File : output.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- O U T P U T --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1992-2015, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
26 -- --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- This package contains low level output routines used by the compiler for
33 -- writing error messages and informational output. It is also used by the
34 -- debug source file output routines (see Sprint.Print_Debug_Line).
35
36 with Hostparm; use Hostparm;
37 with Types; use Types;
38
39 pragma Warnings (Off);
40 -- This package is used also by gnatcoll
41 with System.OS_Lib; use System.OS_Lib;
42 pragma Warnings (On);
43
44 package Output is
45 pragma Elaborate_Body;
46
47 type Output_Proc is access procedure (S : String);
48 -- This type is used for the Set_Special_Output procedure. If Output_Proc
49 -- is called, then instead of lines being written to standard error or
50 -- standard output, a call is made to the given procedure for each line,
51 -- passing the line with an end of line character (which is a single
52 -- ASCII.LF character, even in systems which normally use CR/LF or some
53 -- other sequence for line end).
54
55 -----------------
56 -- Subprograms --
57 -----------------
58
59 procedure Set_Special_Output (P : Output_Proc);
60 -- Sets subsequent output to call procedure P. If P is null, then the call
61 -- cancels the effect of a previous call, reverting the output to standard
62 -- error or standard output depending on the mode at the time of previous
63 -- call. Any exception generated by calls to P is simply propagated to
64 -- the caller of the routine causing the write operation.
65
66 procedure Cancel_Special_Output;
67 -- Cancels the effect of a call to Set_Special_Output, if any. The output
68 -- is then directed to standard error or standard output depending on the
69 -- last call to Set_Standard_Error or Set_Standard_Output. It is never an
70 -- error to call Cancel_Special_Output. It has the same effect as calling
71 -- Set_Special_Output (null).
72
73 procedure Ignore_Output (S : String);
74 -- Does nothing. To disable output, pass Ignore_Output'Access to
75 -- Set_Special_Output.
76
77 procedure Set_Standard_Error;
78 -- Sets subsequent output to appear on the standard error file (whatever
79 -- that might mean for the host operating system, if anything) when
80 -- no special output is in effect. When a special output is in effect,
81 -- the output will appear on standard error only after special output
82 -- has been cancelled.
83
84 procedure Set_Standard_Output;
85 -- Sets subsequent output to appear on the standard output file (whatever
86 -- that might mean for the host operating system, if anything) when no
87 -- special output is in effect. When a special output is in effect, the
88 -- output will appear on standard output only after special output has been
89 -- cancelled. Output to standard output is the default mode before any call
90 -- to either of the Set procedures.
91
92 procedure Set_Output (FD : File_Descriptor);
93 -- Sets subsequent output to appear on the given file descriptor when no
94 -- special output is in effect. When a special output is in effect, the
95 -- output will appear on the given file descriptor only after special
96 -- output has been cancelled.
97
98 procedure Indent;
99 -- Increases the current indentation level. Whenever a line is written
100 -- (triggered by Eol), an appropriate amount of whitespace is added to the
101 -- beginning of the line, wrapping around if it gets too long.
102
103 procedure Outdent;
104 -- Decreases the current indentation level
105
106 procedure Write_Char (C : Character);
107 -- Write one character to the standard output file. If the character is LF,
108 -- this is equivalent to Write_Eol.
109
110 procedure Write_Erase_Char (C : Character);
111 -- If last character in buffer matches C, erase it, otherwise no effect
112
113 procedure Write_Eol;
114 -- Write an end of line (whatever is required by the system in use, e.g.
115 -- CR/LF for DOS, or LF for Unix) to the standard output file. This routine
116 -- also empties the line buffer, actually writing it to the file. Note that
117 -- Write_Eol is the only routine that causes any actual output to be
118 -- written. Trailing spaces are removed.
119
120 procedure Write_Eol_Keep_Blanks;
121 -- Similar as Write_Eol, except that trailing spaces are not removed
122
123 procedure Write_Int (Val : Int);
124 -- Write an integer value with no leading blanks or zeroes. Negative values
125 -- are preceded by a minus sign).
126
127 procedure Write_Spaces (N : Nat);
128 -- Write N spaces
129
130 procedure Write_Str (S : String);
131 -- Write a string of characters to the standard output file. Note that
132 -- end of line is normally handled separately using WRITE_EOL, but it is
133 -- allowable for the string to contain LF (but not CR) characters, which
134 -- are properly interpreted as end of line characters. The string may also
135 -- contain horizontal tab characters.
136
137 procedure Write_Line (S : String);
138 -- Equivalent to Write_Str (S) followed by Write_Eol;
139
140 function Last_Char return Character;
141 -- Returns last character written on the current line, or null if the
142 -- current line is (so far) empty.
143
144 procedure Delete_Last_Char;
145 -- Deletes last character written on the current line, no effect if the
146 -- current line is (so far) empty.
147
148 function Column return Pos;
149 pragma Inline (Column);
150 -- Returns the number of the column about to be written (e.g. a value of 1
151 -- means the current line is empty).
152
153 -------------------------
154 -- Buffer Save/Restore --
155 -------------------------
156
157 -- This facility allows the current line buffer to be saved and restored
158
159 type Saved_Output_Buffer is private;
160 -- Type used for Save/Restore_Buffer
161
162 Buffer_Max : constant := Hostparm.Max_Line_Length;
163 -- Maximal size of a buffered output line
164
165 function Save_Output_Buffer return Saved_Output_Buffer;
166 -- Save current line buffer and reset line buffer to empty
167
168 procedure Restore_Output_Buffer (S : Saved_Output_Buffer);
169 -- Restore previously saved output buffer. The value in S is not affected
170 -- so it is legitimate to restore a buffer more than once.
171
172 --------------------------
173 -- Debugging Procedures --
174 --------------------------
175
176 -- The following procedures are intended only for debugging purposes,
177 -- for temporary insertion into the text in environments where a debugger
178 -- is not available. They all have non-standard very short lower case
179 -- names, precisely to make sure that they are only used for debugging.
180
181 procedure w (C : Character);
182 -- Dump quote, character, quote, followed by line return
183
184 procedure w (S : String);
185 -- Dump string followed by line return
186
187 procedure w (V : Int);
188 -- Dump integer followed by line return
189
190 procedure w (B : Boolean);
191 -- Dump Boolean followed by line return
192
193 procedure w (L : String; C : Character);
194 -- Dump contents of string followed by blank, quote, character, quote
195
196 procedure w (L : String; S : String);
197 -- Dump two strings separated by blanks, followed by line return
198
199 procedure w (L : String; V : Int);
200 -- Dump contents of string followed by blank, integer, line return
201
202 procedure w (L : String; B : Boolean);
203 -- Dump contents of string followed by blank, Boolean, line return
204
205 private
206
207 type Saved_Output_Buffer is record
208 Buffer : String (1 .. Buffer_Max + 1);
209 Next_Col : Positive;
210 Cur_Indentation : Natural;
211 end record;
212
213 end Output;