-- jumpable mappings
vim.keymap.set("i", "<Tab>", "vsnip#jumpable(1)  ? '<Plug>(vsnip-jump-next)' : '<Tab>'", { expr = true })
vim.keymap.set("s", "<Tab>", "vsnip#jumpable(1)  ? '<Plug>(vsnip-jump-next)' : '<Tab>'", { expr = true })
vim.keymap.set("i", "<S-Tab>", "vsnip#jumpable(-1) ? '<Plug>(vsnip-jump-prev)' : '<S-Tab>'", { expr = true })
vim.keymap.set("s", "<S-Tab>", "vsnip#jumpable(-1) ? '<Plug>(vsnip-jump-prev)' : '<S-Tab>'", { expr = true })