<div dir="ltr"><div><div>Thanks, I interpret layout as you say, but with the aim of preserving valid spacing if syntax elements are moved around as a result of AST modifications. My implementation flags those points, such as the contents of a let .. in, or a do expression.<br><br></div>In terms of ghc-exactprint, I actually think the technique I am using of converting all the original absolute locations to relative ones, editing the AST and then outputting it should be transferrable to haskell-src-exts too.<br><br></div>Alan<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Mar 10, 2015 at 8:05 PM, Andrew Gibiansky <span dir="ltr"><<a href="mailto:andrew.gibiansky@gmail.com" target="_blank">andrew.gibiansky@gmail.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">Just to be clear, I *think* layout rules don't apply here at all, actually. <div><br></div><div>If I understand correctly, "layout" has to do with turning spacing into braces and semicolons. A new line is a semicolon. A brace group is inserted around things that are aligned where a brace group actually makes sense.</div><div><br></div><div>e.g. </div><div><br></div><div><font face="monospace, monospace">let x = y</font></div><div><font face="monospace, monospace"> y = z </font></div><div><font face="monospace, monospace"> in ...</font></div><div><br></div><div>gets turned into roughly</div><div><br></div><div><font face="monospace, monospace">let { x = y</font></div><div><font face="monospace, monospace"> ; y = z</font></div><div><font face="monospace, monospace"> } in ...</font></div><div><br></div><div>if-then-else however is just an expression, like a ternary operator, so it doesn't need any semicolons or braces. So layout is unrelated, except for the issue of `do` blocks inserting semicolons into `if-then-else` groups (and that's what DoAndIfThenElse fixes).</div><span class="HOEnZb"><font color="#888888"><div><br></div><div>-- Andrew</div></font></span><div><br></div><div>PS. I am very glad someone is working on ghc-exactprint. It's a really important step in developing better Haskell tooling, imho. Doing that sort of thing right now with haskell-src-exts right now is a real pain (see half of the closed issues on hindent... about how it doesn't preserve formatting in many places.)</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Tue, Mar 10, 2015 at 9:25 AM, Alan & Kim Zimmerman <span dir="ltr"><<a href="mailto:alan.zimm@gmail.com" target="_blank">alan.zimm@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr"><div><div>Ok, adding a do does make a difference. More complexity.<br><br></div>Thanks<span><font color="#888888"><br></font></span></div><span><font color="#888888"> Alan<br></font></span></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Mar 10, 2015 at 6:06 PM, Brandon Allbery <span dir="ltr"><<a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.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 class="gmail_extra"><div class="gmail_quote"><span>On Tue, Mar 10, 2015 at 12:01 PM, Alan & Kim Zimmerman <span dir="ltr"><<a href="mailto:alan.zimm@gmail.com" target="_blank">alan.zimm@gmail.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>I am working on ghc-exactprint, and need to flag points where layout must be preserved, and considering the `if` statement.<br><br>My understanding of the layout rules for if then else is that the `then` has to start more to the right than the `if`.<br></div></div></div></div></blockquote><div><br></div></span><div>I believe you are looking for DoAndIfThenElse.</div><span><font color="#888888"><div><br></div></font></span></div><span><font color="#888888">-- <br><div><div dir="ltr"><div>brandon s allbery kf8nh sine nomine associates</div><div><a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a> <a href="mailto:ballbery@sinenomine.net" target="_blank">ballbery@sinenomine.net</a></div><div>unix, openafs, kerberos, infrastructure, xmonad <a href="http://sinenomine.net" target="_blank">http://sinenomine.net</a></div></div></div>
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