Merge branch 'siri/string-new-api'

* siri/string-new-api: (28 commits)
  hipe (test): Do not use deprecated functions in string(3)
  dialyzer (test): Do not use deprecated functions in string(3)
  eunit (test): Do not use deprecated functions in string(3)
  system (test): Do not use deprecated functions in string(3)
  system (test): Do not use deprecated functions in string(3)
  mnesia (test): Do not use deprecated functions in string(3)
  Deprecate old string functions
  observer: Do not use deprecated functions in string(3)
  common_test: Do not use deprecated functions in string(3)
  eldap: Do not use deprecated functions in string(3)
  et: Do not use deprecated functions in string(3)
  os_mon: Do not use deprecated functions in string(3)
  debugger: Do not use deprecated functions in string(3)
  runtime_tools: Do not use deprecated functions in string(3)
  asn1: Do not use deprecated functions in string(3)
  compiler: Do not use deprecated functions in string(3)
  sasl: Do not use deprecated functions in string(3)
  reltool: Do not use deprecated functions in string(3)
  kernel: Do not use deprecated functions in string(3)
  hipe: Do not use deprecated functions in string(3)
  ...

Conflicts:
	lib/eunit/src/eunit_lib.erl
	lib/observer/src/crashdump_viewer.erl
	lib/reltool/src/reltool_target.erl

14 files changed, 116 insertions, 450 deletions

diff --git a/lib/stdlib/doc/src/string.xml b/lib/stdlib/doc/src/string.xml
index 9d5edd9ecf..130fc74a28 100644
--- a/lib/stdlib/doc/src/string.xml
+++ b/lib/stdlib/doc/src/string.xml
@@ -109,10 +109,8 @@
     <p>This module has been reworked in Erlang/OTP 20 to
     handle <seealso marker="unicode#type-chardata">
     <c>unicode:chardata()</c></seealso> and operate on grapheme
-    clusters. The <seealso marker="#oldapi"> <c>old
-    functions</c></seealso> that only work on Latin-1 lists as input
-    are still available but should not be
-    used. They will be deprecated in Erlang/OTP 21.
+    clusters. The <c>old functions</c> that only work on Latin-1 lists as input
+    are kept for backwards compatibility reasons but should not be used.
     </p>
   </description>
 
@@ -594,7 +592,7 @@ ÖÄÅ</pre>
 	  or <c>both</c>, indicates from which direction characters
 	  are to be removed.
 	</p>
-	<p> Default <c><anno>Characters</anno></c> are the set of
+	<p> Default <c><anno>Characters</anno></c> is the set of
 	nonbreakable whitespace codepoints, defined as
 	Pattern_White_Space in
 	<url href="http://unicode.org/reports/tr31/">Unicode Standard Annex #31</url>.
@@ -631,393 +629,5 @@ ÖÄÅ</pre>
     </func>
 
