feat(API): simplify preview as lua function

lua/fzf-lua/core.lua

@@ -566,6 +566,30 @@ M.build_fzf_cli = function(opts)
       opts.fzf_opts["--" .. flag] = opts[flag]
     end
   end
+  -- convert preview action functions to strings using our shell wrapper
+  do
+    local preview_cmd
+    local preview_spec = opts.fzf_opts["--preview"]
+    if type(preview_spec) == "function" then
+      preview_cmd = shell.raw_action(preview_spec, "{}", opts.debug)
+    elseif type(preview_spec) == "table" then
+      preview_spec = vim.tbl_extend("keep", preview_spec, {
+        fn = preview_spec.fn or preview_spec[1],
+        -- by default we use current item only "{}"
+        -- using "{+}" will send multiple selected items
+        field_index = "{}",
+      })
+      if preview_spec.type == "cmd" then
+        preview_cmd = shell.raw_preview_action_cmd(
+          preview_spec.fn, preview_spec.field_index, opts.debug)
+      else
+        preview_cmd = shell.raw_action(preview_spec.fn, preview_spec.field_index, opts.debug)
+      end
+    end
+    if preview_cmd then
+      opts.fzf_opts["--preview"] = preview_cmd
+    end
+  end
   opts.fzf_opts["--bind"] = M.create_fzf_binds(opts.keymap.fzf)
   opts.fzf_opts["--color"] = M.create_fzf_colors(opts)
   opts.fzf_opts["--expect"] = actions.expect(opts.actions)

lua/fzf-lua/providers/module.lua

@@ -2,7 +2,6 @@ local uv = vim.uv or vim.loop
 local core = require "fzf-lua.core"
 local path = require "fzf-lua.path"
 local utils = require "fzf-lua.utils"
-local shell = require "fzf-lua.shell"
 local config = require "fzf-lua.config"
 
 local M = {}
@@ -21,11 +20,10 @@ M.metatable = function(opts)
 
   table.sort(methods, function(a, b) return a < b end)
 
-  opts.preview = shell.raw_action(function(args)
-    -- TODO: retrieve method help
-    local help = ""
-    return string.format("%s:%s", args[1], help)
-  end, nil, opts.debug)
+  opts.preview = function(args)
+    local options_md = require("fzf-lua.cmd").options_md()
+    return type(options_md) == "table" and options_md[args[1]:lower()] or ""
+  end
 
   opts.fzf_opts["--preview-window"] = "hidden:down:10"
 

lua/fzf-lua/providers/nvim.lua

@@ -2,7 +2,6 @@ local uv = vim.uv or vim.loop
 local core = require "fzf-lua.core"
 local path = require "fzf-lua.path"
 local utils = require "fzf-lua.utils"
-local shell = require "fzf-lua.shell"
 local config = require "fzf-lua.config"
 local devicons = require "fzf-lua.devicons"
 
@@ -51,13 +50,13 @@ M.commands = function(opts)
     table.sort(entries, function(a, b) return a < b end)
   end
 
-  opts.preview = shell.raw_action(function(args)
+  opts.preview = function(args)
     local cmd = args[1]
     if commands[cmd] then
       cmd = vim.inspect(commands[cmd])
     end
     return cmd
-  end, nil, opts.debug)
+  end
 
   core.fzf_exec(entries, opts)
 end
@@ -216,7 +215,7 @@ M.marks = function(opts)
     string.format("%-5s %s  %s %s", "mark", "line", "col", "file/text"))
 
   opts.fzf_opts["--header-lines"] = 1
-  --[[ opts.preview = shell.raw_action(function (args, fzf_lines, _)
+  --[[ opts.preview = function (args, fzf_lines, _)
     local mark = args[1]:match("[^ ]+")
     local bufnr, lnum, _, _ = unpack(vim.fn.getpos("'"..mark))
     if vim.api.nvim_buf_is_loaded(bufnr) then
@@ -228,7 +227,7 @@ M.marks = function(opts)
       end
       return "UNLOADED: " .. name
     end
-  end) ]]
+  end ]]
 
   core.fzf_exec(entries, opts)
 end
@@ -274,11 +273,11 @@ M.registers = function(opts)
     end
   end
 
-  opts.preview = shell.raw_action(function(args)
+  opts.preview = function(args)
     local r = args[1]:match("%[(.*)%] ")
     local _, contents = pcall(vim.fn.getreg, r)
     return contents and register_escape_special(contents) or args[1]
-  end, nil, opts.debug)
+  end
 
   core.fzf_exec(entries, opts)
 end

lua/fzf-lua/shell.lua

@@ -69,8 +69,7 @@ function M.raw_async_action(fn, fzf_field_expression, debug)
     end)
     uv.pipe_connect(pipe, pipe_path, function(err)
       if err then
-        error(string.format("pipe_connect(%s) failed with error: %s",
-          pipe_path, err))
+        error(string.format("pipe_connect(%s) failed with error: %s", pipe_path, err))
       else
         vim.schedule(function()
           fn(pipe, unpack(args))
@@ -110,11 +109,6 @@ function M.raw_async_action(fn, fzf_field_expression, debug)
   return action_cmd, id
 end
 
-function M.async_action(fn, fzf_field_expression, debug)
-  local action_string, id = M.raw_async_action(fn, fzf_field_expression, debug)
-  return libuv.shellescape(action_string), id
-end
-
 function M.raw_action(fn, fzf_field_expression, debug)
   local receiving_function = function(pipe, ...)
     local ret = fn(...)