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-rw-r--r--lib/compiler/test/map_SUITE.erl387
1 files changed, 382 insertions, 5 deletions
diff --git a/lib/compiler/test/map_SUITE.erl b/lib/compiler/test/map_SUITE.erl
index 403b7e8405..cfa8262701 100644
--- a/lib/compiler/test/map_SUITE.erl
+++ b/lib/compiler/test/map_SUITE.erl
@@ -21,6 +21,7 @@
]).
-export([
+ %% literals
t_build_and_match_literals/1,
t_update_literals/1,t_match_and_update_literals/1,
t_update_map_expressions/1,
@@ -32,6 +33,15 @@
t_map_size/1,
t_build_and_match_aliasing/1,
+ %% variables
+ t_build_and_match_variables/1,
+ t_update_assoc_variables/1,t_update_exact_variables/1,
+ t_nested_pattern_expressions/1,
+ t_guard_update_variables/1,
+ t_guard_sequence_variables/1,
+ t_guard_sequence_mixed/1,
+ t_frequency_table/1,
+
%% warnings
t_warn_useless_build/1,
t_warn_pair_key_overloaded/1,
@@ -51,7 +61,10 @@
suite() -> [].
-all() -> [
+all() ->
+ test_lib:recompile(?MODULE),
+ [
+ %% literals
t_build_and_match_literals,
t_update_literals, t_match_and_update_literals,
t_update_map_expressions,
@@ -62,6 +75,15 @@ all() -> [
t_map_size,
t_build_and_match_aliasing,
+ %% variables
+ t_build_and_match_variables,
+ t_update_assoc_variables,t_update_exact_variables,
+ t_nested_pattern_expressions,
+ t_guard_update_variables,
+ t_guard_sequence_variables,
+ t_guard_sequence_mixed,
+ t_frequency_table,
+
%% warnings
t_warn_useless_build,
t_warn_pair_key_overloaded,
@@ -73,6 +95,7 @@ all() -> [
t_build_and_match_nil,
t_build_and_match_structure,
+
%% errors in 17.0-rc1
t_update_values,
t_expand_map_update,
@@ -119,6 +142,11 @@ t_build_and_match_literals(Config) when is_list(Config) ->
%% nil key
#{[]:=ok,1:=2} = id(#{[]=>ok,1=>2}),
+ #{1:=2,[]:=ok,1:=2} = id(#{[]=>ok,1=>2}),
+
+ %% pseudo literals
+ #{ -3 := yep } = id(#{ -3 => yep }),
+ #{ <<0:358>> := "three" } = id(#{<<0:358>> =>"three"}),
%% error case
{'EXIT',{{badmatch,_},_}} = (catch (#{x:=3,x:=2} = id(#{x=>3}))),
@@ -126,10 +154,10 @@ t_build_and_match_literals(Config) when is_list(Config) ->
{'EXIT',{{badmatch,_},_}} = (catch (#{x:=3} = id({a,b,c}))),
{'EXIT',{{badmatch,_},_}} = (catch (#{x:=3} = id(#{y=>3}))),
{'EXIT',{{badmatch,_},_}} = (catch (#{x:=3} = id(#{x=>"three"}))),
- {'EXIT',{badarg,_}} = (catch id(#{<<0:258>> =>"three"})),
{'EXIT',{{badmatch,_},_}} = (catch (#{#{"a"=>42} := 3}=id(#{#{"a"=>3}=>42}))),
ok.
+
t_build_and_match_aliasing(Config) when is_list(Config) ->
M1 = id(#{a=>1,b=>2,c=>3,d=>4}),
#{c:=C1=_=_=C2} = M1,
@@ -143,6 +171,19 @@ t_build_and_match_aliasing(Config) when is_list(Config) ->
M2 = id(#{"a"=>1,"b"=>2,"c"=>3,"d"=>4}),
#{"a":=A2,"a":=A2,"a":=A2,"b":=B2,"b":=B2,"b":=2} = M2,
#{"a":=_,"a":=_,"a":=_,"b":=_,"b":=_,"b":=2} = M2,
+
+ #{a:=A1,a:=A1,a:=A1,b:=B1,b:=B1} = #{a:=A1,a:=A1,a:=A1,b:=B1,b:=B1,b:=2} = M1,
+ #{"a":=A3,"b":=B3} = #{"a":=A3,"a":=A3} = #{"b":=B3,"b":=2} = M2,
+
+ #{"a":=1,"b":=2,"c":=3,"d":=4} = #{"a":=A4,"b":=B4} = #{"a":=A4,"a":=A4} = #{"b":=B4,"d":=4} = M2,
+ #{"a":=A5,"b":=B5} = #{"a":=A5,"a":=A5} = #{"b":=B5,"d":=4} = #{"a":=1,"b":=2,"c":=3,"d":=4} = M2,
+ #{"a":=_,"b":=_} = #{"a":=_,"a":=_} = #{"b":=_,"d":=4} = #{"a":=1,"b":=2,"c":=3,"d":=4} = M2,
+
+ M3 = id(#{<<12:300>>=>1,<<13:300>>=>2}),
+ #{<<12:300>> := V1, <<13:300>> := V2} = #{<<13:300>> := V2, <<12:300>> := V1} = M3,
+ #{<<12:300>> := 1, <<13:300>> := 2} = #{<<13:300>> := _, <<12:300>> := _} = M3,
+ #{<<13:300>> := _, <<12:300>> := _} = #{<<12:300>> := 1, <<13:300>> := 2} = M3,
+
ok.
