On Tue, 21 Sep 2010, Bee wrote:
On Sep 21, 3:30 pm, "Israel Chauca F." wrote:
On Sep 21, 2010, at 5:02 PM, Bee wrote:
why use "let str = a:str" in a function
Looking at some functions, I have seen "let str = a:str"
a:vars are read-only, read :h a:var for more details.
Thank you, I missed the read-only part when reading about a:var
I missed that, too. Thanks.
The :help a:var does say "However, if a |List| or |Dictionary| is
used, you can change their contents."
I found this example function. Is {a:var} now a Dictionary?
function! Inc(var)
let {a:var} += 1
return {a:var}
endfunction
No. That's using 'Curly braces names':
:help curly-braces-names
In Perl, that's a "symbolic reference". PHP calls them "variable
variables" (oh, PHP).
Is one better than the other?
function! Inc(var)
let var = a:var
let var += 1
return var
endfunction
Your second example doesn't have the same effect. The one using the
"curly braces name" updates a variable, then returns its value. It's
using 'a:var' to hold the name of a variable. In your second example,
you're using the value of 'a:var' as a number.
:help internal-variables
See the effect of the curly-braces-name in the following example:
function! Inc(var)
let {a:var} += 1
return {a:var}
endfunction
let g:a = 1
echo "g:a =" g:a
echo "Inc(g:a) =" Inc('g:a')
echo "g:a =" g:a
" output:
" g:a = 1
" Inc(g:a) = 2
" g:a = 2
--
Best,
Ben
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