What are macros?

A marco is a sequence of vim actions that you can record for re-using.

Why use macros?

Consider the following case (this is extremely contrived but still): Let's say that you have a function like this.

def a_function(
    parameter_a: int,
    param_b: float,
    another_param_c: float,
) -> None:
  ...

Let's now say that you want to pack the arguments of a_function into a dictionary while keeping the names, like the following.

{
  "parameter_a": parameter_a,
  "param_b": param_b,
  "another_param_c": another_param_c,
}

You can achieve this manually, but you will (hopefully) notice that you are using the same keystroke for every line (every parameter). This is a good example of where macros can come in handy.

For each line, you can achieve the transformation by the following keystokes: 0vec""<ESC>Per=2bye$bvep.

Breakdown

• 0: Go to begining of line.
• vec: Visually select until end of this word and trigger change to enter input mode while copying the selected word.
• ""<ESC>P: Put two quotation marks, go to norma mode, and paste before the last quotation mark.
• er=: Go to end of word and replace with =.
• 2bye: Go back 2 words and copy the word (stuff inside quotation marks).
• $b: Go to the end of the line and back one word.
• vep: Select until the end of the word and paste to overwrite.

Using macros in vim

You can "record" macro by pressing q followed by a letter (a-z) and then the sequence of keystrokes you want to record. You can then replay the macro by pressing @ followed by the letter you used to record the macro.

For example, you can you can press qh to record a macro for h and execute your first line, then repeat them in the next line by pressing @h.

Using multi-line macros

Cool, but you still have to repeat the macro for each line. Surely there is a better way?

You can achieve multi-line macros by selecting the target lines and using the following command (press : to start a command).

'<,'>norm @h

Where norm is short for normal. And the '<,'> is a range that specifies the visual selection. If you used visual selection, this part should already be populated, so you just need to type norm @h and press enter.