1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                               S T Y L E G                                --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 1992-2014, 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 version of the Style package implements the standard GNAT style
27--  checking rules. For documentation of these rules, see comments on the
28--  individual procedures.
29
30with Atree;    use Atree;
31with Casing;   use Casing;
32with Csets;    use Csets;
33with Einfo;    use Einfo;
34with Err_Vars; use Err_Vars;
35with Opt;      use Opt;
36with Scans;    use Scans;
37with Sinfo;    use Sinfo;
38with Sinput;   use Sinput;
39with Stylesw;  use Stylesw;
40
41package body Styleg is
42
43   use ASCII;
44
45   Blank_Lines : Nat := 0;
46   --  Counts number of empty lines seen. Reset to zero if a non-empty line
47   --  is encountered. Used to check for trailing blank lines in Check_EOF,
48   --  and for multiple blank lines.
49
50   Blank_Line_Location : Source_Ptr;
51   --  Remembers location of first blank line in a series. Used to issue an
52   --  appropriate diagnostic if subsequent blank lines or the end of file
53   --  is encountered.
54
55   -----------------------
56   -- Local Subprograms --
57   -----------------------
58
59   procedure Check_No_Space_After;
60   --  Checks that there is a non-white space character after the current
61   --  token, or white space followed by a comment, or the end of line.
62   --  Issue error message if not.
63
64   procedure Check_No_Space_Before;
65   --  Check that token is first token on line, or else is not preceded
66   --  by white space. Signal error of space not allowed if not.
67
68   procedure Check_Separate_Stmt_Lines_Cont;
69   --  Non-inlined continuation of Check_Separate_Stmt_Lines
70
71   function Determine_Token_Casing return Casing_Type;
72   --  Determine casing of current token
73
74   procedure Error_Space_Not_Allowed (S : Source_Ptr);
75   --  Posts an error message indicating that a space is not allowed
76   --  at the given source location.
77
78   procedure Error_Space_Required (S : Source_Ptr);
79   --  Posts an error message indicating that a space is required at
80   --  the given source location.
81
82   function Is_White_Space (C : Character) return Boolean;
83   pragma Inline (Is_White_Space);
84   --  Returns True for space or HT, False otherwise
85   --  What about VT and FF, should they return True ???
86
87   procedure Require_Following_Space;
88   pragma Inline (Require_Following_Space);
89   --  Require token to be followed by white space. Used only if in GNAT
90   --  style checking mode.
91
92   procedure Require_Preceding_Space;
93   pragma Inline (Require_Preceding_Space);
94   --  Require token to be preceded by white space. Used only if in GNAT
95   --  style checking mode.
96
97   ----------------------
98   -- Check_Abs_Or_Not --
99   ----------------------
100
101   --  In check token mode (-gnatyt), ABS/NOT must be followed by a space
102
103   procedure Check_Abs_Not is
104   begin
105      if Style_Check_Tokens then
106         if Source (Scan_Ptr) > ' ' then -- ???
107            Error_Space_Required (Scan_Ptr);
108         end if;
109      end if;
110   end Check_Abs_Not;
111
112   ----------------------
113   -- Check_Apostrophe --
114   ----------------------
115
116   --  Do not allow space before or after apostrophe -- OR AFTER???
117
118   procedure Check_Apostrophe is
119   begin
120      if Style_Check_Tokens then
121         Check_No_Space_After;
122      end if;
123   end Check_Apostrophe;
124
125   -----------------
126   -- Check_Arrow --
127   -----------------
128
129   --  In check tokens mode (-gnatys), arrow must be surrounded by spaces,
130   --  except that within the argument of a Depends macro the required format
131   --  is =>+ rather than => +).
132
133   procedure Check_Arrow (Inside_Depends : Boolean := False) is
134   begin
135      if Style_Check_Tokens then
136         Require_Preceding_Space;
137
138         if not Inside_Depends then
139            Require_Following_Space;
140
141         --  Special handling for Inside_Depends
142
143         else
144            if Source (Scan_Ptr) = ' '
145              and then Source (Scan_Ptr + 1) = '+'
146            then
147               Error_Space_Not_Allowed (Scan_Ptr);
148
149            elsif Source (Scan_Ptr) /= ' '
150              and then Source (Scan_Ptr) /= '+'
151            then
152               Require_Following_Space;
153            end if;
154         end if;
155      end if;
156   end Check_Arrow;
157
158   --------------------------
159   -- Check_Attribute_Name --
160   --------------------------
161
162   --  In check attribute casing mode (-gnatya), attribute names must be
163   --  mixed case, i.e. start with an upper case letter, and otherwise
164   --  lower case, except after an underline character.
