Vim Expression Register - Calculator in Vim

• Temporary register that can be used to run snippets of Vim script
  • Can be used to evaluate Vim scripts without leaving the current editor context
  • Can also perform mathematical calculations

How to enter "expression register" mode?

<ctrl-r>= from insert mode

• Result of the expression is printed at the cursor position

Example

Typing 2 + 3 in the expression register and pressing <Enter> will print the output (5) at the cursor position

How to evaluate an expression already present in the file?

1. In visual mode, select the expression
2. yank the expression into Vim’s default register, using y
3. Enter into expression register
4. <ctrl-r>" will help you paste the yanked expression into the register
5. <enter> will perform the calculation and print the result at the cursor position

Sources

• https://vimtricks.com/p/vim-calculator/