Add some new utility predicates for use with streams.

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Add some new utility predicates for use with streams.

library/stream.m:
	Add the predicate stream.format/5, an analogue of io.format,
	that writes formatted output using an arbitrary string writer.

	Add a predicate stream.ignore_whitespace/4 that can be used
	to skip past whitespace in a putback char reader stream.

library/Mercury.options:
	Don't warn about unknown format calls in the stream module.

	Unrelated change: remove a workaround that was put in place
	before the addition of the `--no-warn-obsolete' option.

compiler/format_call.m:
	Also analyse calls to stream.format/5.

tests/hard_coded/Mmakefile:
tests/hard_coded/stream_format.{m,exp}:
tests/hard_coded/stream_ignore_ws.{m,exp,data}:
	Test stream.format/5 and stream.ignore_whitespace/3.

tests/invalid/string_format_bad.{m,exp}:
tests/invalid/string_format_unknown.{m,exp}:
	Check that we emit messages for bad/unknown calls to stream.format/5.

compiler/format_call.m

@@ -9,11 +9,11 @@
 % File: format_call.m.
 % Author: zs.
 % 
-% The job of this module is to generate warnings about calls to string.format
-% and io.format in which the format string and the supplied lists of values
-% do not agree. The difficult part of this job is actually finding the values
-% of the variables representing the format string and the list of values to
-% be printed.
+% The job of this module is to generate warnings about calls to
+% string.format, io.format and stream.format in which the format string and
+% the supplied lists of values do not agree. The difficult part of this job
+% is actually finding the values of the variables representing the format
+% string and the list of values to be printed.
 %
 % The general approach is a backwards traversal of the procedure body. During
 % this traversal, we assign an id to every conjunction (considering a cond and
@@ -194,6 +194,11 @@ is_format_call(ModuleName, Name, Args, FormatStringVar, FormattedValuesVar) :-
         ( Args = [FormatStringVar, FormattedValuesVar, _IOIn, _IOOut]
         ; Args = [_Stream, FormatStringVar, FormattedValuesVar, _IOIn, _IOOut]
         )
+    ; ModuleName = mercury_std_lib_module_name("stream") ->
+        % Since we do this check after polymorphism there will have been
+        % a typeclassinfo inserted at the front of the argument list.
+        Args = [_TC_InfoForStream, _Stream, FormatStringVar,
+            FormattedValuesVar, _StateIn, _StateOut]
     ;
         fail
     ).

compiler/simplify.m

@@ -2777,7 +2777,8 @@ case_list_contains_trace([Case0 | Cases0], [Case | Cases], !ContainsTrace) :-
                                         % typeclass_infos.
                 format_calls            :: bool,
                                         % Do we have any calls to
-                                        % string.format and io.format?
+                                        % string.format, stream.format and
+                                        % io.format?
                 inside_dupl_for_switch  :: bool,
                                         % Are we currently inside a goal
                                         % that was duplicated for a switch?

library/Mercury.options

@@ -21,8 +21,10 @@ MCFLAGS-std_util += --no-halt-at-warn
 MCFLAGS-dir += --no-halt-at-warn
 MCFLAGS-exception += --no-halt-at-warn
 
-# We need a better way to ignore obsolete procedures.
-MCFLAGS-bintree_set += --no-halt-at-warn
+# Ignore warnings about obsolete procedures from this module since
+# the entire module is obsolete.
+#
+MCFLAGS-bintree_set += --no-warn-obsolete
 
 # io.m uses library features that are supported by POSIX but which are not
 # part of ANSI C, such as `struct stat', fileno(), and putenv().
@@ -33,6 +35,7 @@ MGNUCFLAGS-io =	--no-ansi
 # in terms of io.format/4, and string.format/2 in terms of string.format/3.
 # varset.trans_opt includes the relevant part of string.opt.
 MCFLAGS-io     = --no-warn-unknown-format-calls
+MCFLAGS-stream = --no-warn-unknown-format-calls
 MCFLAGS-string = --no-warn-unknown-format-calls
 
 MCFLAGS-mer_std = --no-warn-nothing-exported

library/stream.m

@@ -20,6 +20,8 @@
 :- interface.
 
 :- import_module bool.
+:- import_module char.
+:- import_module list.
 :- import_module string.
 
 %-----------------------------------------------------------------------------%
@@ -29,6 +31,11 @@
 
 :- type stream.name == string.
 
+:- type stream.result(Error)
+    --->    ok
+    ;       eof
+    ;       error(Error).
+
 :- type stream.result(T, Error)
     --->    ok(T)
     ;       eof
@@ -269,6 +276,22 @@
     in(pred(in, out, in, out, di, uo) is cc_multi), in, out, di, uo)
     is cc_multi.
 