165
166   procedure Check_Attribute_Name (Reserved : Boolean) is
167      pragma Warnings (Off, Reserved);
168   begin
169      if Style_Check_Attribute_Casing then
170         if Determine_Token_Casing /= Mixed_Case then
171            Error_Msg_SC -- CODEFIX
172              ("(style) bad capitalization, mixed case required");
173         end if;
174      end if;
175   end Check_Attribute_Name;
176
177   ---------------------------
178   -- Check_Binary_Operator --
179   ---------------------------
180
181   --  In check token mode (-gnatyt), binary operators other than the special
182   --  case of exponentiation require surrounding space characters.
183
184   procedure Check_Binary_Operator is
185   begin
186      if Style_Check_Tokens then
187         Require_Preceding_Space;
188         Require_Following_Space;
189      end if;
190   end Check_Binary_Operator;
191
192   ----------------------------
193   -- Check_Boolean_Operator --
194   ----------------------------
195
196   procedure Check_Boolean_Operator (Node : Node_Id) is
197
198      function OK_Boolean_Operand (N : Node_Id) return Boolean;
199      --  Returns True for simple variable, or "not X1" or "X1 and X2" or
200      --  "X1 or X2" where X1, X2 are recursively OK_Boolean_Operand's.
201
202      ------------------------
203      -- OK_Boolean_Operand --
204      ------------------------
205
206      function OK_Boolean_Operand (N : Node_Id) return Boolean is
207      begin
208         if Nkind_In (N, N_Identifier, N_Expanded_Name) then
209            return True;
210
211         elsif Nkind (N) = N_Op_Not then
212            return OK_Boolean_Operand (Original_Node (Right_Opnd (N)));
213
214         elsif Nkind_In (N, N_Op_And, N_Op_Or) then
215            return OK_Boolean_Operand (Original_Node (Left_Opnd (N)))
216                     and then
217                   OK_Boolean_Operand (Original_Node (Right_Opnd (N)));
218
219         else
220            return False;
221         end if;
222      end OK_Boolean_Operand;
223
224   --  Start of processing for Check_Boolean_Operator
225
226   begin
227      if Style_Check_Boolean_And_Or
228        and then Comes_From_Source (Node)
229      then
230         declare
231            Orig : constant Node_Id := Original_Node (Node);
232
233         begin
234            if Nkind_In (Orig, N_Op_And, N_Op_Or) then
235               declare
236                  L : constant Node_Id := Original_Node (Left_Opnd  (Orig));
237                  R : constant Node_Id := Original_Node (Right_Opnd (Orig));
238
239               begin
240                  --  First OK case, simple boolean constants/identifiers
241
242                  if OK_Boolean_Operand (L)
243                       and then
244                     OK_Boolean_Operand (R)
245                  then
246                     return;
247
248                  --  Second OK case, modular types
249
250                  elsif Is_Modular_Integer_Type (Etype (Node)) then
251                     return;
252
253                  --  Third OK case, array types
254
255                  elsif Is_Array_Type (Etype (Node)) then
256                     return;
257
258                  --  Otherwise we have an error
259
260                  elsif Nkind (Orig) = N_Op_And then
261                     Error_Msg -- CODEFIX
262                       ("(style) `AND THEN` required", Sloc (Orig));
263                  else
264                     Error_Msg -- CODEFIX
265                       ("(style) `OR ELSE` required", Sloc (Orig));
266                  end if;
267               end;
268            end if;
269         end;
270      end if;
271   end Check_Boolean_Operator;
272
273   ---------------
274   -- Check_Box --
275   ---------------
276
277   --  In check token mode (-gnatyt), box must be preceded by a space or by
278   --  a left parenthesis. Spacing checking on the surrounding tokens takes
279   --  care of the remaining checks.
