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[;1m-spec erlang:fun_to_list(Fun) -> String :: string()[0m
[;1m when Fun :: function().[0m
Returns [;;4mString[0m that represents the code that created [;;4mFun[0m.
[;;4mString[0m has the following form, if [;;4mFun[0m was created by a fun
expression of the form [;;4mfun ModuleName:FuncName/Arity[0m:
[;;4m"fun ModuleName:FuncName/Arity"[0m
The form of [;;4mString[0m when [;;4mFun[0m is created from other types of
fun expressions differs depending on if the fun expression was
executed while executing compiled code or if the fun expression
was executed while executing uncompiled code (uncompiled escripts,
the Erlang shell, and other code executed by the erl_eval module):
[;;4mcompiled code[0m:
[;;4m"#Fun<M.I.U>"[0m, where M, I and U correspond to the values
named [;;4mmodule[0m, [;;4mindex[0m and [;;4muniq[0m in the result of [;;4m[0m
[;;4merlang:fun_info(Fun)[0m.
[;;4muncompiled code[0m:
All funs created from fun expressions in uncompiled code with
the same arity are mapped to the same list by [;;4mfun_to_list/1[0m.
Note:
Generally, one can not use [;;4mfun_to_list/1[0m to check if two
funs are equal as [;;4mfun_to_list/1[0m does not take the fun's
environment into account. See [;;4merlang:fun_info/1[0m for how to
get the environment of a fun.
Note:
The output of [;;4mfun_to_list/1[0m can differ between Erlang
implementations and may change in future versions.
Examples:
-module(test).
-export([add/1, add2/0, fun_tuple/0]).
add(A) -> fun(B) -> A + B end.
add2() -> fun add/1.
fun_tuple() -> {fun() -> 1 end, fun() -> 1 end}.
> {fun test:add/1, test:add2()}.
{fun test:add/1,#Fun<test.1.107738983>}
Explanation: [;;4mfun test:add/1[0m is upgradable but [;;4mtest:add2()[0m is
not upgradable.
> {test:add(1), test:add(42)}.
{#Fun<test.0.107738983>,#Fun<test.0.107738983>}
Explanation: [;;4mtest:add(1)[0m and [;;4mtest:add(42)[0m has the same string
representation as the environment is not taken into account.
>test:fun_tuple().
{#Fun<test.2.107738983>,#Fun<test.3.107738983>}
Explanation: The string representations differ because the funs
come from different fun expressions.
> {fun() -> 1 end, fun() -> 1 end}. >
{#Fun<erl_eval.45.97283095>,#Fun<erl_eval.45.97283095>}
Explanation: All funs created from fun expressions of this form in
uncompiled code with the same arity are mapped to the same list by [;;4m[0m
[;;4mfun_to_list/1[0m.
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