<div dir="ltr">Swift already is an unmanaged language, and is far closer to C++ than Java. There is no equivalent to the CLR or JVM and it is trivially easy to call into C code or the unsafe APIs and do nearly anything that C can do with regard to direct access to memory.<div><br></div><div>The force-unwrap operator was never intended to model a Java-style runtime exception. Instead, it is an assertion which indicates a programmer logic error. The preferred way to handle an optional at runtime has always been to use the conditional-unwrapping functionality the language offers. The correct way to report errors at runtime that aren't due to programmer error is through the do-try-catch mechanism. Pervasive, unnecessary use of '!' is a project management and/or developer competence issue, and not something the language should go out of its way to fix.</div><div><br></div><div>Sugaring 'if let' for programmer convenience is something on the commonly rejected proposals list: <a href="https://github.com/apple/swift-evolution/blob/master/commonly_proposed.md">https://github.com/apple/swift-evolution/blob/master/commonly_proposed.md</a></div><div><br></div><div>Regards,</div><div>Austin</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Mar 6, 2017 at 6:27 PM, Elijah Johnson via swift-evolution <span dir="ltr"><<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">Additionally, not discarding previous comments, one way the language could be improved is by replacing (or rather augmenting) optional binding with a faster syntax.</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">ex.</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">func test( name : String?, name2 :String? ){</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"> name! , name2! {</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><span class="m_2492479024697317942Apple-tab-span" style="white-space:pre-wrap"> </span>// inside this block, “name” and “name2” are non-optional</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"> } else {</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"> // no forced unwrapping, just optional else case</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"> }</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">}</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">Whereas the alternative (current optional binding), requires a re-definition of variables and an additional “if” operator. Besides the extra characters involved in typing and reading it, usually variables have specific names that the user does not want to augument.</div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><div id="m_2492479024697317942bloop_customfont" style="margin:0px">func test( name : String?, name2 :String? ){</div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"> if let nameUnwrapped = name , let name2Unwrapped = name2 {</div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"><br></div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"> } else {</div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"> }</div><div id="m_2492479024697317942bloop_customfont" style="margin:0px">}</div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"><br></div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"><div id="m_2492479024697317942bloop_customfont" style="margin:0px">func test( name : String?, name2 :String? ){</div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"> guard let nameUnwrapped = name , let name2Unwrapped = name2 else {</div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"><br></div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"> }</div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"><br></div><div id="m_2492479024697317942bloop_customfont" style="margin:0px">}</div></div><div id="m_2492479024697317942bloop_customfont" style="margin:0px"><br></div><div id="m_2492479024697317942bloop_customfont" style="margin:0px">The fact that we don’t need a “nameUnwrapped” variable (which is unsightly and requires refractoring) is one thing that still makes forced unwrapping still very much a necessary or common part of Swift coding, even where it could be replaced with optional binding.</div></div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div><div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div> <br> <div id="m_2492479024697317942bloop_sign_1488852857050308864" class="m_2492479024697317942bloop_sign"></div> <br><p class="m_2492479024697317942airmail_on">On March 6, 2017 at 7:20:40 PM, Elijah Johnson (<a href="mailto:ejrx7753@gmail.com" target="_blank">ejrx7753@gmail.com</a>) wrote:</p> <blockquote type="cite" class="m_2492479024697317942clean_bq"><span><div style="word-wrap:break-word"><div></div><div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
Hi,</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<br></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
I’ve been recently considering Swift on the server-side, and there
came up the question, “what happens when a null optional is
forcibly unwrapped?” and the answer was clearly that not only would
the request crash, but the entire server would also crash, since
the server itself is/would be also written in Swift.</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<br></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
I think that this highlights serveral weaknesses in Swift’s “null
safety” attempts. The first is that there needs to be a way to
isolate blocks of code so that a “null pointer exception” does not
crash the system. I think it is fair to say, in the language of
Java, that these are really “runtime exceptions” and for some
reason are being treated as segmentation faults would be in C/C++.
In my opinion, the existence of these things has the ability to
bring Swift down below Java and closer to an unamanged language.
Not really sure why it would ever be desireable, but in terms of
server-side programming, it is definitely a serious issue.</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<br></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
Secondly, Swift’s “null safety” is really completely undermined by
these “force-unwrap” errors. I agree with the usage of new language
features like guard, optional binding, etc to remove a null value,
but I see this force-unwrap as extremely pervasive for a lot of
reasons:</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<br></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
1. When porting code from a C style language to Swift, force-unwrap
is needed to make the code work without refractoring.</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
2. XCode itself reccomends this operator and when it is used to
satisfy a requirement, then it can be left in the code</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
3. Some styles of coding just can’t work without
force-unwrap.</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<br></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
I don’t think the logic of making the consequences extreme for
making a mistake are a rational for making better coders. In fact,
I personally see the “force-unwrap” operator having very great
potential usage as a deliberate assertion exception - the
programmer demands that a certain value be non-null for execution
to continue, only there should be a proper scope and context where
these exceptions can propogate to. On debug modes, one might want
it to pause on the line, but for other uses, it should be caught
IMO - on regular code by the user, and inside dispatch blocks by
the queue itself. For a multithreaded app or server to exit, the
user should have to explicitly write exit(0), isn’t this the goal
of a managed language? Maybe in some cases, Apple will want the
program to crash, but if Swift is given an audience not just with
Apple hardware, then it should have more flexibility IMO.</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<br></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
Elijah</div>
<div id="m_2492479024697317942bloop_sign_1488843525920942080" class="m_2492479024697317942bloop_sign"></div>
</div></div></span></blockquote></div>
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<br></blockquote></div><br></div>