gcc/ada/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) 1992-2023, 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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  This package contains low level output routines used by the compiler for
  27 --  writing error messages and informational output. It is also used by the
  28 --  debug source file output routines (see Sprint.Print_Debug_Line).
  29
  30 with Hostparm;
  31 with Types;    use Types;
  32
  33 pragma Warnings (Off);
  34 --  This package is used also by gnatcoll
  35 with System.OS_Lib; use System.OS_Lib;
  36 pragma Warnings (On);
  37
  38 package Output is
  39    pragma Elaborate_Body;
  40
  41    type Output_Proc is access procedure (S : String);
  42    --  This type is used for the Set_Special_Output procedure. If Output_Proc
  43    --  is called, then instead of lines being written to standard error or
  44    --  standard output, a call is made to the given procedure for each line,
  45    --  passing the line with an end of line character (which is a single
  46    --  ASCII.LF character, even in systems which normally use CR/LF or some
  47    --  other sequence for line end).
  48
  49    -----------------
  50    -- Subprograms --
  51    -----------------
  52
  53    procedure Set_Special_Output (P : Output_Proc);
  54    --  Sets subsequent output to call procedure P. If P is null, then the call
  55    --  cancels the effect of a previous call, reverting the output to standard
  56    --  error or standard output depending on the mode at the time of previous
  57    --  call. Any exception generated by calls to P is simply propagated to
  58    --  the caller of the routine causing the write operation.
  59
  60    procedure Cancel_Special_Output;
  61    --  Cancels the effect of a call to Set_Special_Output, if any. The output
  62    --  is then directed to standard error or standard output depending on the
  63    --  last call to Set_Standard_Error or Set_Standard_Output. It is never an
  64    --  error to call Cancel_Special_Output. It has the same effect as calling
  65    --  Set_Special_Output (null).
  66
  67    procedure Ignore_Output (S : String);
  68    --  Does nothing. To disable output, pass Ignore_Output'Access to
  69    --  Set_Special_Output.
  70
  71    procedure Set_Standard_Error;
  72    --  Sets subsequent output to appear on the standard error file (whatever
  73    --  that might mean for the host operating system, if anything) when
  74    --  no special output is in effect. When a special output is in effect,
  75    --  the output will appear on standard error only after special output
  76    --  has been cancelled.
  77
  78    procedure Set_Standard_Output;
  79    --  Sets subsequent output to appear on the standard output file (whatever
  80    --  that might mean for the host operating system, if anything) when no
  81    --  special output is in effect. When a special output is in effect, the
  82    --  output will appear on standard output only after special output has been
  83    --  cancelled. Output to standard output is the default mode before any call
  84    --  to either of the Set procedures.
  85
  86    procedure Set_Output (FD : File_Descriptor);
  87    --  Sets subsequent output to appear on the given file descriptor when no
  88    --  special output is in effect. When a special output is in effect, the
  89    --  output will appear on the given file descriptor only after special
  90    --  output has been cancelled.
  91
  92    procedure Push_Output;
  93    --  Saves the current output destination on a stack, but leaves it
  94    --  unchanged. This subprogram only supports a small stack and is normally
  95    --  used with a depth of one.
  96
  97    procedure Pop_Output;
  98    --  Changes the current output destination to be the last output destination
  99    --  popped using Push_Output.
 100
 101    procedure Indent;
 102    --  Increases the current indentation level. Whenever a line is written
 103    --  (triggered by Eol), an appropriate amount of whitespace is added to the
 104    --  beginning of the line, wrapping around if it gets too long.
 105
 106    procedure Outdent;
 107    --  Decreases the current indentation level
 108
 109    procedure Write_Char (C : Character);
 110    --  Write one character to the standard output file. If the character is LF,
 111    --  this is equivalent to Write_Eol.
 112
 113    procedure Write_Erase_Char (C : Character);
 114    --  If last character in buffer matches C, erase it, otherwise no effect
 115
 116    procedure Write_Eol;
 117    --  Write an end of line (whatever is required by the system in use, e.g.