t_map_size(Config) when is_list(Config) ->
@@ -241,11 +282,14 @@ t_update_assoc(Config) when is_list(Config) ->
#{1:=a,2:=b,3.0:=new,4:=d,5:=e} = M2,
M2 = M0#{3.0:=wrong,3.0=>new},
+ % Can't handle directly yet
+ Bin = <<0:257>>,
+ #{ Bin := val } = id(M0#{<<0:257>> => val}), %% binary limitation
+
%% Errors cases.
BadMap = id(badmap),
{'EXIT',{badarg,_}} = (catch BadMap#{nonexisting=>val}),
{'EXIT',{badarg,_}} = (catch <<>>#{nonexisting=>val}),
- {'EXIT',{badarg,_}} = (catch M0#{<<0:257>> => val}), %% limitation
ok.
t_update_exact(Config) when is_list(Config) ->
@@ -275,14 +319,22 @@ t_update_exact(Config) when is_list(Config) ->
{'EXIT',{badarg,_}} = (catch M0#{42=>v1,42.0:=v2,42:=v3}),
{'EXIT',{badarg,_}} = (catch <<>>#{nonexisting:=val}),
{'EXIT',{badarg,_}} = (catch M0#{<<0:257>> := val}), %% limitation
+
+ %% A workaround for a bug allowed an empty map to be updated.
+ {'EXIT',{badarg,_}} = (catch (id(#{}))#{a:=1}),
+ {'EXIT',{badarg,_}} = (catch #{}#{a:=1}),
+ Empty = #{},
+ {'EXIT',{badarg,_}} = (catch Empty#{a:=1}),
ok.
t_update_values(Config) when is_list(Config) ->
V0 = id(1337),
M0 = #{ a => 1, val => V0},
V1 = get_val(M0),
- M1 = M0#{ val := [V0,V1], "wazzup" => 42 },
+ M1 = id(M0#{ val := [V0,V1], "wazzup" => 42 }),
[1337, {some_val, 1337}] = get_val(M1),
+ M2 = id(M1#{ <<42:333>> => 1337 }),
+ {bin_key,1337} = get_val(M2),
N = 110,
List = [{[I,1,2,3,I],{1,2,3,"wat",I}}|| I <- lists:seq(1,N)],
@@ -308,6 +360,7 @@ t_export(Config) when is_list(Config) ->
check_val(#{val1:=V1, val2:=V2},V1,V2) -> ok.
+get_val(#{ <<42:333>> := V }) -> {bin_key, V};
get_val(#{ "wazzup" := _, val := V}) -> V;
get_val(#{ val := V }) -> {some_val, V}.
@@ -437,7 +490,10 @@ guard_receive_loop() ->
t_list_comprehension(Config) when is_list(Config) ->
- [#{k:=1},#{k:=2},#{k:=3}] = [#{k=>I} || I <- [1,2,3]],
+ [#{k:=1},#{k:=2},#{k:=3}] = id([#{k=>I} || I <- [1,2,3]]),
+ Ls = id([#{<<2:301>> => I, "wat" => I + 1} || I <- [1,2,3]]),
+ [#{<<2:301>>:=1,"wat":=2},#{<<2:301>>:=2,"wat":=3},#{<<2:301>>:=3,"wat":=4}] = Ls,
+ [{1,2},{2,3},{3,4}] = id([{I2,I1} || #{"wat" := I1, <<2:301>> := I2} <- Ls]),
ok.
t_guard_fun(Config) when is_list(Config) ->
@@ -585,6 +641,7 @@ t_build_and_match_nil(Config) when is_list(Config) ->
"treat" => V2,
[] => V1 }),
#{ [] := V3, [] := V3 } = id(#{ [] => V1, [] => V3 }),
+ #{ <<1>> := V3, [] := V1 } = id(#{ [] => V1, <<1>> => V3 }),
ok.
t_build_and_match_structure(Config) when is_list(Config) ->
@@ -601,5 +658,325 @@ t_build_and_match_structure(Config) when is_list(Config) ->
end,
ok.
