Saturday, December 31, 2016

Re: 'maxfuncdepth' ignored

2016-12-30 20:09 GMT+03:00 Brett Stahlman <brettstahlman@gmail.com>:
> Consider the following recursive user function...
>
> fu! Fun(count)
> if a:count > 0
> call Fun(a:count - 1)
> endif
> endfu
>
> :h 'maxfuncdepth' describes the option's purpose as follows:
>
> Maximum depth of function calls for user functions. This normally
> catches endless recursion. When using a recursive function with
> more depth, set 'maxfuncdepth' to a bigger number.
>
> So I would expect to be able to make the following recursive call with no error:
> :set maxfuncdepth=1000
> :call Fun(500)
>
> But I get the following error after slightly less than 200 recursive calls:
> E169: Command too recursive
>
> The documentation for E169 states the following:
>
> This happens when an Ex command executes an Ex command that executes an Ex
> command, etc. This is only allowed 200 times. When it's more there probably
> is an endless loop. Probably a |:execute| or |:source| command is involved.
>
> It's as though the :call (Ex command) is triggering the error long
> before the number of calls to the user function Fun() has reached
> 'maxfuncdepth'. But if this is the way it's supposed to work, what's
> the point of 'maxfuncdepth'? Don't all calls to user functions involve
> an Ex command (since both `call' and `let' are Ex commands)? Is there
> a way to permit more than 200 recursive calls to Fun() without
> triggering the error?

I tried lambdas, but they also catch this error due to the way they
are implemented. Unlike (until you consider their internal
implementation) lambdas regular functions are lists of Ex commands, so
this is not surprising. Note that by default &maxfuncdepth is 100
which is lesser then 200.

>
> Thanks,
> Brett Stahlman
>
> --
> --
> You received this message from the "vim_use" maillist.
> Do not top-post! Type your reply below the text you are replying to.
> For more information, visit http://www.vim.org/maillist.php
>
> ---
> You received this message because you are subscribed to the Google Groups "vim_use" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to vim_use+unsubscribe@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.

--
--
You received this message from the "vim_use" maillist.
Do not top-post! Type your reply below the text you are replying to.
For more information, visit http://www.vim.org/maillist.php

---
You received this message because you are subscribed to the Google Groups "vim_use" group.
To unsubscribe from this group and stop receiving emails from it, send an email to vim_use+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

No comments: