luasnip snippets to create forms in markdown, useful for agents

markdown.lua

-- https://github.com/L3MON4D3/LuaSnip/blob/master/Examples/snippets.lua

-- extract functions from luasnips
local ls = require("luasnip")
local snippet = ls.snippet
local text_node = ls.text_node
local insert_node = ls.insert_node
local function_node = ls.function_node
local fmt = require("luasnip.extras.fmt").fmt

--------------------------------------------------------------------------------
-- helpers
--------------------------------------------------------------------------------

local PANEL_WIDTH = 72

local function dw(s)
  return vim.fn.strdisplaywidth(s or "")
end

local function pad_right(s, width)
  return s .. string.rep(" ", math.max(0, width - dw(s)))
end

--- Cola del borde superior: rellena con ─ hasta PANEL_WIDTH según el título.
local function top_border_tail(args)
  local title_width = dw(args[1][1])
  return " " .. string.rep("─", math.max(1, PANEL_WIDTH - 5 - title_width)) .. "┐"
end

return {
  --------------------------------------------------------------------------------
  --- Forms
  --------------------------------------------------------------------------------
  -- Panel de una sola línea, editable en vivo (el borde se reajusta al escribir).
  snippet("panel_line", {
    text_node("┌─ "),
    insert_node(1, "Título"),
    function_node(top_border_tail, { 1 }),
    text_node({ "", "│ " }),
    insert_node(2, "contenido"),
    function_node(function(args)
      return pad_right("", PANEL_WIDTH - 4 - dw(args[1][1])) .. " │"
    end, { 2 }),
    text_node({ "", "└" .. string.rep("─", PANEL_WIDTH - 2) .. "┘" }),
  }, {
    desc = "Panel con título de una sola línea de contenido",
  }),

  -- Panel vacío de N líneas para rellenar a mano.
  snippet("panel_blank", {
    text_node("┌─ "),
    insert_node(1, "Título"),
    function_node(top_border_tail, { 1 }),
    text_node({
      "",
      "│ " .. string.rep(" ", PANEL_WIDTH - 4) .. " │",
      "│ " .. string.rep(" ", PANEL_WIDTH - 4) .. " │",
      "│ " .. string.rep(" ", PANEL_WIDTH - 4) .. " │",
      "└" .. string.rep("─", PANEL_WIDTH - 2) .. "┘",
    }),
  }, {
    desc = "Panel vacío con título",
  }),

  -- Leyenda de notación: ponla una vez arriba del wireframe.
  snippet("form_legend", {
    text_node({
      "Notación:",
      "  [ ] / [x] checkbox        ( ) / (•) radio        (●—) toggle activo",
      "  [__________] texto        [ 0 ] número (rango)   [ 2026-01-29 📅 ] fecha",
      "  [ Opción ▾ ] select       ┌─┐ textarea           [ 📎 Adjuntar… ] archivo",
      "  【 Primario 】 ( Secundario )    « solo lectura / calculado »    🔒 deshabilitado",
      "  * requerido    ↳ ayuda o validación    ⟳ fila repetible",
      "",
    }),
  }, {
    desc = "Leyenda de la notación de controles",
  }),

  -- Andamio completo de pantalla.
  snippet(
    "form_screen",
    fmt(
      [================================================[
## <1>

<2>*  [__________]
<3>   [ <4> ▾ ]
      ↳ opciones: <5>

【 Guardar 】   ( Cancelar )
]================================================],
      {
        insert_node(1, "TÍTULO DE LA PANTALLA"),
        insert_node(2, "Campo"),
        insert_node(3, "Otro campo"),
        insert_node(4, "Opción por defecto"),
        insert_node(5, "A / B / C"),
      },
      { delimiters = "<>" }
    ),
    { desc = "Andamio de pantalla de formulario" }
  ),