   </funcs>
-
-  <section>
-    <marker id="oldapi"/>
-    <title>Obsolete API functions</title>
-    <p>Here follows the function of the old API.
-    These functions only work on a list of Latin-1 characters.
-    </p>
-    <note><p>
-      The functions are kept for backward compatibility, but are
-      not recommended.
-      They will be deprecated in Erlang/OTP 21.
-    </p>
-    <p>Any undocumented functions in <c>string</c> are not to be used.</p>
-    </note>
-  </section>
-
-  <funcs>
-    <func>
-      <name name="centre" arity="2"/>
-      <name name="centre" arity="3"/>
-      <fsummary>Center a string.</fsummary>
-      <desc>
-        <p>Returns a string, where <c><anno>String</anno></c> is centered in the
-          string and surrounded by blanks or <c><anno>Character</anno></c>.
-	  The resulting string has length <c><anno>Number</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#pad/3"><c>pad/3</c></seealso>.
-	</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="chars" arity="2"/>
-      <name name="chars" arity="3"/>
-      <fsummary>Return a string consisting of numbers of characters.</fsummary>
-      <desc>
-        <p>Returns a string consisting of <c><anno>Number</anno></c> characters
-          <c><anno>Character</anno></c>. Optionally, the string can end with
-          string <c><anno>Tail</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="lists#duplicate/2"><c>lists:duplicate/2</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="chr" arity="2"/>
-      <fsummary>Return the index of the first occurrence of
-        a character in a string.</fsummary>
-      <desc>
-        <p>Returns the index of the first occurrence of
-          <c><anno>Character</anno></c> in <c><anno>String</anno></c>. Returns
-          <c>0</c> if <c><anno>Character</anno></c> does not occur.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#find/2"><c>find/2</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="concat" arity="2"/>
-      <fsummary>Concatenate two strings.</fsummary>
-      <desc>
-        <p>Concatenates <c><anno>String1</anno></c> and
-          <c><anno>String2</anno></c> to form a new string
-          <c><anno>String3</anno></c>, which is returned.</p>
-	<p>
-	  This function is <seealso marker="#oldapi">obsolete</seealso>.
-	  Use <c>[<anno>String1</anno>, <anno>String2</anno>]</c> as
-	  <c>Data</c> argument, and call
-	  <seealso marker="unicode#characters_to_list/2">
-	  <c>unicode:characters_to_list/2</c></seealso> or
-	  <seealso marker="unicode#characters_to_binary/2">
-	  <c>unicode:characters_to_binary/2</c></seealso>
-	  to flatten the output.
-	</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="copies" arity="2"/>
-      <fsummary>Copy a string.</fsummary>
-      <desc>
-        <p>Returns a string containing <c><anno>String</anno></c> repeated
-          <c><anno>Number</anno></c> times.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="lists#duplicate/2"><c>lists:duplicate/2</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="cspan" arity="2"/>
-      <fsummary>Span characters at start of a string.</fsummary>
-      <desc>
-        <p>Returns the length of the maximum initial segment of
-          <c><anno>String</anno></c>, which consists entirely of characters
-          not from <c><anno>Chars</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#take/3"><c>take/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:cspan("\t    abcdef", " \t").
-0</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="join" arity="2"/>
-      <fsummary>Join a list of strings with separator.</fsummary>
-      <desc>
-        <p>Returns a string with the elements of <c><anno>StringList</anno></c>
-          separated by the string in <c><anno>Separator</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="lists#join/2"><c>lists:join/2</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> join(["one", "two", "three"], ", ").
-"one, two, three"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="left" arity="2"/>
-      <name name="left" arity="3"/>
-      <fsummary>Adjust left end of a string.</fsummary>
-      <desc>
-        <p>Returns <c><anno>String</anno></c> with the length adjusted in
-          accordance with <c><anno>Number</anno></c>. The left margin is
-          fixed. If <c>length(<anno>String</anno>)</c> &lt;
-          <c><anno>Number</anno></c>, then <c><anno>String</anno></c> is padded
-          with blanks or <c><anno>Character</anno></c>s.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#pad/2"><c>pad/2</c></seealso> or
-	<seealso marker="#pad/3"><c>pad/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:left("Hello",10,$.).
-"Hello....."</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="len" arity="1"/>
-      <fsummary>Return the length of a string.</fsummary>
-      <desc>
-        <p>Returns the number of characters in <c><anno>String</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#length/1"><c>length/1</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="rchr" arity="2"/>
-      <fsummary>Return the index of the last occurrence of
-        a character in a string.</fsummary>
-      <desc>
-        <p>Returns the index of the last occurrence of
-          <c><anno>Character</anno></c> in <c><anno>String</anno></c>. Returns
-          <c>0</c> if <c><anno>Character</anno></c> does not occur.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#find/3"><c>find/3</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="right" arity="2"/>
-      <name name="right" arity="3"/>
-      <fsummary>Adjust right end of a string.</fsummary>
-      <desc>
-        <p>Returns <c><anno>String</anno></c> with the length adjusted in
-          accordance with <c><anno>Number</anno></c>. The right margin is
-          fixed. If the length of <c>(<anno>String</anno>)</c> &lt;
-          <c><anno>Number</anno></c>, then <c><anno>String</anno></c> is padded
-          with blanks or <c><anno>Character</anno></c>s.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#pad/3"><c>pad/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:right("Hello", 10, $.).
-".....Hello"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="rstr" arity="2"/>
-      <fsummary>Find the index of a substring.</fsummary>
-      <desc>
-        <p>Returns the position where the last occurrence of
