<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
It is for the very annoying reason that in order for Error to be a
monad it has to implement the "fail" method, which means it has to know
how to turn an arbitrary string into a value of your error type.<br>
<br>
Cheers,<br>
Greg<br>
<br>
On 07/27/10 15:32, Gerald Gutierrez wrote:
<blockquote
cite="mid:AANLkTiktveTkZm0dL-LrTuV20YkiwrAaOHRdOf4OucNu@mail.gmail.com"
type="cite"><br>
Reading the Control.Monad.Error documentation, I see that the Error
class has noMsg and strMsg as its only two functions. <br>
<br>
Now, I understand that you can define your own Error instances such as
in example 1 of the documentation, so why the need to always support
strings via noMsg/strMsg ? What uses these? And if in my code, I will
never throw an error with a string, am I supposed to implement these
functions and then ignore them?<br>
<style type="text/css">#avg_ls_inline_popup { position:absolute; z-index:9999; padding: 0px 0px; margin-left: 0px; margin-top: 0px; width: 240px; overflow: hidden; word-wrap: break-word; color: black; font-size: 10px; text-align: left; line-height: 13px;}</style>
<pre wrap="">
<fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
Haskell-Cafe mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Haskell-Cafe@haskell.org">Haskell-Cafe@haskell.org</a>
<a class="moz-txt-link-freetext" href="http://www.haskell.org/mailman/listinfo/haskell-cafe">http://www.haskell.org/mailman/listinfo/haskell-cafe</a>
</pre>
</blockquote>
<br>
</body>
</html>