// Copyright 2017 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.lib.skylarkbuildapi;

import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;

/** Interface for provider objects (constructors for {@link StructApi} objects). */
@SkylarkModule(
  name = "Provider",
  doc =
      "A constructor for simple value objects, known as provider instances."
          + "<br>"
          + "This value has a dual purpose:"
          + "  <ul>"
          + "     <li>It is a function that can be called to construct 'struct'-like values:"
          + "<pre class=\"language-python\">DataInfo = provider()\n"
          + "d = DataInfo(x = 2, y = 3)\n"
          + "print(d.x + d.y) # prints 5</pre>"
          + "     Note: Some providers, defined internally, do not allow instance creation"
          + "     </li>"
          + "     <li>It is a <i>key</i> to access a provider instance on a"
          + "        <a href=\"Target.html\">Target</a>"
          + "<pre class=\"language-python\">DataInfo = provider()\n"
          + "def _rule_impl(ctx)\n"
          + "  ... ctx.attr.dep[DataInfo]</pre>"
          + "     </li>"
          + "  </ul>"
          + "Create a new <code>Provider</code> using the "
          + "<a href=\"globals.html#provider\">provider</a> function."
)
public interface ProviderApi extends SkylarkValue {}