-          <c><anno>SubString</anno></c> begins in <c><anno>String</anno></c>.
-          Returns <c>0</c> if <c><anno>SubString</anno></c>
-          does not exist in <c><anno>String</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#find/3"><c>find/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:rstr(" Hello Hello World World ", "Hello World").
-8</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="span" arity="2"/>
-      <fsummary>Span characters at start of a string.</fsummary>
-      <desc>
-        <p>Returns the length of the maximum initial segment of
-          <c><anno>String</anno></c>, which consists entirely of characters
-          from <c><anno>Chars</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#take/2"><c>take/2</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:span("\t    abcdef", " \t").
-5</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="str" arity="2"/>
-      <fsummary>Find the index of a substring.</fsummary>
-      <desc>
-        <p>Returns the position where the first occurrence of
-          <c><anno>SubString</anno></c> begins in <c><anno>String</anno></c>.
-          Returns <c>0</c> if <c><anno>SubString</anno></c>
-          does not exist in <c><anno>String</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#find/2"><c>find/2</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:str(" Hello Hello World World ", "Hello World").
-8</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="strip" arity="1"/>
-      <name name="strip" arity="2"/>
-      <name name="strip" arity="3"/>
-      <fsummary>Strip leading or trailing characters.</fsummary>
-      <desc>
-        <p>Returns a string, where leading or trailing, or both, blanks or a
-          number of <c><anno>Character</anno></c> have been removed.
-          <c><anno>Direction</anno></c>, which can be <c>left</c>, <c>right</c>,
-          or <c>both</c>, indicates from which direction blanks are to be
-          removed. <c>strip/1</c> is equivalent to
-          <c>strip(String, both)</c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#trim/3"><c>trim/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:strip("...Hello.....", both, $.).
-"Hello"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="sub_string" arity="2"/>
-      <name name="sub_string" arity="3"/>
-      <fsummary>Extract a substring.</fsummary>
-      <desc>
-        <p>Returns a substring of <c><anno>String</anno></c>, starting at
-          position <c><anno>Start</anno></c> to the end of the string, or to
-          and including position <c><anno>Stop</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#slice/3"><c>slice/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-sub_string("Hello World", 4, 8).
-"lo Wo"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="substr" arity="2"/>
-      <name name="substr" arity="3"/>
-      <fsummary>Return a substring of a string.</fsummary>
-      <desc>
-        <p>Returns a substring of <c><anno>String</anno></c>, starting at
-          position <c><anno>Start</anno></c>, and ending at the end of the
-          string or at length <c><anno>Length</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#slice/3"><c>slice/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> substr("Hello World", 4, 5).
-"lo Wo"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="sub_word" arity="2"/>
-      <name name="sub_word" arity="3"/>
-      <fsummary>Extract subword.</fsummary>
-      <desc>
-        <p>Returns the word in position <c><anno>Number</anno></c> of
-          <c><anno>String</anno></c>. Words are separated by blanks or
-          <c><anno>Character</anno></c>s.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#nth_lexeme/3"><c>nth_lexeme/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:sub_word(" Hello old boy !",3,$o).
-"ld b"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="to_lower" arity="1" clause_i="1"/>
-      <name name="to_lower" arity="1" clause_i="2"/>
-      <name name="to_upper" arity="1" clause_i="1"/>
-      <name name="to_upper" arity="1" clause_i="2"/>
-      <fsummary>Convert case of string (ISO/IEC 8859-1).</fsummary>
-      <type variable="String" name_i="1"/>
-      <type variable="Result" name_i="1"/>
-      <type variable="Char"/>
-      <type variable="CharResult"/>
-      <desc>
-        <p>The specified string or character is case-converted. Notice that
-          the supported character set is ISO/IEC 8859-1 (also called Latin 1);
-          all values outside this set are unchanged</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso> use
-	<seealso marker="#lowercase/1"><c>lowercase/1</c></seealso>,
-	<seealso marker="#uppercase/1"><c>uppercase/1</c></seealso>,
-	<seealso marker="#titlecase/1"><c>titlecase/1</c></seealso> or
-	<seealso marker="#casefold/1"><c>casefold/1</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="tokens" arity="2"/>
-      <fsummary>Split string into tokens.</fsummary>
-      <desc>
-        <p>Returns a list of tokens in <c><anno>String</anno></c>, separated
-          by the characters in <c><anno>SeparatorList</anno></c>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> tokens("abc defxxghix jkl", "x ").
-["abc", "def", "ghi", "jkl"]</code>
-        <p>Notice that, as shown in this example, two or more
-          adjacent separator characters in <c><anno>String</anno></c>
-          are treated as one. That is, there are no empty
-          strings in the resulting list of tokens.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#lexemes/2"><c>lexemes/2</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="words" arity="1"/>
-      <name name="words" arity="2"/>
-      <fsummary>Count blank separated words.</fsummary>
-      <desc>
-        <p>Returns the number of words in <c><anno>String</anno></c>, separated
-          by blanks or <c><anno>Character</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#lexemes/2"><c>lexemes/2</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> words(" Hello old boy!", $o).
-4</code>
-      </desc>
-    </func>
-  </funcs>
-
-  <section>
-    <title>Notes</title>
-    <p>Some of the general string functions can seem to overlap each
-      other. The reason is that this string package is the
-      combination of two earlier packages and all functions of
-      both packages have been retained.</p>
-  </section>
-
 </erlref>
 