+%% simple build and match variables
+t_build_and_match_variables(Config) when is_list(Config) ->
+ K0 = id(#{}),
+ K1 = id(1), V1 = id(a),
+ K2 = id(2), V2 = id(b),
+ K3 = id(3), V3 = id("c"),
+ K4 = id("4"), V4 = id("d"),
+ K5 = id(<<"5">>), V5 = id(<<"e">>),
+ K6 = id({"6",7}), V6 = id("f"),
+ K7 = id(#{ "a" => 3 }),
+ #{K1:=V1} = id(#{K1=>V1}),
+ #{K1:=V1,K2:=V2} = id(#{K1=>V1,K2=>V2}),
+ #{K1:=V1,K2:=V2,K3:=V3} = id(#{K1=>V1,K2=>V2,K3=>V3}),
+ #{K1:=V1,K2:=V2,K3:=V3,K4:=V4} = id(#{K1=>V1,K2=>V2,K3=>V3,K4=>V4}),
+ #{K1:=V1,K2:=V2,K3:=V3,K4:=V4,K5:=V5} = id(#{K1=>V1,K2=>V2,K3=>V3,K4=>V4,K5=>V5}),
+ #{K1:=V1,K2:=V2,K3:=V3,K4:=V4,K5:=V5,K6:=V6} = id(#{K1=>V1,K2=>V2,K3=>V3,K4=>V4,K5=>V5,K6=>V6}),
+
+ #{K5:=X,K5:=X=3,K4:=4} = id(#{K5=>3,K4=>4}),
+ #{K5:=X,<<"5">>:=X=3,K4:=4} = id(#{K5=>3,K4=>4}),
+ #{K5:=X,<<"5">>:=X=3,K4:=4} = id(#{<<"5">>=>3,K4=>4}),
+
+ #{ K4:=#{ K3:=#{K1:=V1, K2:=V2}}, K5:=V5} =
+ id(#{ K5=>V5, K4=>#{ K3=>#{K2 => V2, K1 => V1}}}),
+ #{ K4 := #{ K5 := Res }, K6 := Res} = id(#{K4=>#{K5 => 99}, K6 => 99}),
+
+ %% has keys
+ #{a :=_,b :=_,K1:=_,K2:=_,K3:=V3,K4:=ResKey,K4:=ResKey,"4":=ResKey,"4":="ok"} =
+ id(#{ a=>1, b=>1, K1=>V1, K2=>V2, K3=>V3, K4=>"nope", "4"=>"ok" }),
+
+ %% function
+ ok = match_function_map_neg_keys(#{ -1 => a, -2 => b, -3 => c }),
+
+ %% map key
+ #{ K0 := 42 } = id(#{ K0 => 42 }),
+ #{ K7 := 42 } = id(#{ K7 => 42 }),
+
+ %% nil key
+ KNIL = id([]),
+ #{KNIL:=ok,1:=2} = id(#{KNIL=>ok,1=>2}),
+
+ Bin = <<0:258>>,
+ #{ Bin := "three" } = id(#{<<0:258>> =>"three"}),
+
+ %% error case
+ {'EXIT',{{badmatch,_},_}} = (catch (#{K5:=3,x:=2} = id(#{K5=>3}))),
+ {'EXIT',{{badmatch,_},_}} = (catch (#{K5:=2} = id(#{K5=>3}))),
+ {'EXIT',{{badmatch,_},_}} = (catch (#{K5:=3} = id({a,b,c}))),
+ {'EXIT',{{badmatch,_},_}} = (catch (#{K5:=3} = id(#{K6=>3}))),
+ {'EXIT',{{badmatch,_},_}} = (catch (#{K5:=3} = id(K7))),
+ {'EXIT',{{badmatch,_},_}} = (catch (#{K7:=3} = id(#{K7=>42}))),
+ ok.
+
+
+match_function_map_neg_keys(#{ -1 := a, -2 := b, -3 := c }) -> ok.
