[Python-Dev] Wishlist: dowhile

Mon Jun 13 16:16:53 CEST 2005

On Monday 13 June 2005 08:07, Nick Coghlan wrote:
> Raymond Hettinger wrote:
> > [BJörn Lindqvist]
> >
> >>I would like to have do-while's like this:
> >>
> >>do:
> >>    <body>
> >>    until <cond>
> >>
> >>But I'm sure that has problems too.
> >
> > That looks nice to me.
>
> And this could easily be extended to allow code both before and after
> the 'until', giving a fully general loop:
>
>    do:
>        <body-1-or-more-times>
>        until <cond>
>        <body-0-or-more-times>
>    else:
>        <on-natural-loop-exit>
>
> In fact, this would simply be giving "looks like executable
> pseudocode" syntactic sugar for the current 'do-until' workarounds:
>
>    while 1:
>      <body-1-or-more-times>
>      if <cond>:
>          <on-natural-loop-exit>
>          break
>      <body-0-or-more-times>

Yet another way to spell this would be make the default for the while 
statement be true so the 1 could be omitted and then add a condition to 
break.  

    while:
      <body-1-or-more-times>
      break <cond>:
          <on-natural-loop-exit>
      <body-0-or-more-times>

 I think this would be feature creep. It complicates the language for a very 
small gain. While the added syntax would be intuitive, it only saves a line 
or two over the existing syntax. 