diff --git a/lib/stdlib/src/epp.erl b/lib/stdlib/src/epp.erl
index 31d0d499e3..00e6a10d8a 100644
--- a/lib/stdlib/src/epp.erl
+++ b/lib/stdlib/src/epp.erl
@@ -479,7 +479,7 @@ com_enc(_B, _Fun, _N, L, Ps) ->
     com_enc_end([L | Ps]).
 
 com_enc_end(Ps0) ->
-    Ps = lists:reverse([lists:reverse(string:to_lower(P)) || P <- Ps0]),
+    Ps = lists:reverse([lists:reverse(lowercase(P)) || P <- Ps0]),
     com_encoding(Ps).
 
 com_encoding(["latin","1"|_]) ->
@@ -489,6 +489,9 @@ com_encoding(["utf","8"|_]) ->
 com_encoding(_) ->
     throw(no). % Don't try any further
 
+lowercase(S) ->
+    unicode:characters_to_list(string:lowercase(S)).
+
 normalize_typed_record_fields([]) ->
     {typed, []};
 normalize_typed_record_fields(Fields) ->
diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index 9cd4727dc3..f58cb35cea 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -3910,10 +3910,9 @@ check_format_string(Fmt) ->
     extract_sequences(Fmt, []).
 
 extract_sequences(Fmt, Need0) ->
-    case string:chr(Fmt, $~) of
-        0 -> {ok,lists:reverse(Need0)};         %That's it
-        Pos ->
-            Fmt1 = string:substr(Fmt, Pos+1),   %Skip ~
+    case string:find(Fmt, [$~]) of
+        nomatch -> {ok,lists:reverse(Need0)};         %That's it
+        [$~|Fmt1] ->
             case extract_sequence(1, Fmt1, Need0) of
                 {ok,Need1,Rest} -> extract_sequences(Rest, Need1);
                 Error -> Error
diff --git a/lib/stdlib/src/erl_pp.erl b/lib/stdlib/src/erl_pp.erl
index b0064aadb8..367dbefb82 100644
--- a/lib/stdlib/src/erl_pp.erl
+++ b/lib/stdlib/src/erl_pp.erl
@@ -237,13 +237,20 @@ lform({attribute,Line,Name,Arg}, Opts) ->
 lform({function,Line,Name,Arity,Clauses}, Opts) ->
     lfunction({function,Line,Name,Arity,Clauses}, Opts);
 %% These are specials to make it easier for the compiler.
-lform({error,E}, _Opts) ->
-    leaf(format("~p\n", [{error,E}]));
-lform({warning,W}, _Opts) ->
-    leaf(format("~p\n", [{warning,W}]));
+lform({error,_}=E, Opts) ->
+    message(E, Opts);
+lform({warning,_}=W, Opts) ->
+    message(W, Opts);
 lform({eof,_Line}, _Opts) ->
     $\n.
 
+message(M, #options{encoding = Encoding}) ->
+    F = case Encoding of
+            latin1 -> "~p\n";
+            unicode -> "~tp\n"
+        end,
+    leaf(format(F, [M])).
+
 lattribute({attribute,_Line,type,Type}, Opts) ->
     [typeattr(type, Type, Opts),leaf(".\n")];
 lattribute({attribute,_Line,opaque,Type}, Opts) ->
@@ -902,7 +909,7 @@ maybe_paren(_P, _Prec, Expr) ->
     Expr.
 
 leaf(S) ->
-    {leaf,chars_size(S),S}.
+    {leaf,string:length(S),S}.
 
 %%% Do the formatting. Currently nothing fancy. Could probably have
 %%% done it in one single pass.
@@ -962,7 +969,7 @@ f({seq,Before,After,Sep,LItems}, I0, ST, WT, PP) ->
     Sizes = BSizeL ++ SizeL,
     NSepChars = if
                     is_list(Sep), Sep =/= [] ->
-                        erlang:max(0, length(CharsL)-1);
+                        erlang:max(0, length(CharsL)-1); % not string:length
                     true ->
                         0
                 end,
@@ -1118,7 +1125,7 @@ incr(I, Incr) ->
     I+Incr.
 
 indentation(E, I) when I < 0 ->
-    chars_size(E);
+    string:length(E);
 indentation(E, I0) ->
     I = io_lib_format:indentation(E, I0),
     case has_nl(E) of
@@ -1155,19 +1162,19 @@ write_a_string(S, I, PP) ->
 write_a_string([], _N, _Len, _PP) ->
     [];
 write_a_string(S, N, Len, PP) ->
-    SS = string:sub_string(S, 1, N),
+    SS = string:slice(S, 0, N),
     Sl = write_string(SS, PP),
-    case (chars_size(Sl) > Len) and (N > ?MIN_SUBSTRING) of
+    case (string:length(Sl) > Len) and (N > ?MIN_SUBSTRING) of
         true ->
             write_a_string(S, N-1, Len, PP);
         false ->
             [flat_leaf(Sl) |
-             write_a_string(lists:nthtail(length(SS), S), Len, Len, PP)]
+             write_a_string(string:slice(S, string:length(SS)), Len, Len, PP)]
     end.
 
 flat_leaf(S) ->
     L = lists:flatten(S),
-    {leaf,length(L),L}.
+    {leaf,string:length(L),L}.
 
 write_value(V, PP) ->
     (PP#pp.value_fun)(V).
@@ -1188,15 +1195,6 @@ write_char(C, PP) ->
 a0() ->
     erl_anno:new(0).
 
