feat: Allow overriding actions from mappings (#248)

lua/telescope/actions/mt.lua

@@ -0,0 +1,96 @@
+
+local action_mt = {}   
+
+action_mt.create = function(mod)
+  local mt = {
+    __call = function(t, ...)
+      local values = {}
+      for _, v in ipairs(t) do
+        local func = t._replacements[v] or mod[v]
+
+        if t._pre[v] then
+          t._pre[v](...)
+        end
+
+        local result = {func(...)}
+        for _, res in ipairs(result) do
+          table.insert(values, res)
+        end
+
+        if t._post[v] then
+          t._post[v](...)
+        end
+      end
+
+      return unpack(values)
+    end,
+
+    __add = function(lhs, rhs)
+      local new_actions = {}
+      for _, v in ipairs(lhs) do
+        table.insert(new_actions, v)
+      end
+
+      for _, v in ipairs(rhs) do
+        table.insert(new_actions, v)
+      end
+
+      return setmetatable(new_actions, getmetatable(lhs))
+    end,
+
+    _pre = {},
+    _replacements = {},
+    _post = {},
+  }
+
+  mt.__index = mt
+
+  mt.clear = function()
+    mt._pre = {}
+    mt._replacements = {}
+    mt._post = {}
+  end
+
+  --- Replace the reference to the function with a new one temporarily
+  function mt:replace(v)
+    assert(#self == 1, "Cannot replace an already combined action")
+
+    local action_name = self[1]
+    mt._replacements[action_name] = v
+  end
+
+  function mt:enhance(opts)
+    assert(#self == 1, "Cannot enhance already combined actions")
+
+    local action_name = self[1]
+    if opts.pre then
+      mt._pre[action_name] = opts.pre
+    end
+
+    if opts.post then
+      mt._post[action_name] = opts.post
+    end
+  end
+
+  return mt
+end
+
+action_mt.transform = function(k, mt)
+  return setmetatable({k}, mt)
+end
+
+action_mt.transform_mod = function(mod)
+  local mt = action_mt.create(mod)
+
+  local redirect = {}
+
+  for k, _ in pairs(mod) do
+    redirect[k] = action_mt.transform(k, mt)
+  end
+
+  redirect._clear = mt.clear
+
+  return redirect
+end
+
+return action_mt