 118    --  CR/LF for DOS, or LF for Unix) to the standard output file. This routine
 119    --  also empties the line buffer, actually writing it to the file. Note that
 120    --  Write_Eol is the only routine that causes any actual output to be
 121    --  written. Trailing spaces are removed.
 122
 123    procedure Write_Eol_Keep_Blanks;
 124    --  Similar as Write_Eol, except that trailing spaces are not removed
 125
 126    procedure Write_Int (Val : Int);
 127    procedure Write_Int_64 (Val : Int_64);
 128    --  Write an integer value with no leading blanks or zeroes. Negative values
 129    --  are preceded by a minus sign).
 130
 131    procedure Write_Spaces (N : Nat);
 132    --  Write N spaces
 133
 134    procedure Write_Str (S : String);
 135    --  Write a string of characters to the standard output file. Note that
 136    --  end of line is normally handled separately using WRITE_EOL, but it is
 137    --  allowable for the string to contain LF (but not CR) characters, which
 138    --  are properly interpreted as end of line characters. The string may also
 139    --  contain horizontal tab characters.
 140
 141    procedure Write_Line (S : String);
 142    --  Equivalent to Write_Str (S) followed by Write_Eol;
 143
 144    function Last_Char return Character;
 145    --  Returns last character written on the current line, or null if the
 146    --  current line is (so far) empty.
 147
 148    procedure Delete_Last_Char;
 149    --  Deletes last character written on the current line, no effect if the
 150    --  current line is (so far) empty.
 151
 152    function Column return Pos;
 153    pragma Inline (Column);
 154    --  Returns the number of the column about to be written (e.g. a value of 1
 155    --  means the current line is empty).
 156
 157    -------------------------
 158    -- Buffer Save/Restore --
 159    -------------------------
 160
 161    --  This facility allows the current line buffer to be saved and restored
 162
 163    type Saved_Output_Buffer is private;
 164    --  Type used for Save/Restore_Buffer
 165
 166    Buffer_Max : constant := Hostparm.Max_Line_Length;
 167    --  Maximal size of a buffered output line
 168
 169    function Save_Output_Buffer return Saved_Output_Buffer;
 170    --  Save current line buffer and reset line buffer to empty
 171
 172    procedure Restore_Output_Buffer (S : Saved_Output_Buffer);
 173    --  Restore previously saved output buffer. The value in S is not affected
 174    --  so it is legitimate to restore a buffer more than once.
 175
 176    --------------------------
 177    -- Debugging Procedures --
 178    --------------------------
 179
 180    --  The following procedures are intended only for debugging purposes,
 181    --  for temporary insertion into the text in environments where a debugger
 182    --  is not available. They all have non-standard very short lower case
 183    --  names, precisely to make sure that they are only used for debugging.
 184
 185    procedure w (C : Character);
 186    --  Dump quote, character, quote, followed by line return
 187
 188    procedure w (S : String);
 189    --  Dump string followed by line return
 190
 191    procedure w (V : Int);
 192    --  Dump integer followed by line return
 193
 194    procedure w (B : Boolean);
 195    --  Dump Boolean followed by line return
 196
 197    procedure w (L : String; C : Character);
 198    --  Dump contents of string followed by blank, quote, character, quote
 199
 200    procedure w (L : String; S : String);
 201    --  Dump two strings separated by blanks, followed by line return
 202
 203    procedure w (L : String; V : Int);
 204    --  Dump contents of string followed by blank, integer, line return
 205
 206    procedure w (L : String; B : Boolean);
 207    --  Dump contents of string followed by blank, Boolean, line return
 208
 209 private
 210
 211    type Saved_Output_Buffer is record
 212       Buffer          : String (1 .. Buffer_Max + 1);
 213       Next_Col        : Positive;
 214       Cur_Indentation : Natural;
 215    end record;
 216
 217 end Output;