+
+t_update_assoc_variables(Config) when is_list(Config) ->
+ K1 = id(1),
+ K2 = id(2),
+ K3 = id(3.0),
+ K4 = id(4),
+ K5 = id(5),
+ K6 = id(2.0),
+
+ M0 = #{K1=>a,K2=>b,K3=>c,K4=>d,K5=>e},
+
+ M1 = M0#{K1=>42,K2=>100,K4=>[a,b,c]},
+ #{1:=42,2:=100,3.0:=c,4:=[a,b,c],5:=e} = M1,
+ #{1:=42,2:=b,4:=d,5:=e,2.0:=100,K3:=c,4.0:=[a,b,c]} = M0#{1.0=>float,1:=42,2.0=>wrong,K6=>100,4.0=>[a,b,c]},
+
+ M2 = M0#{K3=>new},
+ #{1:=a,2:=b,K3:=new,4:=d,5:=e} = M2,
+ M2 = M0#{3.0:=wrong,K3=>new},
+
+ #{ <<0:258>> := val } = id(M0#{<<0:258>> => val}), %% binary limitation
+
+ %% Errors cases.
+ BadMap = id(badmap),
+ {'EXIT',{badarg,_}} = (catch BadMap#{nonexisting=>val}),
+ {'EXIT',{badarg,_}} = (catch <<>>#{nonexisting=>val}),
+ ok.
+
+t_update_exact_variables(Config) when is_list(Config) ->
+ K1 = id(1),
+ K2 = id(2),
+ K3 = id(3.0),
+ K4 = id(4),
+
+ M0 = id(#{1=>a,2=>b,3.0=>c,4=>d,5=>e}),
+
+ M1 = M0#{K1:=42,K2:=100,K4:=[a,b,c]},
+ #{1:=42,2:=100,3.0:=c,K4:=[a,b,c],5:=e} = M1,
+ M1 = M0#{K1:=wrong,1:=also_wrong,K1=>42,2=>wrong,K2:=100,4:=[a,b,c]},
+
+ M2 = M0#{K3:=new},
+ #{1:=a,K2:=b,3.0:=new,K4:=d,5:=e} = M2,
+ M2 = M0#{3.0=>wrong,K3:=new},
+ true = M2 =/= M0#{3=>right,3.0:=new},
+ #{ 3 := right, 3.0 := new } = M0#{3=>right,K3:=new},
+
+ M3 = id(#{ 1 => val}),
+ #{1 := update2,1.0 := new_val4} = M3#{
+ 1.0 => new_val1, K1 := update, K1=> update3,
+ K1 := update2, 1.0 := new_val2, 1.0 => new_val3,
+ 1.0 => new_val4 },
+
+ #{ "wat" := 3, 2 := a } = id(#{ "wat" => 1, K2 => 2 }#{ K2 := a, "wat" := 3 }),
+
+ %% Errors cases.
+ {'EXIT',{badarg,_}} = (catch ((id(nil))#{ a := b })),
+ {'EXIT',{badarg,_}} = (catch M0#{nonexisting:=val}),
+ {'EXIT',{badarg,_}} = (catch M0#{1.0:=v,1.0=>v2}),
+ {'EXIT',{badarg,_}} = (catch M0#{42.0:=v,42:=v2}),
+ {'EXIT',{badarg,_}} = (catch M0#{42=>v1,42.0:=v2,42:=v3}),
+ {'EXIT',{badarg,_}} = (catch <<>>#{nonexisting:=val}),
+ {'EXIT',{badarg,_}} = (catch M0#{<<0:257>> := val}), %% limitation
+ ok.
+
+t_nested_pattern_expressions(Config) when is_list(Config) ->
+ K1 = id("hello"),
+ %K2 = id({ok}),
+ [_,_,#{ <<"hi">> := wat, K1 := 42 }|_] = id([k,k,#{<<"hi">> => wat, K1 => 42}]),
+ [_,_,#{ -1 := wat, K1 := 42 }|_] = id([k,k,#{-1 => wat, K1 => 42}]),
+ [_,_,{#{ -1 := #{ {-3,<<0:300>>} := V1 }, K1 := 42 },3}|_] = id([k,k,{#{-1 => #{{-3,<<0:300>>}=>"hi"}, K1 => 42},3}]),
+ "hi" = V1,
+ %[k,#{ {-1,K1,[]} := {wat,K1}, K2 := 42 }|_] = id([k,#{{-1,K1,[]} => {wat,K1}, K2 => 42}]),
+ %[k,#{ [-1,K2,[]] := {wat,K1}, K1 := 42 }|_] = id([k,#{[-1,K2,[]] => {wat,K1}, K1 => 42}]),
+
+ M0 = id(#{ <<33:333>> => 1, <<332:333>> => ok, a => ok, wat => yep, watzor => ok }),
+ F0 = map_nested_pattern_funs(M0),
+ F1 = F0(wat),
+ F2 = F1(watzor),
+ {yep,ok} = F2(M0),
+ ok.