-chars_size([C | Es]) when is_integer(C) ->
-    1 + chars_size(Es);
-chars_size([E | Es]) ->
-    chars_size(E) + chars_size(Es);
-chars_size([]) ->
-    0;
-chars_size(B) when is_binary(B) ->
-    byte_size(B).
-
 -define(N_SPACES, 30).
 
 spacetab() ->
diff --git a/lib/stdlib/src/erl_scan.erl b/lib/stdlib/src/erl_scan.erl
index 47223b129c..4774c4bf19 100644
--- a/lib/stdlib/src/erl_scan.erl
+++ b/lib/stdlib/src/erl_scan.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2015. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2017. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -752,7 +752,7 @@ scan_string(Cs, St, Line, Col, Toks, {Wcs,Str,Line0,Col0}) ->
         {char_error,Ncs,Error,Nline,Ncol,EndCol} ->
             scan_error(Error, Nline, Ncol, Nline, EndCol, Ncs);
         {error,Nline,Ncol,Nwcs,Ncs} ->
-            Estr = string:substr(Nwcs, 1, 16), % Expanded escape chars.
+            Estr = string:slice(Nwcs, 0, 16), % Expanded escape chars.
             scan_error({string,$\",Estr}, Line0, Col0, Nline, Ncol, Ncs); %"
         {Ncs,Nline,Ncol,Nstr,Nwcs} ->
             Anno = anno(Line0, Col0, St, Nstr),
@@ -767,7 +767,7 @@ scan_qatom(Cs, St, Line, Col, Toks, {Wcs,Str,Line0,Col0}) ->
         {char_error,Ncs,Error,Nline,Ncol,EndCol} ->
             scan_error(Error, Nline, Ncol, Nline, EndCol, Ncs);
         {error,Nline,Ncol,Nwcs,Ncs} ->
-            Estr = string:substr(Nwcs, 1, 16), % Expanded escape chars.
+            Estr = string:slice(Nwcs, 0, 16), % Expanded escape chars.
             scan_error({string,$\',Estr}, Line0, Col0, Nline, Ncol, Ncs); %'
         {Ncs,Nline,Ncol,Nstr,Nwcs} ->
             case catch list_to_atom(Nwcs) of
diff --git a/lib/stdlib/src/escript.erl b/lib/stdlib/src/escript.erl
index 2b9d8ff65b..132f8efbbe 100644
--- a/lib/stdlib/src/escript.erl
+++ b/lib/stdlib/src/escript.erl
@@ -224,8 +224,8 @@ return_sections(S, Bin) ->
 normalize_section(Name, undefined) ->
     {Name, undefined};
 normalize_section(shebang, "#!" ++ Chars) ->
-    Chopped = string:strip(Chars, right, $\n),
-    Stripped = string:strip(Chopped, both),
+    Chopped = string:trim(Chars, trailing, "$\n"),
+    Stripped = string:trim(Chopped, both),
     if
 	Stripped =:= ?SHEBANG ->
 	    {shebang, default};
@@ -233,8 +233,8 @@ normalize_section(shebang, "#!" ++ Chars) ->
 	    {shebang, Stripped}
     end;
 normalize_section(comment, Chars) ->
-    Chopped = string:strip(Chars, right, $\n),
-    Stripped = string:strip(string:strip(Chopped, left, $%), both),
+    Chopped = string:trim(Chars, trailing, "$\n"),
+    Stripped = string:trim(string:trim(Chopped, leading, "$%"), both),
     if
 	Stripped =:= ?COMMENT ->
 	    {comment, default};
@@ -242,8 +242,8 @@ normalize_section(comment, Chars) ->
 	    {comment, Stripped}
     end;
 normalize_section(emu_args, "%%!" ++ Chars) ->
-    Chopped = string:strip(Chars, right, $\n),
-    Stripped = string:strip(Chopped, both),
+    Chopped = string:trim(Chars, trailing, "$\n"),
+    Stripped = string:trim(Chopped, both),
     {emu_args, Stripped};
 normalize_section(Name, Chars) ->
     {Name, Chars}.
diff --git a/lib/stdlib/src/ets.erl b/lib/stdlib/src/ets.erl
index b5d3cd3c8d..4858c8d13c 100644
--- a/lib/stdlib/src/ets.erl
+++ b/lib/stdlib/src/ets.erl
@@ -1717,7 +1717,7 @@ get_line(P, Default) ->
 line_string(Binary) when is_binary(Binary) -> unicode:characters_to_list(Binary);
 line_string(Other) -> Other.
 
