From: David Menendez On Thu, Jun 11, 2009 at 1:53 PM, Sittampalam, Ganesh wrote:

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David Menendez wrote:

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On Thu, Jun 11, 2009 at 9:37 AM, Sittampalam, Ganesh wrote:

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The main issue (IMO) is that do notation uses (>>) in the desugaring, which in turn means that it supports statements that just throw away not () results.

How is that a problem? The whole *point* of (>>) is that it discards unneeded return values.

I think we should avoid having syntax that implicitly does this. So

do getLine   return 3

should be banned, and users should be forced to write something like

do getLine >> ignore   return 3

or

do _ <- getLine   return 3

Ganesh

Again, why do you think that? I much prefer the current syntax.

IMO this is a tricky issue. On the one hand, it's clear with do-notation that the result of a line is being ignored because it isn't explicitly handled. On the other hand, this strikes me as antithetical to the spirit of the language. I somewhat grudgingly agree with Henning and Ganesh that the syntax should prevent accidentally ignoring values when possible. I say grudgingly because I also prefer the current syntax. although if it were going to change my next favorite option is do ignore getLine return 3 John