vim计算表达式

2+3=

normal模式下，在当前行输入；bc

2+3=5

Chaining is now allowed: 

start with this 

2 + 3 = 
;bc 
2 + 3 = 5 
add some more stuff: 
2 + 3 = 5 * 2 = 
;bc 
2  + 3 = 5 * 2 = 10

http://vim.sourceforge.net/scripts/script.php?script_id=219