juliet_w schrieb:
> Hi guys,
>
> Here is a basic use of eval in vimscript that produces results that
> I don't understand.
>
>
> let kk = 1000
> echo 'tot is ' . eval(100+400+kk+200)
> " result is correct : tot is 1700
eval() is not needed here:
:echo 'tot is ' . (100+400+kk+200)
tot is 1700
but it works, because
eval(1700) == 1700
> let kk =1000
> let hi ='10+'
> echo 'tot is ' . eval( hi . 100+400+kk+200)
> " result is wrong : tot is 1610
>
> Why result is wrong in the second case?
> "hi' and kk values are added , but result should be 1710
Strings are converted to numbers before adding the results.
Numbers are converted to strings before concatenating the results.
"." and "+" have the same precedence.
:echo 1 + 2 . 3
:echo 3 . 3
33
:echo 2 . 3 + 1
:echo 23 + 1
24
:let kk = 1000
:let hi = '10+'
Missing parens added:
:echo 'tot is ' . (hi . (100+400+kk+200))
tot is 10+1700
:echo 'tot is ' . eval(hi . (100+400+kk+200))
tot is 1710
Step by step:
:echo 'tot is ' . eval(hi . (100+400+kk+200))
:echo 'tot is ' . eval(hi . 1700)
:echo 'tot is ' . eval(hi . '1700')
:echo 'tot is ' . eval('10+1700')
:echo 'tot is ' . 1710
:echo 'tot is ' . '1710'
:echo 'tot is 1710'
tot is 1710
Or (not recommended):
:let hi2 = '+10'
:echo 'tot is ' . eval(100+400+kk+200 . hi2)
tot is 1710
Also interesting (but does not influence the above result):
" wasn't there a thread about this (?):
:echo 0 + +10
10
:echo 0 + '+10'
0
! ^-- strange
:echo 0 + -10
-10
:echo 0 + '-10'
-10
--
Andy
--
You received this message from the "vim_use" maillist.
For more information, visit http://www.vim.org/maillist.php