-nonl(S) -> string:strip(S, right, $\n).
+nonl(S) -> string:trim(S, trailing, "$\n").
 
 print_number(Tab, Key, Num) ->
     Os = ets:lookup(Tab, Key),
@@ -1746,7 +1746,7 @@ do_display_item(_Height, Width, I, Opos)  ->
     L = to_string(I),
     L2 = if
 	     length(L) > Width - 8 ->
-                 string:substr(L, 1, Width-13) ++ "  ...";
+                 string:slice(L, 0, Width-13) ++ "  ...";
 	     true ->
 		 L
 	 end,
diff --git a/lib/stdlib/src/filename.erl b/lib/stdlib/src/filename.erl
index 9bf4290916..63cfeae57b 100644
--- a/lib/stdlib/src/filename.erl
+++ b/lib/stdlib/src/filename.erl
@@ -1036,10 +1036,10 @@ basedir_linux(Type) ->
         user_log    -> getenv("XDG_CACHE_HOME", ?basedir_linux_user_log,   true);
         site_data   ->
             Base = getenv("XDG_DATA_DIRS",?basedir_linux_site_data,false),
-            string:tokens(Base,":");
+            string:lexemes(Base, ":");
         site_config ->
             Base = getenv("XDG_CONFIG_DIRS",?basedir_linux_site_config,false),
-            string:tokens(Base,":")
+            string:lexemes(Base, ":")
     end.
 
 -define(basedir_darwin_user_data,   "Library/Application Support").
diff --git a/lib/stdlib/src/io_lib_format.erl b/lib/stdlib/src/io_lib_format.erl
index 4b2d15c8b3..e345810ca0 100644
--- a/lib/stdlib/src/io_lib_format.erl
+++ b/lib/stdlib/src/io_lib_format.erl
@@ -380,7 +380,7 @@ float_e(_Fl, {Ds,E}, P) ->
 	{Fs,false} -> [Fs|float_exp(E-1)]
     end.
 
-%% float_man([Digit], Icount, Dcount) -> {[Chars],CarryFlag}.
+%% float_man([Digit], Icount, Dcount) -> {[Char],CarryFlag}.
 %%  Generate the characters in the mantissa from the digits with Icount
 %%  characters before the '.' and Dcount decimals. Handle carry and let
 %%  caller decide what to do at top.
@@ -395,7 +395,7 @@ float_man([D|Ds], I, Dc) ->
 	{Cs,false} -> {[D|Cs],false}
     end;
 float_man([], I, Dc) ->				%Pad with 0's
-    {string:chars($0, I, [$.|string:chars($0, Dc)]),false}.
+    {lists:duplicate(I, $0) ++ [$.|lists:duplicate(Dc, $0)],false}.
 
 float_man([D|_], 0) when D >= $5 -> {[],true};
 float_man([_|_], 0) -> {[],false};
@@ -405,7 +405,7 @@ float_man([D|Ds], Dc) ->
 	{Cs,true} -> {[D+1|Cs],false}; 
 	{Cs,false} -> {[D|Cs],false}
     end;
-float_man([], Dc) -> {string:chars($0, Dc),false}.	%Pad with 0's
+float_man([], Dc) -> {lists:duplicate(Dc, $0),false}.	%Pad with 0's
 
 %% float_exp(Exponent) -> [Char].
 %%  Generate the exponent of a floating point number. Always include sign.
@@ -429,7 +429,7 @@ fwrite_f(Fl, F, Adj, P, Pad) when P >= 1 ->
 float_f(Fl, Fd, P) when Fl < 0.0 ->
     [$-|float_f(-Fl, Fd, P)];
 float_f(Fl, {Ds,E}, P) when E =< 0 ->
-    float_f(Fl, {string:chars($0, -E+1, Ds),1}, P);	%Prepend enough 0's
+    float_f(Fl, {lists:duplicate(-E+1, $0)++Ds,1}, P);	%Prepend enough 0's
 float_f(_Fl, {Ds,E}, P) ->
     case float_man(Ds, E, P) of
 	{Fs,true} -> "1" ++ Fs;			%Handle carry
@@ -751,7 +751,7 @@ adjust(Data, Pad, right) -> [Pad|Data].
 flat_trunc(List, N) when is_integer(N), N >= 0 ->
     string:slice(List, 0, N).
 
