stdlib: Modify ~w/~W when number of characters is limited

A bug fix: limited maps end with "...", not "...=>...".
A modification: wW separate pairs with " => ", not "=>".

When the output is limited on number of characters, the term is
balanced by wW the same way as is done with pP (see commit bc38638).

3 files changed, 71 insertions, 58 deletions

diff --git a/lib/stdlib/src/io_lib.erl b/lib/stdlib/src/io_lib.erl
index 17b6e9967c..7a520f17d9 100644
--- a/lib/stdlib/src/io_lib.erl
+++ b/lib/stdlib/src/io_lib.erl
@@ -65,6 +65,7 @@
 -export([print/1,print/4,indentation/2]).
 
 -export([write/1,write/2,write/3,nl/0,format_prompt/1,format_prompt/2]).
+-export([write_binary/2]).
 -export([write_atom/1,write_string/1,write_string/2,write_latin1_string/1,
          write_latin1_string/2, write_char/1, write_latin1_char/1]).
 
@@ -259,7 +260,8 @@ add_modifier(_, C) ->
 -spec write(Term) -> chars() when
       Term :: term().
 
-write(Term) -> write(Term, -1).
+write(Term) ->
+    write1(Term, -1, latin1).
 
 -spec write(term(), depth(), boolean()) -> chars().
 
@@ -281,9 +283,19 @@ write(Term, D, false) ->
 write(Term, Options) when is_list(Options) ->
     Depth = get_option(depth, Options, -1),
     Encoding = get_option(encoding, Options, epp:default_encoding()),
-    write1(Term, Depth, Encoding);
+    CharsLimit = get_option(chars_limit, Options, -1),
+    RecDefFun = no_fun,
+    case Depth of
+        0 -> "...";
+        _ when CharsLimit < 0 ->
+            write1(Term, Depth, Encoding);
+        _ when CharsLimit >= 0 ->
+            If = io_lib_pretty:intermediate
+                   (Term, Depth, CharsLimit, RecDefFun, Encoding, _Str=false),
+            io_lib_pretty:write(If)
+    end;
 write(Term, Depth) ->
-    write1(Term, Depth, latin1).
+    write(Term, [{depth, Depth}, {encoding, latin1}]).
 
 write1(_Term, 0, _E) -> "...";
 write1(Term, _D, _E) when is_integer(Term) -> integer_to_list(Term);
@@ -339,14 +351,14 @@ write_ref(Ref) ->
 write_map(Map, D, E) when is_integer(D) ->
     [$#,${,write_map_body(maps:to_list(Map), D, E),$}].
 
-write_map_body(_, 0, _E) -> "...";
+write_map_body(_, 1, _E) -> "...";
 write_map_body([], _, _E) -> [];
 write_map_body([{K,V}], D, E) -> write_map_assoc(K, V, D, E);
 write_map_body([{K,V}|KVs], D, E) ->
     [write_map_assoc(K, V, D, E),$, | write_map_body(KVs, D-1, E)].
 
 write_map_assoc(K, V, D, E) ->
-    [write1(K, D - 1, E),"=>",write1(V, D-1, E)].
+    [write1(K, D - 1, E)," => ",write1(V, D-1, E)].
 
 write_binary(B, D) when is_integer(D) ->
     [$<,$<,write_binary_body(B, D),$>,$>].
diff --git a/lib/stdlib/src/io_lib_pretty.erl b/lib/stdlib/src/io_lib_pretty.erl
index 785c602ac0..9b0000ded0 100644
--- a/lib/stdlib/src/io_lib_pretty.erl
+++ b/lib/stdlib/src/io_lib_pretty.erl
@@ -26,6 +26,9 @@
 
 -export([print/1,print/2,print/3,print/4,print/5,print/6]).
 
+%% To be used by io_lib only.
+-export([intermediate/6, write/1]).
+
 %%%
 %%% Exported functions
 %%%
@@ -573,10 +576,10 @@ print_length(<<_/bitstring>> = Bin, D, T, RF, Enc, Str) ->
                    end,
             {[$<,$<,S|"/utf8...>>"], 12 + length(S), 3, More};
         false when byte_size(Bin) < D ->
-            S = io_lib:write(Bin, D),
+            S = io_lib:write_binary(Bin, D),
             {{bin, S}, iolist_size(S), 0, no_more};
         false ->
-            S = io_lib:write(Bin, D),
+            S = io_lib:write_binary(Bin, D),
             More = fun(T1, Dd) ->
                            ?FUNCTION_NAME(Bin, D+Dd, T1, RF, Enc, Str)
                    end,
diff --git a/lib/stdlib/test/io_SUITE.erl b/lib/stdlib/test/io_SUITE.erl
index 9fdd7da4dc..e1a6f9031b 100644
--- a/lib/stdlib/test/io_SUITE.erl
+++ b/lib/stdlib/test/io_SUITE.erl
@@ -2053,19 +2053,19 @@ maps(_Config) ->
     %% in a map with more than one element.
 
