I am trying to extend the Erlang Mixer Library (https://github.com/opscode/mixer) to pass the "-spec()." lines for the functions that it is adding to a module. However I am unclear on how erlc places specs into the core erlang code.
I started with a really simple (test) module:
-module(mix1).
-export([square/1]).
-spec(square(number()) -> number()).
square(X) -> X * X.
And compiled it with "erlc +debug_info -S mix1.erl" and got this (module_info functions removed):
{module, mix1}. %% version = 0
{exports, [{module_info,0},{module_info,1},{square,1}]}.
{attributes, []}.
{labels, 7}.
{function, square, 1, 2}.
{label,1}.
{line,[{location,"mix1.erl",7}]}.
{func_info,{atom,mix1},{atom,square},1}.
{label,2}.
{line,[{location,"mix1.erl",8}]}.
{gc_bif,'*',{f,0},1,[{x,0},{x,0}],{x,0}}.
return.
I am trying to figure out how the "-spec()" are translated and I don't see them there, any ideas? What am I missing. The eventual goal here is to use this for a parse transform.
I believe your output is not exactly AST, but some normalized form of AST.
{ok, Forms} = epp:parse_file("mix1.erl",[],[]).
{ok,[{attribute,1,file,{"mix1.erl",1}},
{attribute,1,module,mix1},
{attribute,2,export,[{square,1}]},
{attribute,3,spec,
{{square,1},
[{type,3,'fun',
[{type,3,product,[{type,3,number,[]}]},
{type,3,number,[]}]}]}},
{function,4,square,1,
[{clause,4,
[{var,4,'X'}],
[],
[{op,4,'*',{var,4,'X'},{var,4,'X'}}]}]},
{eof,6}]}