-%% A deep version of string:chars/2,3
+%% A deep version of lists:duplicate/2
 
 chars(_C, 0) ->
     [];
diff --git a/lib/stdlib/src/lib.erl b/lib/stdlib/src/lib.erl
index c6eb0d7915..a7980cc294 100644
--- a/lib/stdlib/src/lib.erl
+++ b/lib/stdlib/src/lib.erl
@@ -646,7 +646,7 @@ pp_arguments(PF, As, I, Enc) ->
             Ll = length(L),
             A = list_to_atom(lists:duplicate(Ll, $a)),
             S0 = unicode:characters_to_list(PF([A | T], I+1), Enc),
-            brackets_to_parens([$[,L,string:sub_string(S0, 2+Ll)], Enc);
+            brackets_to_parens([$[,L,string:slice(S0, 1+Ll)], Enc);
         _ -> 
             brackets_to_parens(PF(As, I+1), Enc)
     end.
diff --git a/lib/stdlib/src/otp_internal.erl b/lib/stdlib/src/otp_internal.erl
index c59db903dc..7605ac763d 100644
--- a/lib/stdlib/src/otp_internal.erl
+++ b/lib/stdlib/src/otp_internal.erl
@@ -611,6 +611,52 @@ obsolete_1(filename, find_src, 2) ->
 obsolete_1(erlang, hash, 2) ->
     {removed, {erlang, phash2, 2}, "20.0"};
 
+%% Added in OTP-21
+obsolete_1(string, len, 1) ->
+    {deprecated, "deprecated; use string:length/3 instead"};
+obsolete_1(string, concat, 2) ->
+    {deprecated, "deprecated; use [Str1,Str2] instead"};
+obsolete_1(string, str, 2) ->
+    {deprecated, "deprecated; use string:find/2 instead"};
+obsolete_1(string, rstr, 2) ->
+    {deprecated, "deprecated; use string:find/3 instead"};
+obsolete_1(string, chr, 2) ->
+    {deprecated, "deprecated; use string:find/2 instead"};
+obsolete_1(string, rchr, 2) ->
+    {deprecated, "deprecated; use string:find/3 instead"};
+obsolete_1(string, span, 2) ->
+    {deprecated, "deprecated; use string:take/2 instead"};
+obsolete_1(string, cspan, 2) ->
+    {deprecated, "deprecated; use string:take/3 instead"};
+obsolete_1(string, substr, _) ->
+    {deprecated, "deprecated; use string:slice/3 instead"};
+obsolete_1(string, tokens, 2) ->
+    {deprecated, "deprecated; use string:lexemes/2 instead"};
+obsolete_1(string, chars, _) ->
+    {deprecated, "deprecated; use lists:duplicate/2 instead"};
+obsolete_1(string, copies, _) ->
+    {deprecated, "deprecated; use lists:duplicate/2 instead"};
+obsolete_1(string, words, _) ->
+    {deprecated, "deprecated; use string:lexemes/2 instead"};
+obsolete_1(string, strip, _) ->
+    {deprecated, "deprecated; use string:trim/3 instead"};
+obsolete_1(string, sub_word, _) ->
+    {deprecated, "deprecated; use string:nth_lexeme/3 instead"};
+obsolete_1(string, sub_string, _) ->
+    {deprecated, "deprecated; use string:slice/3 instead"};
+obsolete_1(string, left, _) ->
+    {deprecated, "deprecated; use string:pad/3 instead"};
+obsolete_1(string, right, _) ->
+    {deprecated, "deprecated; use string:pad/3 instead"};
+obsolete_1(string, centre, _) ->
+    {deprecated, "deprecated; use string:pad/3 instead"};
+obsolete_1(string, join, _) ->
+    {deprecated, "deprecated; use lists:join/2 instead"};
+obsolete_1(string, to_upper, _) ->
+    {deprecated, "deprecated; use string:uppercase/1 or string:titlecase/1 instead"};
+obsolete_1(string, to_lower, _) ->
+    {deprecated, "deprecated; use string:lowercase/1 or string:casefold/1 instead"};
+
 %% not obsolete
 
 obsolete_1(_, _, _) ->
diff --git a/lib/stdlib/src/slave.erl b/lib/stdlib/src/slave.erl
index d7cf6386f5..b3f3206d67 100644
--- a/lib/stdlib/src/slave.erl
+++ b/lib/stdlib/src/slave.erl
@@ -320,7 +320,7 @@ mk_cmd(Host, Name, Args, Waiter, Prog0) ->
 %% emulator and flags as the test node. The return from lib:progname()
 %% could then typically be '/<full_path_to>/cerl -gcov').
 quote_progname(Progname) ->
-    do_quote_progname(string:tokens(to_list(Progname)," ")).
+    do_quote_progname(string:lexemes(to_list(Progname)," ")).
 
 do_quote_progname([Prog]) ->
     "\""++Prog++"\"";
diff --git a/lib/stdlib/src/string.erl b/lib/stdlib/src/string.erl
index 4972da297d..5a4d2df2a6 100644
--- a/lib/stdlib/src/string.erl
+++ b/lib/stdlib/src/string.erl
@@ -87,6 +87,16 @@
 %%% May be removed
 -export([list_to_float/1, list_to_integer/1]).
 