+%-----------------------------------------------------------------------------%
+%
+% Misc. operations on streams
+%
+
+    % A version of io.format that works for arbitrary string writers.
+    %
+:- pred stream.format(Stream::in, string::in, list(poly_type)::in,
+    State::di, State::uo) is det <= stream.writer(Stream, string, State).
+
+    % Discard all the whitespace from the specified stream.
+    %
+:- pred stream.ignore_whitespace(Stream::in, stream.result(Error)::out,
+    State::di, State::uo)
+    is det <= stream.putback(Stream, char, State, Error).
+
 %-----------------------------------------------------------------------------%
 %-----------------------------------------------------------------------------%
 
@@ -347,6 +370,32 @@ stream.input_stream_fold2_state_maybe_stop(Stream, Pred, T0, Res, !S) :-
         Res = error(T0, Error)
     ).
 
+%-----------------------------------------------------------------------------%
+
+stream.format(Stream, FormatString, Arguments, !State) :-
+    string.format(FormatString, Arguments, String),
+    put(Stream, String, !State).
+    
+%-----------------------------------------------------------------------------%
+    
+stream.ignore_whitespace(Stream, Result, !State) :-
+    get(Stream, CharResult, !State),
+    (
+        CharResult = error(Error),
+        Result = error(Error)
+    ;
+        CharResult = eof,
+        Result = eof
+    ;
+        CharResult = ok(Char),
+        ( is_whitespace(Char) ->
+            stream.ignore_whitespace(Stream, Result, !State)
+        ;
+            unget(Stream, Char, !State),
+            Result = ok
+        )
+    ).
+    
 %-----------------------------------------------------------------------------%
 :- end_module stream.
 %-----------------------------------------------------------------------------%

tests/hard_coded/Mmakefile

@@ -185,6 +185,8 @@ ORDINARY_PROGS=	\
 	solver_ite_inits \
 	space \
 	stable_sort \
+	stream_format \
+	stream_ignore_ws \
 	stream_test \
 	string_alignment \
 	string_alignment_bug \
@@ -578,6 +580,9 @@ nonascii_gen:	nonascii_gen.c
 stream_test.out: stream_test
 	./stream_test < stream_test.data > stream_test.out
 
+stream_ignore_ws.out: stream_ignore_ws
+	./stream_ignore_ws < stream_ignore_ws.data > stream_ignore_ws.out
+
 # The trace_goal_env_1 and trace_goal_env_2 test cases differ from each other
 # only in that the latter is executed with the TRACE_ABC environment variable
 # set.

tests/hard_coded/stream_format.exp

@@ -0,0 +1 @@
+foo561a3.141000

tests/hard_coded/stream_format.m

@@ -0,0 +1,17 @@
+:- module stream_format.
+:- interface.
+
+:- import_module io.
+
+:- pred main(io::di, io::uo) is det.
+
+:- implementation.
+
+:- import_module list.
+:- import_module stream.
+:- import_module string.
+
+main(!IO) :-
+     io.stdout_stream(Stdout, !IO),
+     stream.format(Stdout, "%s%d%c%f\n",
+          [s("foo"), i(561), c('a'), f(3.141)], !IO).

tests/hard_coded/stream_ignore_ws.data

@@ -0,0 +1,7 @@
+     
+     			
+
+			       
+
+
+			       foo bar baz

tests/hard_coded/stream_ignore_ws.exp

@@ -0,0 +1 @@
+foo bar baz

tests/hard_coded/stream_ignore_ws.m

@@ -0,0 +1,24 @@
+:- module stream_ignore_ws.
+:- interface.
+
+:- import_module io.
+
+:- pred main(io::di, io::uo) is det.
+
+:- implementation.
+
+:- import_module stream.
+
+main(!IO) :-
+	io.stdin_stream(Stdin, !IO),
+	stream.ignore_whitespace(Stdin, IgnoreResult, !IO),
+	( IgnoreResult = ok ->
+		io.read_file_as_string(Stdin, MaybePartialRes, !IO),
+		( MaybePartialRes = ok(String) ->
+		    io.write_string(String, !IO)
+		;
+		    io.write_string("io.read_file_as_string FAILED\n", !IO)
+		)
+	;
+		io.write_string("stream.ignore_whitespace FAILED\n", !IO)
+	).

