<div dir="ltr">Hi Karim,<div><br></div><div>I wasn't aware before how this was supposed to work, but it appears ChucK treats a literal array as an array of the most specific type that encompasses all of its elements. Thats why an array of [SinOsc, SqrOsc, TriOsc] automatically turns into Osc[]. </div><div><br></div><div>On the other hand it is indeed not possible to use an array as an array of its supertype. One reason for this is that x @=> A[0] should work for any UGen x and UGen[] A but would be invalid if A is actually Osc[]. This kind of error would be only detected at run-time and not at compile-time, breaking compile-time type safety. </div><div><br></div><div>In your specific case you could take advantage of the first fact and do something this:</div><div><br></div><div><span style="font-size:12.8px">[s0$UGen, s1, s2] @=> UGen A[];</span><br style="font-size:12.8px"></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">But this doesn't generalize beyond determining the type of the array when it is defined literally. </span></div><div><br></div><div>spencer</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jan 4, 2017 at 6:59 AM, Karim Sumun <span dir="ltr"><<a href="mailto:sumun@pobox.com" target="_blank">sumun@pobox.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div><div>Given the following declarations:<br><br></div>SinOsc s0;<br></div>SqrOsc s1;<br></div>TriOsc s2;<br><br></div>The following gives an error:<br><br></div>[s0, s1, s2] @=> UGen A[];<br>$ ... cannot resolve operator '=>' on types 'Osc[]' and 'UGen[]'...<br><br></div>But the following works fine:<br></div>[s0, s1, s2] @=> Osc A[];<br><br><br></div>It is not a problem, but would like to understand this behaviour. It would seem that assigning to UGen[] would be ok because it looks like a superclass of Osc[].<br><br></div>Aaah! Is this to do with co/contra-variance?<br></div>
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<br></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><div dir="ltr"><div style="font-family:arial;font-size:small"><div>Spencer Salazar<br></div><div>Doctoral Candidate</div><div>Center for Computer Research in Music and Acoustics</div><div>Stanford University</div><div><br></div><div><a href="mailto:spencer@ccrma.stanford.edu" target="_blank">spencer@ccrma.stanford.edu</a></div><div></div><div>+1 831.277.4654<br></div><div><a href="https://ccrma.stanford.edu/~spencer/" style="color:rgb(17,85,204)" target="_blank">https://ccrma.stanford.edu/~spencer/</a><br></div><div><br></div></div></div></div></div></div></div></div></div></div>
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