How do I programmatically set a register with a specific type (characterwise, linewise, blockwise)?

Explanation

The setreg() function sets a register's content AND its type in one call. Register type matters when pasting — linewise content pastes on its own line, characterwise pastes inline, and blockwise pastes as a rectangular block. Without setting the type correctly, a paste may behave unexpectedly.

Register types

Syntax

call setreg('{register}', {value}, '{type}')

Examples

Set register a to a linewise value:

:call setreg('a', 'line of text', 'l')
:put a    " pastes on its own line

Set register a to characterwise:

:call setreg('a', 'inline text', 'c')
:normal "ap    " pastes inline

Convert a register from characterwise to linewise:

:call setreg('a', @a, 'l')

Now "ap pastes @a on its own line, even if it was originally copied inline.

Set the clipboard register with a linewise value:

:call setreg('+', join(['line1', 'line2'], "\n"), 'l')

Tips

• getreg('a') retrieves the content; getregtype('a') retrieves the type ('v', 'V', or "\x16" for block)
• Type conversion is the main use case: if "ap pastes at the wrong level, fix it with setreg()
• setreg('/', @a) sets the search register — same as :let @/ = @a but can set type
• :let @a = 'text' always creates a characterwise register; setreg() is the only way to set other types