tests/invalid/string_format_bad.err_exp

@@ -1,16 +1,19 @@
-string_format_bad.m:020: Mismatched format and values in call to
-string_format_bad.m:020:   `string.format'/3:
-string_format_bad.m:020:   format string invalid.
-string_format_bad.m:022: Mismatched format and values in call to
-string_format_bad.m:022:   `string.format'/3:
-string_format_bad.m:022:   invalid conversion specifier.
-string_format_bad.m:025: Mismatched format and values in call to `io.format'/4:
-string_format_bad.m:025:   invalid conversion specifier.
-string_format_bad.m:026: Mismatched format and values in call to `io.format'/5:
+string_format_bad.m:021: Mismatched format and values in call to
+string_format_bad.m:021:   `string.format'/3:
+string_format_bad.m:021:   format string invalid.
+string_format_bad.m:023: Mismatched format and values in call to
+string_format_bad.m:023:   `string.format'/3:
+string_format_bad.m:023:   invalid conversion specifier.
+string_format_bad.m:026: Mismatched format and values in call to `io.format'/4:
 string_format_bad.m:026:   invalid conversion specifier.
-string_format_bad.m:027: Mismatched format and values in call to `io.format'/4:
+string_format_bad.m:027: Mismatched format and values in call to `io.format'/5:
 string_format_bad.m:027:   invalid conversion specifier.
-string_format_bad.m:036: Mismatched format and values in call to `io.format'/5:
-string_format_bad.m:036:   invalid conversion specifier.
-string_format_bad.m:041: Mismatched format and values in call to `io.format'/5:
-string_format_bad.m:041:   invalid conversion specifier.
+string_format_bad.m:028: Mismatched format and values in call to
+string_format_bad.m:028:   `stream.format'/5:
+string_format_bad.m:028:   invalid conversion specifier.
+string_format_bad.m:029: Mismatched format and values in call to `io.format'/4:
+string_format_bad.m:029:   invalid conversion specifier.
+string_format_bad.m:038: Mismatched format and values in call to `io.format'/5:
+string_format_bad.m:038:   invalid conversion specifier.
+string_format_bad.m:043: Mismatched format and values in call to `io.format'/5:
+string_format_bad.m:043:   invalid conversion specifier.

tests/invalid/string_format_bad.m

@@ -14,6 +14,7 @@
 :- import_module float.
 :- import_module int.
 :- import_module list.
+:- import_module stream.
 :- import_module string.
 
 main(!IO) :-
@@ -24,6 +25,7 @@ main(!IO) :-
     io.stdout_stream(OutputStream, !IO),
     io.format("%d", [s("x3")], !IO),
     io.format(OutputStream, "%d", [s("x4")], !IO),
+    stream.format(OutputStream, "%d", [s("x4")], !IO),
     io.format("%w", [i(5)], !IO),
     io.write_string(p(s("five")), !IO),
     F6 = "%s %f",

tests/invalid/string_format_unknown.err_exp

@@ -1,18 +1,20 @@
-string_format_unknown.m:021: Unknown format string in call to
-string_format_unknown.m:021:   `string.format'/3.
-string_format_unknown.m:023: Mismatched format and values in call to
-string_format_unknown.m:023:   `string.format'/3:
-string_format_unknown.m:023:   invalid conversion specifier.
-string_format_unknown.m:026: Mismatched format and values in call to
-string_format_unknown.m:026:   `io.format'/4:
-string_format_unknown.m:026:   invalid conversion specifier.
+string_format_unknown.m:022: Unknown format string in call to
+string_format_unknown.m:022:   `string.format'/3.
+string_format_unknown.m:024: Mismatched format and values in call to
+string_format_unknown.m:024:   `string.format'/3:
+string_format_unknown.m:024:   invalid conversion specifier.
 string_format_unknown.m:027: Mismatched format and values in call to
-string_format_unknown.m:027:   `io.format'/5:
+string_format_unknown.m:027:   `io.format'/4:
 string_format_unknown.m:027:   invalid conversion specifier.
 string_format_unknown.m:028: Mismatched format and values in call to
-string_format_unknown.m:028:   `io.format'/4:
+string_format_unknown.m:028:   `io.format'/5:
 string_format_unknown.m:028:   invalid conversion specifier.
-string_format_unknown.m:038: Unknown format values in call to `io.format'/5.
-string_format_unknown.m:043: Mismatched format and values in call to
-string_format_unknown.m:043:   `io.format'/5:
-string_format_unknown.m:043:   invalid conversion specifier.
+string_format_unknown.m:029: Mismatched format and values in call to
+string_format_unknown.m:029:   `io.format'/4:
+string_format_unknown.m:029:   invalid conversion specifier.
+string_format_unknown.m:039: Unknown format values in call to `io.format'/5.
+string_format_unknown.m:040: Unknown format values in call to
+string_format_unknown.m:040:   `stream.format'/5.
+string_format_unknown.m:045: Mismatched format and values in call to
+string_format_unknown.m:045:   `io.format'/5:
+string_format_unknown.m:045:   invalid conversion specifier.

tests/invalid/string_format_unknown.m

@@ -14,6 +14,7 @@
 :- import_module float.
 :- import_module int.
 :- import_module list.
+:- import_module stream.
 :- import_module string.
 
 main(!IO) :-
@@ -36,6 +37,7 @@ main(!IO) :-
         V6 = [s("six"), V6A],
         copy(V6, C6),
         io.format(OutputStream, F6, C6, !IO),
+        stream.format(OutputStream, F6, C6, !IO),
         make_bool(7, T7),
         F7 = "%d %s %d",
         (