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<p>Hi,</p>
<p><br>
</p>
<p>Someone who's written more could well point out this is heresy but I find verify* functions very convenient to write if I make them an Erlang assertion. eg:</p>
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<p>isone(A)-><br>
A = 1.<br>
istwo(A) -><br>
A = 2.<br>
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<p><br>
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<p>Compare that with a case A of.. for each function. Much more complex verifies still work very well with a binary pattern match. Then I can write a verify like this:</p>
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</p>
<p>verify(Data) -></p>
<p></p>
<div> try<br>
isone(Data),<br>
istwo(Data) % As many verify functions as needed here<br>
of<br>
_ -> true<br>
catch<br>
error:{badmatch, _} -> false<br>
end.<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> erlang-questions-bounces@erlang.org <erlang-questions-bounces@erlang.org> on behalf of qp <quantumpotato@gmail.com><br>
<b>Sent:</b> Tuesday, 6 December 2016 10:16:16 AM<br>
<b>To:</b> Erlang/OTP discussions<br>
<b>Subject:</b> [erlang-questions] Idiomatically handling multiple validation checks</font>
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<div>Hi, I am new to Erlang and wrote this code for validating that the Name, Action & Target atoms passed in to validRequest are all valid.<br>
<br>
validRequest(valid, valid, Target) -><br>
case validName(Target) of<br>
true -> true;<br>
false -> false<br>
end;<br>
validRequest(valid, Action, Target) -><br>
case validAction(Action) of<br>
true -> validRequest(valid, valid, Target);<br>
false -> false<br>
end;<br>
validRequest(Name, Action, Target) -><br>
case validName(Name) of<br>
true -> validRequest(valid, Action, Target);<br>
false -> false<br>
end.<br>
<br>
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I've since refactored into<br>
<br>
validRequest(Name, Action, Target) -><br>
validName(Name) and validAction(Action) and validName(Target). <br>
<br>
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I'm curious what a more idiomatic way of writing this would be? I've seen a mix of styles using booleans for return values and tuples, with errors listed. I don't think that's needed here but I'm just curious how you would handle multiple validation checks,
especially if they were more complicated than this example. Thank you!<br>
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