Re: Help converting function to Vim9 script
On 2021-07-07, lgc wrote: >> Any idea what would be the best way to convert the snippet above? > > Move the `i` variable in the script-local namespace. Thanks for the thorough explanation. For now, I am keeping a function instead of a def. But, as you say: > FWIW, I would still refactor the code in Vim9. Mainly because of type > checking, and for better readability. I'll likely do that, using a script variable as you suggest. Thanks, Life. -- -- 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+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/vim_use/sc6u3t%2411j9%241%40ciao.gmane.io.
Re: Help converting function to Vim9 script
> I try not to use global variables within functions. Is there an
> alternative enabling non-use of global variables?
Yes, use block-local, function-local, or script-local variables. Those
don't need any explicit scope.
> Also, I thought the new Vim9 Vimscript was getting rid of the need for
> g: and l: and a: etc. That stuff used to kill my brain.
`l:` and `a:` are invalid now. You don't need them anymore.
`s:` is still valid, but in practice, you never need it.
`v:` is no longer needed either in front of some common values: `true`,
`false`, `null`.
As for `g:`, how else would you tell Vim that the variable is global and
not local to the current script/function/block? Same thing for
buffer-local, window-local and tab-local variables. `b:`, `w:`, `t:` might
look weird, but we need a way to specify in which namespace such variable
names should be looked for. There is no equivalent in other programming
languages, because there is no concept of "current buffer", "current
window", "current tab page"... in them. Anyway, in practice, you rarely
need those scopes. The vast majority of your variables are script-local,
function-local, or block-local. And for all of those, no explicit scope is
required any longer.
On Sunday, July 4, 2021 at 11:52:29 PM UTC+2 stevelitt wrote:
> Bram Moolenaar said on Sun, 04 Jul 2021 23:30:01 +0200
>
>
> >Well, this works:
> >
> >def Fix_beginfigs()
> > g:index = 1
> > g/^beginfig(\d*);$/s//\='beginfig(' .. g:index .. ');'/ | g:index =
> > g:index + 1 unlet g:index
> >enddef
> >
> >However, using a legacy function would not be worse. The global
> >command does most of the work, what function it's in doesn't really
> >matter.
>
> Hi Bram,
>
> I try not to use global variables within functions. Is there an
> alternative enabling non-use of global variables?
>
> Also, I thought the new Vim9 Vimscript was getting rid of the need for
> g: and l: and a: etc. That stuff used to kill my brain.
>
> Thanks,
>
> SteveT
>
> Steve Litt
> Spring 2021 featured book: Troubleshooting Techniques of the Successful
> Technologist http://www.troubleshooters.com/techniques
>
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Re: Help converting function to Vim9 script
> Any idea what would be the best way to convert the snippet above?
Move the `i` variable in the script-local namespace. That is, don't
declare it inside the function, but at the script-level. You can still
reset it to a default value whenever the function is invoked:
vim9script
var i: number
def FixBeginfig()
i = 1
global /^beginfig(\d*);$/ substitute//\='beginfig(' .. i .. ');'/ |
++i
enddef
command -buffer -nargs=0 -bar FixBeginfigs FixBeginfig()
This works because – in a Vim9 script – all commands are executed in the
Vim9 script context. As a result, they have access to any Vim9 syntax, and
to all items defined in the script-local namespace.
Whether they're executed from a global command, an autocmd, a user command,
a simple `:execute`, ... it doesn't matter.
For this reason, in your user command definition, you don't need `:call`
nor ``. You don't need a bang after `:command` either since the patch
v8.1.0573.
---
However, as mentioned earlier, there won't be a speed increase because the
command is not compiled, just executed. Like most (all?) commands executed
by another command. This is confirmed by the output of `:disassemble`:
1_FixBeginfig
i = 1
0 PUSHNR 1
1 STORESCRIPT i-0 in /tmp/t.vim
global /^beginfig(\d*);$/ substitute//\='beginfig(' .. i .. ');'/ |
++i
2 EXEC global /^beginfig(\d*);$/ substitute//\='beginfig(' .. i
.. ');'/ | ++i
3 RETURN void
Notice that the second generated instruction is a simple `EXEC`.
FWIW, I would still refactor the code in Vim9. Mainly because of type
checking, and for better readability.