+
+map_nested_pattern_funs(M) ->
+ K0 = id(a),
+ fun(K1) ->
+ case M of
+ #{ K0 := ok, K1 := yep, <<33:333>> := 1 } ->
+ fun(K2) ->
+ case M of
+ #{ K2 := ok, K1 := yep, <<33:333>> := 1 } ->
+ fun
+ (#{ <<332:333>> := ok, K1 := V1, K2 := V2 }) ->
+ {V1,V2}
+ end
+ end
+ end
+ end
+ end.
+
+t_guard_update_variables(Config) when is_list(Config) ->
+ error = map_guard_update_variables(n,#{},#{}),
+ first = map_guard_update_variables(x,#{}, #{x=>first}),
+ second = map_guard_update_variables(x,#{y=>old}, #{x=>second,y=>old}),
+ third = map_guard_update_variables(x,#{x=>old,y=>old}, #{x=>third,y=>old}),
+ fourth = map_guard_update_variables(x,#{x=>old,y=>old}, #{x=>4,y=>new}),
+ ok.
+
+map_guard_update_variables(K,M1,M2) when M1#{K=>first} =:= M2 -> first;
+map_guard_update_variables(K,M1,M2) when M1#{K=>second} =:= M2 -> second;
+map_guard_update_variables(K,M1,M2) when M1#{K:=third} =:= M2 -> third;
+map_guard_update_variables(K,M1,M2) when M1#{K:=4,y=>new} =:= M2 -> fourth;
+map_guard_update_variables(_,_,_) -> error.
+
+t_guard_sequence_variables(Config) when is_list(Config) ->
+ {1,"a"} = map_guard_sequence_var_1(a,#{seq=>1,a=>id("a"),b=>no}),
+ {2,"b"} = map_guard_sequence_var_1(b,#{seq=>2,b=>id("b"),a=>no}),
+ {3,"c"} = map_guard_sequence_var_1(a,#{seq=>3,a=>id("c"),b=>no}),
+ {4,"d"} = map_guard_sequence_var_1(b,#{seq=>4,b=>id("d"),a=>no}),
+ {4,4} = map_guard_sequence_var_1(seq,#{seq=>4}),
+ {4,4,y} = map_guard_sequence_var_1(seq,#{seq=>4,b=>id("d"),a=>y}),
+ {5,"d"} = map_guard_sequence_var_1(b,#{seq=>5,b=>id("d"),a=>y}),
+
+ %% error case
+ {'EXIT',{{case_clause,_},_}} = (catch map_guard_sequence_var_1("a",#{seq=>4,val=>id("e")})),
+ ok.
+
+
+map_guard_sequence_var_1(K,M) ->
+ case M of
+ #{seq:=1=Seq, K:=Val} -> {Seq,Val};
+ #{seq:=2=Seq, K:=Val} -> {Seq,Val};
+ #{seq:=3=Seq, K:=Val} -> {Seq,Val};
+ #{K:=4=Seq, K:=Val1,a:=Val2} -> {Seq,Val1,Val2};
+ #{seq:=4=Seq, K:=Val} -> {Seq,Val};
+ #{K:=4=Seq, K:=Val} -> {Seq,Val};
+ #{seq:=5=Seq, K:=Val} -> {Seq,Val}
+ end.
+
+
+t_guard_sequence_mixed(Config) when is_list(Config) ->
+ M0 = id(#{ a=>1, b=>1, c=>1, d=>1, e=>1, f=>1, g=>1, h=>1 }),
+ M1 = id(M0#{ d := 3 }),
+ 1 = map_guard_sequence_mixed(a,d,M1),
+ M2 = id(M1#{ b := 2, d := 4, h := 2 }),
+ 2 = map_guard_sequence_mixed(a,d,M2),
+ M3 = id(M2#{ b := 3, e := 5, g := 3 }),
+ 3 = map_guard_sequence_mixed(a,e,M3),
+ M4 = id(M3#{ c := 4, e := 6, h := 1 }),
+ 4 = map_guard_sequence_mixed(a,e,M4),
+ M5 = id(M4#{ c := 5, f := 7, g := 2 }),
+ 5 = map_guard_sequence_mixed(a,f,M5),
+ M6 = id(M5#{ c := 6, f := 8, h := 3 }),
+ 6 = map_guard_sequence_mixed(a,f,M6),
+
+ %% error case
+ {'EXIT',{{case_clause,_},_}} = (catch map_guard_sequence_mixed(a,b,M0)),
+ ok.