     "#{}" = fmt("~w", [#{}]),
-    "#{a=>b}" = fmt("~w", [#{a=>b}]),
-    re_fmt(<<"#\\{(a=>b|c=>d),[.][.][.]=>[.][.][.]\\}">>,
-	     "~W", [#{a=>b,c=>d},2]),
-    re_fmt(<<"#\\{(a=>b|c=>d|e=>f),[.][.][.]=>[.][.][.],[.][.][.]\\}">>,
-	   "~W", [#{a=>b,c=>d,e=>f},2]),
+    "#{a => b}" = fmt("~w", [#{a=>b}]),
+    re_fmt(<<"#\\{(a => b),[.][.][.]\\}">>,
+	     "~W", [#{a => b,c => d},2]),
+    re_fmt(<<"#\\{(a => b),[.][.][.]\\}">>,
+	   "~W", [#{a => b,c => d,e => f},2]),
 
     "#{}" = fmt("~p", [#{}]),
-    "#{a => b}" = fmt("~p", [#{a=>b}]),
-    "#{...}" = fmt("~P", [#{a=>b},1]),
+    "#{a => b}" = fmt("~p", [#{a => b}]),
+    "#{...}" = fmt("~P", [#{a => b},1]),
     re_fmt(<<"#\\{(a => b|c => d),[.][.][.]\\}">>,
-	   "~P", [#{a=>b,c=>d},2]),
+	   "~P", [#{a => b,c => d},2]),
     re_fmt(<<"#\\{(a => b|c => d|e => f),[.][.][.]\\}">>,
-	   "~P", [#{a=>b,c=>d,e=>f},2]),
+	   "~P", [#{a => b,c => d,e => f},2]),
 
     List = [{I,I*I} || I <- lists:seq(1, 20)],
     Map = maps:from_list(List),
@@ -2493,25 +2493,27 @@ pp(Term, Depth) ->
 otp_14983(_Config) ->
     trunc_depth(-1),
     trunc_depth(10),
+    trunc_depth_p(-1),
+    trunc_depth_p(10),
     ok.
 
 trunc_depth(D) ->
-    "..." = tp("", D, 0),
-    "[]" = tp("", D, 1),
+    "..." = trp("", D, 0),
+    "[]" = trp("", D, 1),
 
-    "#{}" = tp(#{}, D, 1),
-    "#{a => 1}" = tp(#{a => 1}, D, 7),
-    "#{...}" = tp(#{a => 1}, D, 5),
-    "#{a => 1}" = tp(#{a => 1}, D, 6),
+    "#{}" = trp(#{}, D, 1),
+    "#{a => 1}" = trp(#{a => 1}, D, 7),
+    "#{...}" = trp(#{a => 1}, D, 5),
+    "#{a => 1}" = trp(#{a => 1}, D, 6),
     A = lists:seq(1, 1000),
     M = #{A => A, {A,A} => {A,A}},
-    "#{...}" = tp(M, D, 6),
-    "#{{...} => {...},...}" = tp(M, D, 7),
-    "#{{[...],...} => {[...],...},...}" = tp(M, D, 22),
-    "#{{[...],...} => {[...],...},[...] => [...]}" = tp(M, D, 31),
-    "#{{[...],...} => {[...],...},[...] => [...]}" = tp(M, D, 33),
+    "#{...}" = trp(M, D, 6),
+    "#{{...} => {...},...}" = trp(M, D, 7),
+    "#{{[...],...} => {[...],...},...}" = trp(M, D, 22),
+    "#{{[...],...} => {[...],...},[...] => [...]}" = trp(M, D, 31),
+    "#{{[...],...} => {[...],...},[...] => [...]}" = trp(M, D, 33),
     "#{{[1|...],[...]} => {[1|...],[...]},[1|...] => [...]}" =
-        tp(M, D, 50),
+        trp(M, D, 50),
 