  -- Controles sueltos
  snippet("form_text", fmt("<1>*  [__________]", { insert_node(1, "Etiqueta") }, { delimiters = "<>" }), { desc = "Input de texto" }),

  snippet("form_number", fmt("<1>*  [ <2> ] (<3>)", { insert_node(1, "Etiqueta"), insert_node(2, "0"), insert_node(3, "0–100, entero") }, { delimiters = "<>" }), { desc = "Input numérico con rango" }),

  snippet(
    "form_checkbox",
    fmt(
      [================================================[
<1>
  [x] <2>
  [ ] <3>
  [ ] <4>
  ↳ <5>
]================================================],
      {
        insert_node(1, "Etiqueta del grupo"),
        insert_node(2, "Opción A"),
        insert_node(3, "Opción B"),
        insert_node(4, "Opción C"),
        insert_node(5, "al menos una"),
      },
      { delimiters = "<>" }
    ),
    { desc = "Grupo de checkboxes" }
  ),

  snippet(
    "form_radio",
    fmt("<1>*  (•) <2>   ( ) <3>   ( ) <4>", {
      insert_node(1, "Etiqueta"),
      insert_node(2, "Opción A"),
      insert_node(3, "Opción B"),
      insert_node(4, "Opción C"),
    }, { delimiters = "<>" }),
    { desc = "Grupo de radios en línea" }
  ),

  snippet(
    "form_select",
    fmt(
      [================================================[
<1>*  [ <2> ▾ ]
      ↳ opciones: <3>
]================================================],
      {
        insert_node(1, "Etiqueta"),
        insert_node(2, "Valor por defecto"),
        insert_node(3, "A / B / C"),
      },
      { delimiters = "<>" }
    ),
    { desc = "Select con lista de opciones" }
  ),

  snippet(
    "form_textarea",
    fmt(
      [================================================[
<1>
┌──────────────────────────────────────────────────┐
│                                                  │
│                                                  │
└──────────────────────────────────────────────────┘
  ↳ <2>
]================================================],
      { insert_node(1, "Etiqueta"), insert_node(2, "máx. 500 caracteres") },
      { delimiters = "<>" }
    ),
    { desc = "Textarea" }
  ),

  snippet(
    "form_toggle",
    fmt("<1>  (●—) <2>   /   (—●) <3>", {
      insert_node(1, "Etiqueta"),
      insert_node(2, "activo"),
      insert_node(3, "inactivo"),
    }, { delimiters = "<>" }),
    { desc = "Toggle" }
  ),

  snippet(
    "form_date",
    fmt("<1>*  [ <2> 📅 ]", {
      insert_node(1, "Fecha"),
      function_node(function()
        return os.date("%Y-%m-%d")
      end),
    }, { delimiters = "<>" }),
    { desc = "Input de fecha" }
  ),

  snippet(
    "form_file",
    fmt("<1>  [ 📎 <2> ]  ↳ <3>", {
      insert_node(1, "Adjuntos"),
      insert_node(2, "Seleccionar archivo…"),
      insert_node(3, "pdf, jpg — máx. 5 MB"),
    }, { delimiters = "<>" }),
    { desc = "Input de archivo" }
  ),

  snippet("form_readonly", fmt("<1>  « <2> »", { insert_node(1, "Etiqueta"), insert_node(2, "valor calculado") }, { delimiters = "<>" }), { desc = "Campo de solo lectura / calculado" }),

  snippet("form_actions", fmt("【 <1> 】   ( <2> )", { insert_node(1, "Guardar"), insert_node(2, "Cancelar") }, { delimiters = "<>" }), { desc = "Botones primario y secundario" }),

  snippet("form_rule", fmt("↳ <1>", { insert_node(1, "regla de validación") }, { delimiters = "<>" }), { desc = "Línea de ayuda / validación" }),

  -- Tabla de filas repetibles.
  snippet(
    "form_table",
    fmt(
      [================================================[
⟳ una fila por <1>

| <2>   | <3>      | <4>   |
| ----- | -------- | ----- |
| valor | [ 0 ]    | [ ▾ ] |
| valor | [ 0 ]    | [ ▾ ] |
]================================================],
      {
        insert_node(1, "partida"),
        insert_node(2, "Columna A"),
        insert_node(3, "Columna B"),
        insert_node(4, "Columna C"),
      },
      { delimiters = "<>" }
    ),
    { desc = "Tabla markdown de filas repetibles" }
  ),
}