+
+map_guard_sequence_mixed(K1,K2,M) ->
+ case M of
+ #{ K1 := 1, b := 1, K2 := 3, g := 1} -> 1;
+ #{ K1 := 1, b := 2, K2 := 4, h := 2} -> 2;
+ #{ K1 := 1, b := 3, K2 := 5, g := 3} -> 3;
+ #{ K1 := 1, c := 4, K2 := 6, h := 1} -> 4;
+ #{ K1 := 1, c := 5, K2 := 7, g := 2} -> 5;
+ #{ K1 := 1, c := 6, K2 := 8, h := 3} -> 6
+ end.
+
+
+
+t_frequency_table(Config) when is_list(Config) ->
+ random:seed({13,1337,54}), % pseudo random
+ N = 100000,
+ Ts = rand_terms(N),
+ #{ n:=N, tf := Tf } = frequency_table(Ts,#{ n=>0, tf => #{}}),
+ ok = check_frequency(Ts,Tf),
+ ok.
+
+
+frequency_table([T|Ts], M) ->
+ case M of
+ #{ n := N, tf := #{ T := C } = F } ->
+ frequency_table(Ts,M#{ n := N + 1, tf := F#{ T := C + 1 }});
+ #{ n := N, tf := F } ->
+ frequency_table(Ts,M#{ n := N + 1, tf := F#{ T => 1 }})
+ end;
+frequency_table([], M) -> M.
+
+
+check_frequency(Ts,Tf) ->
+ check_frequency(Ts,Tf,dict:new()).
+
+check_frequency([T|Ts],Tf,D) ->
+ case dict:find(T,D) of
+ error -> check_frequency(Ts,Tf,dict:store(T,1,D));
+ {ok,C} -> check_frequency(Ts,Tf,dict:store(T,C+1,D))
+ end;
+check_frequency([],Tf,D) ->
+ validate_frequency(dict:to_list(D),Tf).
+
+validate_frequency([{T,C}|Fs],Tf) ->
+ case Tf of
+ #{ T := C } -> validate_frequency(Fs,Tf);
+ _ -> error
+ end;
+validate_frequency([], _) -> ok.
+
+
+%% aux
+
+rand_terms(0) -> [];
+rand_terms(N) -> [rand_term()|rand_terms(N-1)].
+
+rand_term() ->
+ case random:uniform(6) of
+ 1 -> rand_binary();
+ 2 -> rand_number();
+ 3 -> rand_atom();
+ 4 -> rand_tuple();
+ 5 -> rand_list();
+ 6 -> rand_map()
+ end.
+
+rand_binary() ->
+ case random:uniform(3) of
+ 1 -> <<>>;
+ 2 -> <<"hi">>;
+ 3 -> <<"message text larger than 64 bytes. yep, message text larger than 64 bytes.">>
+ end.
+
+rand_number() ->
+ case random:uniform(3) of
+ 1 -> random:uniform(5);
+ 2 -> float(random:uniform(5));
+ 3 -> 1 bsl (63 + random:uniform(3))
+ end.
+
+rand_atom() ->
+ case random:uniform(3) of
+ 1 -> hi;
+ 2 -> some_atom;
+ 3 -> some_other_atom
+ end.
+
+
+rand_tuple() ->
+ case random:uniform(3) of
+ 1 -> {ok, rand_term()}; % careful
+ 2 -> {1, 2, 3};
+ 3 -> {<<"yep">>, 1337}
+ end.
+
+rand_list() ->
+ case random:uniform(3) of
+ 1 -> "hi";
+ 2 -> [1,rand_term()]; % careful
+ 3 -> [improper|list]
+ end.
+
+rand_map() ->
+ case random:uniform(3) of
+ 1 -> #{ hi => 3 };
+ 2 -> #{ wat => rand_term(), other => 3 }; % careful
+ 3 -> #{ hi => 42, other => 42, yet_anoter => 1337 }
+ end.
+
+
+
%% Use this function to avoid compile-time evaluation of an expression.
id(I) -> I.