280
281   procedure Check_Box is
282   begin
283      if Style_Check_Tokens then
284         if Prev_Token /= Tok_Left_Paren then
285            Require_Preceding_Space;
286         end if;
287      end if;
288   end Check_Box;
289
290   -----------------
291   -- Check_Colon --
292   -----------------
293
294   --  In check token mode (-gnatyt), colon must be surrounded by spaces
295
296   procedure Check_Colon is
297   begin
298      if Style_Check_Tokens then
299         Require_Preceding_Space;
300         Require_Following_Space;
301      end if;
302   end Check_Colon;
303
304   -----------------------
305   -- Check_Colon_Equal --
306   -----------------------
307
308   --  In check token mode (-gnatyt), := must be surrounded by spaces
309
310   procedure Check_Colon_Equal is
311   begin
312      if Style_Check_Tokens then
313         Require_Preceding_Space;
314         Require_Following_Space;
315      end if;
316   end Check_Colon_Equal;
317
318   -----------------
319   -- Check_Comma --
320   -----------------
321
322   --  In check token mode (-gnatyt), comma must be either the first
323   --  token on a line, or be preceded by a non-blank character.
324   --  It must also always be followed by a blank.
325
326   procedure Check_Comma is
327   begin
328      if Style_Check_Tokens then
329         Check_No_Space_Before;
330
331         if Source (Scan_Ptr) > ' ' then
332            Error_Space_Required (Scan_Ptr);
333         end if;
334      end if;
335   end Check_Comma;
336
337   -------------------
338   -- Check_Comment --
339   -------------------
340
341   --  In check comment mode (-gnatyc) there are several requirements on the
342   --  format of comments. The following are permissible comment formats:
343
344   --    1. Any comment that is not at the start of a line, i.e. where the
345   --       initial minuses are not the first non-blank characters on the
346   --       line must have at least one blank after the second minus or a
347   --       special character as defined in rule 5.
348
349   --    2. A row of all minuses of any length is permitted (see procedure
350   --       box above in the source of this routine).
351
352   --    3. A comment line starting with two minuses and a space, and ending
353   --       with a space and two minuses. Again see the procedure title box
354   --       immediately above in the source.
355
356   --    4. A full line comment where two spaces follow the two minus signs.
357   --       This is the normal comment format in GNAT style, as typified by
358   --       the comments you are reading now.
359
360   --    5. A full line comment where the first character after the second
361   --       minus is a special character, i.e. a character in the ASCII
362   --       range 16#21#..16#2F# or 16#3A#..16#3F#. This allows special
363   --       comments, such as those generated by gnatprep, or those that
364   --       appear in the SPARK annotation language to be accepted.
365
366   --       Note: for GNAT internal files (-gnatg switch set on for the
367   --       compilation), the only special sequence recognized and allowed
368   --       is --! as generated by gnatprep.
369
370   --    6. In addition, the comment must be properly indented if comment
371   --       indentation checking is active (Style_Check_Indentation non-zero).
372   --       Either the start column must be a multiple of this indentation,
373   --       or the indentation must match that of the next non-blank line,
374   --       or must match the indentation of the immediately preciding line
375   --       if it is non-blank.
376
377   procedure Check_Comment is
378      S : Source_Ptr;
379      C : Character;
380
381      function Is_Box_Comment return Boolean;
382      --  Returns True if the last two characters on the line are -- which
383      --  characterizes a box comment (as for example follows this spec).
384
385      function Is_Special_Character (C : Character) return Boolean;
386      --  Determines if C is a special character (see rule 5 above)
387
388      function Same_Column_As_Next_Non_Blank_Line return Boolean;
389      --  Called for a full line comment. If the indentation of this comment
390      --  matches that of the next non-blank line in the source, then True is
391      --  returned, otherwise False.
392
393      function Same_Column_As_Previous_Line return Boolean;
394      --  Called for a full line comment. If the previous line is blank, then
395      --  returns False. Otherwise, if the indentation of this comment matches
396      --  that of the previous line in the source, then True is returned,
397      --  otherwise False.
398
399      --------------------
400      -- Is_Box_Comment --
401      --------------------
402
403      function Is_Box_Comment return Boolean is
404         S : Source_Ptr;
405
406      begin
407         --  Do we need to worry about UTF_32 line terminators here ???