On Sunday, July 4, 2021 at 8:42:10 PM UTC+2 Lifepillar wrote:
> The MetaPost plugin in Vim contains the following definition to replace
> the n-th occurrence of `beginfig(...)` with `beginfig(n)`:
>
> function! s:fix_beginfigs()
> let i = 1
> g/^beginfig(\d*);$/s//\='beginfig('.i.');'/ | let i = i + 1
> endfunction
>
> command -nargs=0 FixBeginfigs call s:fix_beginfigs()
>
> On attempting to convert it to Vim9 script, I came up with this:
>
> def FixBeginfig()
> i = 1
> g/^beginfig(\d*);$/s//\='beginfig(' .. i .. ');'/ | i += 1
> enddef
>
> command! -buffer -nargs=0 -bar FixBeginfigs call FixBeginfig()
>
> But this results in 'Undefined variable: i', likely because the command
> is not evaluated in Vim9 script context.
>
> Any idea what would be the best way to convert the snippet above?
>
> Thanks,
> Life.
>
>
>
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Re: Help converting function to Vim9 script
> >Well, this works:
> >
> >def Fix_beginfigs()
> > g:index = 1
> > g/^beginfig(\d*);$/s//\='beginfig(' .. g:index .. ');'/ | g:index =
> > g:index + 1 unlet g:index
> >enddef
> >
> >However, using a legacy function would not be worse. The global
> >command does most of the work, what function it's in doesn't really
> >matter.
>
> Hi Bram,
>
> I try not to use global variables within functions. Is there an
> alternative enabling non-use of global variables?
>
> Also, I thought the new Vim9 Vimscript was getting rid of the need for
> g: and l: and a: etc. That stuff used to kill my brain.
Right, using global variables is not the best way. The thing is that
with a compiled function the local variables are on the stack, which
makes them unreachable for expressions that are not compiled.
Over time we have added these expressions in various places, which will
be evaluated in whatever context they are used. For a legacy function
the context is available, with dictionaries containing the local
variables. With compiled functions we have no such dictionaries, since
these add a lot of overhead.
The basic thing is, once you are in a compiled function, keep using
compiled expressions. When you escape to commands not using compiled
expressions, you run into trouble.
--
>From "know your smileys":
*<|:-) Santa Claus (Ho Ho Ho)
/// Bram Moolenaar -- b...@moolenaar.net -- http://www.Moolenaar.net \\\
/// \\\
\\\sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ ///
\\\help me help AIDS victims -- http://ICCF-Holland.org///
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Re: Help converting function to Vim9 script
Bram Moolenaar said on Sun, 04 Jul 2021 23:30:01 +0200
>Well, this works:
>
>def Fix_beginfigs()
> g:index = 1
> g/^beginfig(\d*);$/s//\='beginfig(' .. g:index .. ');'/ | g:index =
> g:index + 1 unlet g:index
>enddef
>
>However, using a legacy function would not be worse. The global
>command does most of the work, what function it's in doesn't really
>matter.
Hi Bram,
I try not to use global variables within functions. Is there an
alternative enabling non-use of global variables?
Also, I thought the new Vim9 Vimscript was getting rid of the need for
g: and l: and a: etc. That stuff used to kill my brain.
Thanks,
SteveT
Steve Litt
Spring 2021 featured book: Troubleshooting Techniques of the Successful
Technologist http://www.troubleshooters.com/techniques
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Re: Help converting function to Vim9 script
> The MetaPost plugin in Vim contains the following definition to replace
> the n-th occurrence of `beginfig(...)` with `beginfig(n)`:
>
> function! s:fix_beginfigs()
> let i = 1
> g/^beginfig(\d*);$/s//\='beginfig('.i.');'/ | let i = i + 1
> endfunction
>
> command -nargs=0 FixBeginfigs call s:fix_beginfigs()
>
> On attempting to convert it to Vim9 script, I came up with this:
>
> def FixBeginfig()
> i = 1
> g/^beginfig(\d*);$/s//\='beginfig(' .. i .. ');'/ | i += 1
> enddef
>
> command! -buffer -nargs=0 -bar FixBeginfigs call FixBeginfig()
>
> But this results in 'Undefined variable: i', likely because the command
> is not evaluated in Vim9 script context.
>
> Any idea what would be the best way to convert the snippet above?
Well, this works:
def Fix_beginfigs()
g:index = 1
g/^beginfig(\d*);$/s//\='beginfig(' .. g:index .. ');'/ | g:index = g:index +
1
unlet g:index
enddef
However, using a legacy function would not be worse. The global command
does most of the work, what function it's in doesn't really matter.
--
>From "know your smileys":
(:-# Said something he shouldn't have
/// Bram Moolenaar -- b...@moolenaar.net -- http://www.Moolenaar.net \\\
/// \\\
\\\sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ ///
\\\help me help AIDS victims -- http://ICCF-Holland.org///
--
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