gcc/ada/gnatprep.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             G N A T P R E P                              --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2005, 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 2,  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 COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 --  This program provides a simple preprocessing capability for Ada programs.
  28 --  It is designed for use with GNAT, but is not dependent on any special
  29 --  features of GNAT.
  30
  31 --    To call gnatprep use
  32
  33 --      gnatprep infile outfile [deffile] [-v] [-c] [-b] [-r] [-s] [-u]
  34 --            [-Dsymbol=value]
  35
  36 --    where
  37
  38 --      infile is the full name of the input file, which is an Ada source
  39 --      file containing preprocessor directives.
  40
  41 --      outfile is the full name of the output file, which is an Ada source
  42 --      in standard Ada form. When used with GNAT, this file name will
  43 --      normally have an ads or adb suffix.
  44
  45 --      deffile is the full name of a text file containing definitions of
  46 --      symbols to be referenced by the preprocessor. This argument is
  47 --      optional.
  48
  49 --      The -c switch, causes both preprocessor lines and the lines deleted
  50 --      by preprocessing to be retained in the output source as comments marked
  51 --      with the special string "--! ". This option will result in line numbers
  52 --      being preserved in the output file.
  53
  54 --      The -b switch causes both preprocessor lines and the lines deleted by
  55 --      preprocessing to be replaced by blank lines in the output source file,
  56 --      thus preserving line numbers in the output file.
  57
  58 --      The -r switch causes a Source_Reference pragma to be generated that
  59 --      references the original input file, so that error messages will use
  60 --      the file name of this original file.
  61
  62 --      The -u switch causes gnatprep to treat any undefined symbol that it
  63 --      encounters as having the value False. Otherwise an undefined symbol
  64 --      is a fatal error.
  65
  66 --      The -s switch causes a sorted list of symbol names and values to be
  67 --      listed on the standard output file.
  68
  69 --      The -v switch causes a Copyright notice to be displayed, and
  70 --      lines containing errors in the input file or the definition file
  71 --      to be displayed before the errors.
  72
  73 --      The -D switch causes symbol 'symbol' to be associated with 'value'.
  74 --      This symbols can then be referenced by the preprocessor. Several
  75 --      -D switches may be specified.
  76
  77 --      Note: if neither -b nor -c is present, then preprocessor lines and
  78 --      deleted lines are completely removed from the output, unless -r is
  79 --      specified, in which case -b is assumed.
  80
  81 --   The definitions file contains lines of the form
  82
  83 --      symbol := value
  84
  85 --   where symbol is an identifier, following normal Ada (case-insensitive)
  86 --   rules for its syntax, and value is one of the following:
  87
  88 --      Empty, corresponding to a null substitution
  89
  90 --      A string literal using normal Ada syntax
  91
  92 --      Any sequence of characters from the set
  93 --        (letters, digits, period, underline)
  94
  95 --   Comment lines may also appear in the definitions file, starting with
  96 --   the usual --, and comments may be added to the definitions lines.
  97
  98 --   The input text may contain preprocessor conditional inclusion lines,
  99 --   and also general symbol substitution sequences.
 100
 101 --   The preprocessor conditional inclusion commands have the form
 102
 103 --      #if <expression> [then]
 104 --         lines
 105 --      #elsif <expression> [then]
 106 --         lines
 107 --      #elsif <expression> [then]
 108 --         lines
 109 --      ...
 110 --      #else
 111 --         lines
 112 --      #end if;
 113 --
 114 --     Where expression is defined by the following grammar :
 115 --        expression ::=  <symbol>
 116 --        expression ::=  <symbol> = "<value>"
 117 --        expression ::=  <symbol> = <symbol>
 118 --        expression ::=  <symbol> 'Defined
 119 --        expression ::=  not <expression>
 120 --        expression ::=  <expression> and <expression>
 121 --        expression ::=  <expression> or <expression>
 122 --        expression ::=  <expression> and then <expression>
 123 --        expression ::=  <expression> or else <expression>
 124 --        expression ::=  ( <expression> )
 125
 126 --        "or" and "and" may not be used in the same expression without
 127 --        using parentheses.
 128
 129 --     For these Boolean tests, the symbol must have either the value True or
 130 --     False. If the value is True, then the corresponding lines are included,
 131 --     and if the value is False, they are excluded. It is an error to
 132 --     reference a symbol not defined in the symbol definitions file, or
 133 --     to reference a symbol that has a value other than True or False.
 134
 135 --     The use of the not operator inverts the sense of this logical test, so
 136 --     that the lines are included only if the symbol is not defined.
 137
 138 --     The THEN keyword is optional as shown
 139
 140 --     Spaces or tabs may appear between the # and the keyword. The keywords
 141 --     and the symbols are case insensitive as in normal Ada code. Comments
 142 --     may be used on a preprocessor line, but other than that, no other
 143 --     tokens may appear on a preprocessor line.
 144
 145 --     Any number of #elsif clauses can be present, including none at all
 146
 147 --     The #else is optional, as in Ada
 148
 149 --     The # marking the start of a preprocessor line must be the first
 150 --     non-blank character on the line, i.e. it must be preceded only by
 151 --     spaces or horizontal tabs.
 152
 153 --   Symbol substitution is obtained by using the sequence
 154
 155 --     $symbol
 156
 157 --   anywhere within a source line, except in a comment. The identifier
 158 --   following the $ must match one of the symbols defined in the symbol
 159 --   definition file, and the result is to substitute the value of the
 160 --   symbol in place of $symbol in the output file.
 161
 162 procedure GNATprep;