<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Thu, May 10, 2018 at 1:04 PM, Brian Goetz <span dir="ltr"><<a href="mailto:brian.goetz@oracle.com" target="_blank">brian.goetz@oracle.com</a>></span> wrote:</div><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div text="#000000" bgcolor="#FFFFFF">
    <tt>This might not help, but perhaps think of it as a compound
      keyword; "break switch" is not "break with an argument of switch",
      but a multi-word keyword itself.  <br></tt></div></blockquote><div><br></div><div>Well, then multi-word keywords are the thing that is novel and should require very strong justification. :-)</div><div><br></div><div>But no. I've gotta disagree with this: If we tell users that they can do "break while", "break for", "continue while", "continue for", and "break switch", no one's mental model will be that those are five different new keywords. There is a very obvious orthogonal separation between (first) what to do and (second) at what scope to do it. That's what I meant by "argument of".</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div text="#000000" bgcolor="#FFFFFF"><tt>Personally if I saw "break while", I think I'd immediately know
      what that means, and might even thank the author for being clear. </tt></div></blockquote><div><br></div><div>It's not bad.</div><div><br></div><div>Here's a quick tidbit from our codebase:</div><div><br></div><div>- Labeled break/continue is <i>unfathomably</i> rare -- a rough estimate is 0.07% of all break/continue statements. (<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">Just to be clear, no, we don't have any kind of style guide rule about avoiding the use of labels, or static analysis complaining about it, etc.)</span><br></div><div><br></div><div>- And even among this small 0.3%, in virtually every one of them the surrounding loops are of the same kind, so `break <keyword>` would not be applicable. <br></div><div><br></div><div><br></div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div text="#000000" bgcolor="#FFFFFF"><div><div class="h5">
    <div class="m_-5477076865366105268moz-cite-prefix">On 5/10/2018 3:57 PM, Kevin Bourrillion
      wrote:<br>
    </div>
    <blockquote type="cite">
      <div dir="ltr">I'm just going to say that naming a keyword as the
        argument of another keyword seems novel and unprecedented for
        Java, and as such I think should require pretty strong
        justification.
        <div><br>
        </div>
      </div>
      <div class="gmail_extra"><br>
        <div class="gmail_quote">On Thu, May 10, 2018 at 12:12 PM, Guy
          Steele <span dir="ltr"><<a href="mailto:guy.steele@oracle.com" target="_blank">guy.steele@oracle.com</a>></span>
          wrote:<br>
          <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
            <div class="m_-5477076865366105268HOEnZb">
              <div class="m_-5477076865366105268h5"><br>
                > On May 10, 2018, at 3:06 PM, Brian Goetz <<a href="mailto:brian.goetz@oracle.com" target="_blank">brian.goetz@oracle.com</a>>
                wrote:<br>
                > <br>
                > <br>
                >> I think these are both valid explanations, with
                different outcomes, but anyway it's fair to say that it
                would be confusing to have the latter perspective and
                then try to explain how a value break can get past a
                surrounding 'for' loop.<br>
                > <br>
                > One option is: you can't.  While I agree there is
                code that one might like to write that is made
                cumbersome by this, it's a valid option, and not one
                that is utterly terrible.<br>
                > <br>
                > Another option is to extend the break syntax along
                the lines of the proposed continue syntax.  Suppose for
                every continuable construct x (for, while, switch) we
                supported "continue x".  So for every breakable
                construct y we could support "break y".  If a for loop
                were enclosed in an expression switch, you could then
                say "break switch e".  Then<br>
                > <br>
                >    if (foo)<br>
                >        break;<br>
                >    else<br>
                >        break 3;<br>
                > <br>
                > becomes<br>
                > <br>
                >    if (foo)<br>
                >        break for;<br>
                >    else<br>
                >        break switch 3;<br>
                > <br>
                > and it is much more obvious what is going on.<br>
                <br>
              </div>
            </div>
            If we are willing to pile up keywords in that manner, an
            alternate possibility is to spell a value-returning break in
            a different way:<br>
            <br>
                    return switch <expression>;<br>
            <br>
            Then your example can become (I have added the implicit
            context):<br>
            <br>
                    switch (…) { case 17 -> {<br>
                            …<br>
                            for (…) {<br>
                               ...<br>
                               if (foo)<br>
                                   break;<br>
                               else<br>
                                   return switch 3;<br>
                            … }<br>
                        … }<br>
                    … }<br>
            <br>
            The additional advantage of this approach is that it
            completely eliminates the syntactic ambiguity between<br>
            <br>
                    break variableName;<br>
            <br>
            and<br>
            <br>
                    break labelName;<br>
            <br>
            Given that we think most occurrences of “return switch” (or
            “switch return”, take your pick) will be abbreviated by
            -> anyway, this might be an acceptable approach.<br>
            <br>
            You can then still choose to go ahead and also allow things
            like<br>
            <br>
                    break for;<br>
                    break switch;<br>
                    break while;<br>
                    continue for;<br>
                    continue switch;<br>
            <br>
            but that can be a separate decision; these become simply a
            way to avoid using statement labels.<br>
            <span class="m_-5477076865366105268HOEnZb"><font color="#888888"><br>
                —Guy<br>
                <br>
              </font></span></blockquote>
        </div>
        <br>
        <br clear="all">
        <div><br>
        </div>
        -- <br>
        <div class="m_-5477076865366105268gmail_signature" data-smartmail="gmail_signature">
          <div dir="ltr">
            <div>
              <div dir="ltr">
                <div>
                  <div dir="ltr">
                    <div style="line-height:1.5em;padding-top:10px;margin-top:10px;color:rgb(85,85,85);font-family:sans-serif"><span style="border-width:2px 0px 0px;border-style:solid;border-color:rgb(213,15,37);padding-top:2px;margin-top:2px">Kevin
                        Bourrillion |</span><span style="border-width:2px 0px 0px;border-style:solid;border-color:rgb(51,105,232);padding-top:2px;margin-top:2px"> Java
                        Librarian |</span><span style="border-width:2px 0px 0px;border-style:solid;border-color:rgb(0,153,57);padding-top:2px;margin-top:2px"> Google,
                        Inc. |</span><span style="border-width:2px 0px 0px;border-style:solid;border-color:rgb(238,178,17);padding-top:2px;margin-top:2px"> <a href="mailto:kevinb@google.com" target="_blank">kevinb@google.com</a></span></div>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>
    </blockquote>
    <br>
  </div></div></div>

</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div style="line-height:1.5em;padding-top:10px;margin-top:10px;color:rgb(85,85,85);font-family:sans-serif"><span style="border-width:2px 0px 0px;border-style:solid;border-color:rgb(213,15,37);padding-top:2px;margin-top:2px">Kevin Bourrillion |</span><span style="border-width:2px 0px 0px;border-style:solid;border-color:rgb(51,105,232);padding-top:2px;margin-top:2px"> Java Librarian |</span><span style="border-width:2px 0px 0px;border-style:solid;border-color:rgb(0,153,57);padding-top:2px;margin-top:2px"> Google, Inc. |</span><span style="border-width:2px 0px 0px;border-style:solid;border-color:rgb(238,178,17);padding-top:2px;margin-top:2px"> <a href="mailto:kevinb@google.com" target="_blank">kevinb@google.com</a></span></div></div></div></div></div></div></div>
</div></div>