edocstrings

A docstring is a string literal that occurs as the first expression in a function.

-module(math2).

-export([math/2]).

sum(A, B) ->
    "Returns the sum of the two provided numbers.",
    A + B.

Docstrings can be accessed by invoking the <MODULE>:help(<FUNCTION>, <ARITY>) function.

In the example above, sum/2's docstring can be accessed by calling math2:help(sum, 2), which returns the "Returns the sum of the two provided numbers." string literal.

math2:help(sum, 2).
"Returns the sum of the two provided numbers."

Considerations

• In functions with more than one clause, the docstring must be defined as the first expression in the first clause.

• Docstrings can only be defined for exported functions.

• edocstrings will inject a help/2 function to all your modules compiled using the edocstirngs_ptransform parse transform.

Usage

If you want to use docstrings in your Erlang project, all you need to do is add edocstring as a dependency and make sure you compile your erlang modules using the edocstrings's parse transform.

You can enable the edocstring_ptransform parse transform on an individual Erlang module by using the -compile(<COMPILE_OPTION>) module attribute.

-module(math2).

-compile({parse_transform, edocstring_ptransform}).

-export([math/2]).

sum(A, B) ->
    "Returns the sum of the two provided numbers.",
    A + B.

Alternatively, you can tell the Erlang compiler that you want to use the edocstrings's parse transform by using the +{parse_transform,edocstrings_ptransform} compile option when invoking the Erlang compiler.

Author(s)

• Enrique Fernandez <enrique.fernandez@erlang-solutions.com>

License

The MIT License (MIT)

Copyright (c) 2015 Enrique Fernández

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.