"_blank">[email protected]</a>>:<u></u><u></u></p> <blockquote style=3D"border:none;border-left:solid #cccccc 1.0pt;padding:0i= n 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-= bottom:5.0pt"> <div> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> <span style=3D"font-size:11.0pt;font-family:"Calibri",sans-serif;= color:#1f497d">Of course, an Actor can implement multiple interfaces.</span= ><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> <span style=3D"font-size:11.0pt;font-family:"Calibri",sans-serif;= color:#1f497d">=C2=A0</span><u></u><u></u></p> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> <span style=3D"font-size:11.0pt;font-family:"Calibri",sans-serif;= color:#1f497d">I am wondering how a =E2=80=9Cfacet=E2=80=9D relates to an i= nterface.</span><u></u><u></u></p> </div> </div> </blockquote> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> =C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> Indeed, an actor can implement multiple interfaces, but this typically mean= s that anyone having a reference to the actor can send any message from the= union of all interface methods. By contrast, in a vat with multiple facets= , a reference to a facet provides access to only the methods exposed by that facet. Thus, facets make it eas= ier to restrict authority.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> =C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> Of course, one could encode facets in a pure actor model, by passing a toke= n designating the facet as part of the message. The actor can be programmed= to dispatch the message to an internal object only if the token matches. B= ut this would be an encoding of the vat model in a pure actor model.<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> =C2=A0<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> Cheers,<u></u><u></u></p> </div> <div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> Tom<u></u><u></u></p> </div> </div> </div> </div> <p class=3D"MsoNormal" style=3D"margin-left:1.0in"> -- <br> You received this message because you are subscribed to the Google Groups &= quot;friam" group.<br> To unsubscribe from this group and stop receiving emails from it, send an e= mail to <a href=3D"mailto:friam+unsubscribe-/[email protected]" target=3D"_blank">fri= am+unsubscribe-/[email protected]</a>.<br> To post to this group, send email to <a href=3D"mailto:[email protected]= om" target=3D"_blank"> friam-/[email protected]</a>.<br> Visit this group at <a href=3D"http://groups.google.com/group/friam" target= =3D"_blank"> http://groups.google.com/group/friam</a>.<br> For more options, visit <a href=3D"https://groups.google.com/d/optout" targ= et=3D"_blank"> https://groups.google.com/d/optout</a>.<u></u><u></u></p> </div> </div> </div> </div> <div> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in">-- <br> You received this message because you are subscribed to the Google Groups &= quot;friam" group.<br> To unsubscribe from this group and stop receiving emails from it, send an e= mail to <a href=3D"mailto:friam+unsubscribe-/[email protected]" target=3D"_blank">fri= am+unsubscribe-/[email protected]</a>.<br> To post to this group, send email to <a href=3D"mailto:[email protected]= om" target=3D"_blank"> friam-/[email protected]</a>.<br> Visit this group at <a href=3D"http://groups.google.com/group/friam" target= =3D"_blank"> http://groups.google.com/group/friam</a>.<br> For more options, visit <a href=3D"https://groups.google.com/d/optout" targ= et=3D"_blank"> https://groups.google.com/d/optout</a>.<u></u><u></u></p> </div> </div> </blockquote> </div> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><br> <br clear=3D"all"> <u></u><u></u></p> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in"><u></u>=C2=A0<u></u></p> </div> <p class=3D"MsoNormal" style=3D"margin-left:.5in">-- <u></u><u></u></p> <div> <p class=3D"MsoNormal" style=3D"margin-left:.5in">=C2=A0 =C2=A0 Cheers,<br> =C2=A0 =C2=A0 --MarkM<u></u><u></u></p> </div> </div> <p class=3D"MsoNormal" style=3D"margin-left:.5in">-- <br> You received this message because you are subscribed to the Google Groups &= quot;friam" group.<br> To unsubscribe from this group and stop receiving emails from it, send an e= mail to <a href=3D"mailto:friam+unsubscribe-/[email protected]" target=3D"_blank">fri= am+unsubscribe-/[email protected]</a>.<br> To post to this group, send email to <a href=3D"mailto:[email protected]= om" target=3D"_blank">friam-/[email protected]</a>.<br> Visit this group at <a href=3D"http://groups.google.com/group/friam" target= =3D"_blank">http://groups.google.com/group/friam</a>.<br> For more options, visit <a href=3D"https://groups.google.com/d/optout" targ= et=3D"_blank">https://groups.google.com/d/optout</a>.<u></u><u></u></p> </div></div></div> </div><div class=3D"HOEnZb"><div class=3D"h5"> <p></p> -- <br> You received this message because you are subscribed to the Google Groups &= quot;friam" group.<br> To unsubscribe from this group and stop receiving emails from it, send an e= mail to <a href=3D"mailto:friam+unsubscribe-/[email protected]" target=3D"_bl= ank">friam+unsubscribe-/[email protected]</a>.<br> To post to this group, send email to <a href=3D"mailto:[email protected]= om" target=3D"_blank">friam-/[email protected]</a>.<br> Visit this group at <a href=3D"http://groups.google.com/group/friam" target= =3D"_blank">http://groups.google.com/group/friam</a>.<br> For more options, visit <a href=3D"https://groups.google.com/d/optout" targ= et=3D"_blank">https://groups.google.com/d/optout</a>.<br> </div></div></blockquote></div><br><br clear=3D"all"><div><br></div>-- <br>= <div class=3D"gmail_signature">=C2=A0 =C2=A0 Cheers,<br>=C2=A0 =C2=A0 --Mar= kM</div> </div> --20cf3010ebdd35a08b050f3abc61-- --===============4561426005785213842== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ e-lang mailing list [email protected] http://www.eros-os.org/mailman/listinfo/e-lang --===============4561426005785213842==--