     "..." = trp({c, 1, 2}, D, 0),
     "{...}" = trp({c, 1, 2}, D, 1),
@@ -2522,42 +2524,38 @@ trunc_depth(D) ->
     "#c{f1 = [1,2|...],f2 = [1|...]}" = trp({c, A, A}, D, 31),
     "#c{f1 = [1,2,3|...],f2 = [1,2|...]}" = trp({c, A, A}, D, 32),
 
-    "..." = tp({}, D, 0),
-    "{}" = tp({}, D, 1),
+    "..." = trp({}, D, 0),
+    "{}" = trp({}, D, 1),
     T = {A, A, A},
-    "{...}" = tp(T, D, 5),
-    "{[...],...}" = tp(T, D, 6),
-    "{[1|...],[...],...}" = tp(T, D, 12),
-    "{[1,2|...],[1|...],...}" = tp(T, D, 20),
-    "{[1,2|...],[1|...],[...]}" = tp(T, D, 21),
-    "{[1,2,3|...],[1,2|...],[1|...]}" = tp(T, D, 28),
-
-    "{[1],[1,2|...]}" = tp({[1],[1,2,3,4]}, D, 14),
-    "[...]" = tp("abcdefg", D, 4),
-    "\"abc\"..." = tp("abcdefg", D, 5),
-    "\"abcdef\"..." = tp("abcdefg", D, 8),
-    "\"abcdefg\"" = tp("abcdefg", D, 9),
-    "\"abcdefghijkl\"" = tp("abcdefghijkl", D, -1),
-
+    "{...}" = trp(T, D, 5),
+    "{[...],...}" = trp(T, D, 6),
+    "{[1|...],[...],...}" = trp(T, D, 12),
+    "{[1,2|...],[1|...],...}" = trp(T, D, 20),
+    "{[1,2|...],[1|...],[...]}" = trp(T, D, 21),
+    "{[1,2,3|...],[1,2|...],[1|...]}" = trp(T, D, 28),
+
+    "{[1],[1,2|...]}" = trp({[1],[1,2,3,4]}, D, 14).
+
+trunc_depth_p(D) ->
+    "[...]" = trp("abcdefg", D, 4),
+    "\"abc\"..." = trp("abcdefg", D, 5),
+    "\"abcdef\"..." = trp("abcdefg", D, 8),
+    "\"abcdefg\"" = trp("abcdefg", D, 9),
+    "\"abcdefghijkl\"" = trp("abcdefghijkl", D, -1),
     AZ = lists:seq($A, $Z),
     AZb = list_to_binary(AZ),
     AZbS = "<<\"" ++ AZ ++ "\">>",
-    AZbS = tp(AZb, D, -1),
-    "<<\"ABCDEFGH\"...>>" = tp(AZb, D, 17), % 4 chars even if D = -1...
-    "<<\"ABCDEFGHIJKL\"...>>" = tp(AZb, D, 18),
+    AZbS = trp(AZb, D, -1),
+    "<<\"ABCDEFGH\"...>>" = trp(AZb, D, 17), % 4 chars even if D = -1...
+    "<<\"ABCDEFGHIJKL\"...>>" = trp(AZb, D, 18),
     B1 = <<"abcdef",0:8>>,
-    "<<\"ab\"...>>" = tp(B1, D, 8),
-    "<<\"abcdef\"...>>" = tp(B1, D, 14),
-    %% Tricky. Much more than 15 characters:
-    "<<97,98,99,100,101,102,0>>" = tp(B1, D, 15),
-    "<<97,98,99,100,101,102,0>>" = tp(B1, D, -1),
+    "<<\"ab\"...>>" = trp(B1, D, 8),
+    "<<\"abcdef\"...>>" = trp(B1, D, 14),
+    "<<97,98,99,100,101,102,0>>" = trp(B1, D, -1),
     B2 = <<AZb/binary,0:8>>,
-    "<<\"AB\"...>>" = tp(B2, D, 8),
-    "<<\"ABCDEFGH\"...>>" = tp(B2, D, 14),
-    "<<65,66,67,68,69,70,71,72,0>>" = tp(<<"ABCDEFGH",0:8>>, D, -1).
-
-tp(Term, D, T) ->
-    trp(Term, D, T, fun(_, _) -> no end).
+    "<<\"AB\"...>>" = trp(B2, D, 8),
+    "<<\"ABCDEFGH\"...>>" = trp(B2, D, 14),
+    "<<65,66,67,68,69,70,71,72,0>>" = trp(<<"ABCDEFGH",0:8>>, D, -1).
 
 trp(Term, D, T) ->
     trp(Term, D, T, fun rfd/2).