Pasting a copied parameter before/after the current parameter

I think it would be so useful to use something like this:

require'nvim-treesitter.configs'.setup {
  textobjects = {
    select = {
     enable = true,
      keymaps = {
        ["ap"] = "@parameter.outer", 
      }
    }    
  }
}

nmap <leader>P :TSPasteParameterBefore<CR>
nmap <leader>p :TSPasteParameterAfter<CR>

Then if I could take a function call like:

blah(arg1, arg2, arg3);

and hover arg2 and use dap to delete arg2.

Then hover arg1 and use a keybinding to paste the parameter I just copied before arg1 or use a different keybinding to paste the parameter after arg1 (in this case <leader>P for "before" and <leader>p for "after").

When I do dap it copies the preceding , (or sometimes the trailing ,). When pasting the code would first need to remove the preceding/trailing , and then enter a new , after the pasted parameter when pasting before the final parameter, or enter a preceding , when pasting into the final parameter position. If there are no parameters then no trailing/preceding , would be added (for languages that support trailing , after the last parameter, could leave it up to the user's code formatter to handle this but in cases where a trailing , already exists then pasting into the final parameter position should not enter the preceding ,). I'm aware there are languages that don't use , between parameters such as Haskell, for such languages it would be easier.

This might not be the direction you see nvim-treesitter-textobjects going, and if not, I'm happy to provide this support in a new plugin, but I'd be really grateful for any advice you could give me on how I might implement this.

Start by reviewing the nvim-treesitter-textobjects setup shown in the issue, especially the @parameter.outer selection and proposed TSPasteParameterBefore/TSPasteParameterAfter mappings. Trace how dap deletes or copies a parameter, then determine how parameter separators should behave across the listed cases and languages. Done means copied parameters can be pasted before or after the active parameter without malformed separators.