408
409         S := Scan_Ptr + 3;
410         while Source (S) not in Line_Terminator loop
411            S := S + 1;
412         end loop;
413
414         return Source (S - 1) = '-' and then Source (S - 2) = '-';
415      end Is_Box_Comment;
416
417      --------------------------
418      -- Is_Special_Character --
419      --------------------------
420
421      function Is_Special_Character (C : Character) return Boolean is
422      begin
423         if GNAT_Mode then
424            return C = '!';
425         else
426            return
427              Character'Pos (C) in 16#21# .. 16#2F#
428                or else
429              Character'Pos (C) in 16#3A# .. 16#3F#;
430         end if;
431      end Is_Special_Character;
432
433      ----------------------------------------
434      -- Same_Column_As_Next_Non_Blank_Line --
435      ----------------------------------------
436
437      function Same_Column_As_Next_Non_Blank_Line return Boolean is
438         P : Source_Ptr;
439
440      begin
441         --  Step to end of line
442
443         P := Scan_Ptr + 2;
444         while Source (P) not in Line_Terminator loop
445            P := P + 1;
446         end loop;
447
448         --  Step past blanks, and line terminators (UTF_32 case???)
449
450         while Source (P) <= ' ' and then Source (P) /= EOF loop
451            P := P + 1;
452         end loop;
453
454         --  Compare columns
455
456         return Get_Column_Number (Scan_Ptr) = Get_Column_Number (P);
457      end Same_Column_As_Next_Non_Blank_Line;
458
459      ----------------------------------
460      -- Same_Column_As_Previous_Line --
461      ----------------------------------
462
463      function Same_Column_As_Previous_Line return Boolean is
464         S, P : Source_Ptr;
465
466      begin
467         --  Point S to start of this line, and P to start of previous line
468
469         S := Line_Start (Scan_Ptr);
470         P := S;
471         Backup_Line (P);
472
473         --  Step P to first non-blank character on line
474
475         loop
476            --  If we get back to start of current line, then the previous line
477            --  was blank, and we always return False in that situation.
478
479            if P = S then
480               return False;
481            end if;
482
483            exit when Source (P) /= ' ' and then Source (P) /= ASCII.HT;
484            P := P + 1;
485         end loop;
486
487         --  Compare columns
488
489         return Get_Column_Number (Scan_Ptr) = Get_Column_Number (P);
490      end Same_Column_As_Previous_Line;
491
492   --  Start of processing for Check_Comment
493
494   begin
495      --  Can never have a non-blank character preceding the first minus
496
497      if Style_Check_Comments then
498         if Scan_Ptr > Source_First (Current_Source_File)
499           and then Source (Scan_Ptr - 1) > ' '
500         then
501            Error_Msg_S -- CODEFIX
502              ("(style) space required");
503         end if;
504      end if;
505
506      --  For a comment that is not at the start of the line, the only
507      --  requirement is that we cannot have a non-blank character after
508      --  the second minus sign or a special character.
509
510      if Scan_Ptr /= First_Non_Blank_Location then
511         if Style_Check_Comments then
512            if Source (Scan_Ptr + 2) > ' '
513              and then not Is_Special_Character (Source (Scan_Ptr + 2))
514            then
515               Error_Msg -- CODEFIX
516                 ("(style) space required", Scan_Ptr + 2);
517            end if;
518         end if;
519
520         return;
521
522      --  Case of a comment that is at the start of a line
523
524      else
525         --  First check, must be in appropriately indented column
526
527         if Style_Check_Indentation /= 0 then
528            if Start_Column rem Style_Check_Indentation /= 0 then
529               if not Same_Column_As_Next_Non_Blank_Line
530                 and then not Same_Column_As_Previous_Line
531               then
532                  Error_Msg_S -- CODEFIX
533                    ("(style) bad column");
534               end if;
535
536               return;
537            end if;
538         end if;
539
540         --  If we are not checking comments, nothing more to do
541
542         if not Style_Check_Comments then
543            return;
544         end if;
545
546         --  Case of not followed by a blank. Usually wrong, but there are
547         --  some exceptions that we permit.
548
549         if Source (Scan_Ptr + 2) /= ' ' then
550            C := Source (Scan_Ptr + 2);
551
552            --  Case of -- all on its own on a line is OK
553
554            if C < ' ' then
555               return;
556            end if;
557
558            --  Case of --x, x special character is OK (gnatprep/SPARK/etc.)
559            --  This is not permitted in internal GNAT implementation units
560            --  except for the case of --! as used by gnatprep output.
561
562            if Is_Special_Character (C) then
563               return;
564            end if;
565
566            --  The only other case in which we allow a character after
567            --  the -- other than a space is when we have a row of minus
568            --  signs (case of header lines for a box comment for example).
