Erlang Macro Processor (v2)

Put on GitHub by Andreas Stenius.

This is the emp2 written by Philip Robinson. See his blog for full details: http://chlorophil.blogspot.com/2007/04/erlang-macro-processor-v2-part-v.html

Example usage

The macro definition (in it's own module):

-module(example_macro).
-export([lookup_binary/1]).

lookup_binary(Size) ->
    [[$,,FirstVal]|NumberString] = lists:map(
        fun(Offset) -> io_lib:format(",~B", [Offset * 2]) end,
        lists:seq(0, Size - 1)),
    "<<" ++ [FirstVal] ++ NumberString ++ ">>".

Then you may use it from other modules:

-module(example).
-export([lookup/1]).

-compile({parse_transform, emp2}).
-macro_modules([example_macro]).

lookup(Offset) ->
    <<_:Offset/binary,Value:8/integer,_/binary>> =
        example_macro:lookup_binary(4),
    Value.

Example output:

1> [example:lookup(N) || N <- lists:seq(0, 3)].
[0,2,4,6]
2>

Erlang Macro Processor (v1)

Is also supported (see http://chlorophil.blogspot.com/2007/04/erlang-macro-processor-v1-part-i.html).