+-deprecated([{len,1},{concat,2},
+             {str,2},{chr,2},{rchr,2},{rstr,2},
+             {span,2},{cspan,2},{substr,'_'},{tokens,2},
+             {chars,'_'},
+             {copies,2},{words,'_'},{strip,'_'},
+             {sub_word,'_'},{left,'_'},{right,'_'},
+             {sub_string,'_'},{centre,'_'},{join,2},
+             {to_upper,1}, {to_lower,1}
+            ]).
+
 %% Uses bifs: string:list_to_float/1 and string:list_to_integer/1
 -spec list_to_float(String) -> {Float, Rest} | {'error', Reason} when
       String :: string(),
diff --git a/lib/stdlib/uc_spec/gen_unicode_mod.escript b/lib/stdlib/uc_spec/gen_unicode_mod.escript
index 5b8763f576..674e5a0628 100755
--- a/lib/stdlib/uc_spec/gen_unicode_mod.escript
+++ b/lib/stdlib/uc_spec/gen_unicode_mod.escript
@@ -65,7 +65,7 @@ main(_) ->
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 parse_unicode_data(Line0, Acc) ->
-    Line = string:strip(Line0, right, $\n),
+    Line = string:chomp(Line0),
     [CodePoint,Name,_Cat,Class,_BiDi,Decomp,
      _N1,_N2,_N3,_BDMirror,_Uni1,_Iso|Case] = tokens(Line, ";"),
     {Dec,Comp} = case to_decomp(Decomp) of
@@ -78,14 +78,14 @@ parse_unicode_data(Line0, Acc) ->
      |Acc].
 
 to_class(String) ->
-    list_to_integer(string:strip(String, both)).
+    list_to_integer(string:trim(String, both)).
 
 to_decomp("") -> [];
 to_decomp("<" ++ Str) ->
-    [Tag,Rest]  = string:tokens(Str, ">"),
+    [Tag,Rest]  = string:lexemes(Str, ">"),
     {list_to_atom(Tag), to_decomp(Rest)};
 to_decomp(CodePoints) ->
-    CPL = string:tokens(CodePoints, " "),
+    CPL = string:lexemes(CodePoints, " "),
     [hex_to_int(CP) || CP <- CPL].
 
 to_case(["","",""]) -> [];
@@ -105,20 +105,20 @@ parse_special_casing(Line, Table) ->
     array:set(CP, Entry#cp{cs=Case}, Table).
 
 to_scase([Lower,Title,Upper|_]) ->
-    {unlist([hex_to_int(CP) || CP <- string:strip(string:tokens(Upper, " "), both)]),
-     unlist([hex_to_int(CP) || CP <- string:strip(string:tokens(Lower, " "), both)]),
-     unlist([hex_to_int(CP) || CP <- string:strip(string:tokens(Title, " "), both)]),
+    {unlist([hex_to_int(CP) || CP <- string:lexemes(Upper, " ")]),
+     unlist([hex_to_int(CP) || CP <- string:lexemes(Lower, " ")]),
+     unlist([hex_to_int(CP) || CP <- string:lexemes(Title, " ")]),
      []}.
 
 parse_case_folding(Line, Table) ->
     [CodePoint, Class0, CaseStr |_Comments] = tokens(Line, ";"),
-    Class = string:strip(Class0, both),
+    Class = string:trim(Class0, both),
     if Class =:= "T" -> Table; %% Do not support localization yet
        Class =:= "S" -> Table; %% Ignore simple
        true ->
             CP = hex_to_int(CodePoint),
             Case = unlist([hex_to_int(CPC) ||
-                              CPC <- string:strip(string:tokens(CaseStr, " "), both)]),
+                              CPC <- string:lexemes(CaseStr, " ")]),
             #cp{cs={U,L,T,_}} = Entry = array:get(CP, Table),
             array:set(CP, Entry#cp{cs={U,L,T,Case}}, Table)
     end.
@@ -869,10 +869,10 @@ optimize_ranges_1(Rs) ->
 
 hex_to_int([]) -> [];
 hex_to_int(HexStr) ->
-    list_to_integer(string:strip(HexStr, both), 16).
+    list_to_integer(string:trim(HexStr, both), 16).
 
 to_atom(Str) ->
-    list_to_atom(string:to_lower(string:strip(Str, both))).
+    list_to_atom(string:lowercase(string:trim(Str, both))).
 
 foldl(Fun, Acc, Fd) ->
     Get = fun() -> file:read_line(Fd) end,
@@ -892,7 +892,7 @@ foldl_1(Fun, Acc, Get) ->
 
 
 
-%% Differs from string:tokens, it returns empty string as token between two delimiters
+%% Differs from string:lexemes, it returns empty string as token between two delimiters
 tokens(S, [C]) ->
     tokens(lists:reverse(S), C, []).