569
570            S := Scan_Ptr + 2;
571            while Source (S) >= ' ' loop
572               if Source (S) /= '-' then
573                  if Is_Box_Comment
574                    or else Style_Check_Comments_Spacing = 1
575                  then
576                     Error_Space_Required (Scan_Ptr + 2);
577                  else
578                     Error_Msg -- CODEFIX
579                       ("(style) two spaces required", Scan_Ptr + 2);
580                  end if;
581
582                  return;
583               end if;
584
585               S := S + 1;
586            end loop;
587
588         --  If we are followed by a blank, then the comment is OK if the
589         --  character following this blank is another blank or a format
590         --  effector, or if the required comment spacing is 1.
591
592         elsif Source (Scan_Ptr + 3) <= ' '
593           or else Style_Check_Comments_Spacing = 1
594         then
595            return;
596
597         --  Here is the case where we only have one blank after the two minus
598         --  signs, with Style_Check_Comments_Spacing set to 2, which is an
599         --  error unless the line ends with two minus signs, the case of a
600         --  box comment.
601
602         elsif not Is_Box_Comment then
603            Error_Space_Required (Scan_Ptr + 3);
604         end if;
605      end if;
606   end Check_Comment;
607
608   -------------------
609   -- Check_Dot_Dot --
610   -------------------
611
612   --  In check token mode (-gnatyt), ".." must be surrounded by spaces
613
614   procedure Check_Dot_Dot is
615   begin
616      if Style_Check_Tokens then
617         Require_Preceding_Space;
618         Require_Following_Space;
619      end if;
620   end Check_Dot_Dot;
621
622   ---------------
623   -- Check_EOF --
624   ---------------
625
626   --  In check blanks at end mode, check no blank lines precede the EOF
627
628   procedure Check_EOF is
629   begin
630      if Style_Check_Blank_Lines then
631
632         --  We expect one blank line, from the EOF, but no more than one
633
634         if Blank_Lines = 2 then
635            Error_Msg -- CODEFIX
636              ("(style) blank line not allowed at end of file",
637               Blank_Line_Location);
638
639         elsif Blank_Lines >= 3 then
640            Error_Msg -- CODEFIX
641              ("(style) blank lines not allowed at end of file",
642               Blank_Line_Location);
643         end if;
644      end if;
645   end Check_EOF;
646
647   -----------------------------------
648   -- Check_Exponentiation_Operator --
649   -----------------------------------
650
651   --  No spaces are required for the ** operator in GNAT style check mode
652
653   procedure Check_Exponentiation_Operator is
654   begin
655      null;
656   end Check_Exponentiation_Operator;
657
658   --------------
659   -- Check_HT --
660   --------------
661
662   --  In check horizontal tab mode (-gnatyh), tab characters are not allowed
663
664   procedure Check_HT is
665   begin
666      if Style_Check_Horizontal_Tabs then
667         Error_Msg_S -- CODEFIX
668           ("(style) horizontal tab not allowed");
669      end if;
670   end Check_HT;
671
672   -----------------------
673   -- Check_Indentation --
674   -----------------------
675
676   --  In check indentation mode (-gnaty? for ? a digit), a new statement or
677   --  declaration is required to start in a column that is a multiple of the
678   --  indentation amount.
679
680   procedure Check_Indentation is
681   begin
682      if Style_Check_Indentation /= 0 then
683         if Token_Ptr = First_Non_Blank_Location
684           and then Start_Column rem Style_Check_Indentation /= 0
685         then
686            Error_Msg_SC -- CODEFIX
687              ("(style) bad indentation");
688         end if;
689      end if;
690   end Check_Indentation;
691
692   ----------------------
693   -- Check_Left_Paren --
694   ----------------------
695
696   --  In check token mode (-gnatyt), left paren must not be preceded by an
697   --  identifier character or digit (a separating space is required) and may
698   --  never be followed by a space.
699
700   procedure Check_Left_Paren is
701   begin
702      if Style_Check_Tokens then
703         if Token_Ptr > Source_First (Current_Source_File)
704           and then Identifier_Char (Source (Token_Ptr - 1))
705         then
706            Error_Space_Required (Token_Ptr);
707         end if;
708
709         Check_No_Space_After;
710      end if;
711   end Check_Left_Paren;
712
713   ---------------------------
714   -- Check_Line_Max_Length --
715   ---------------------------
716
717   --  In check max line length mode (-gnatym), the line length must
718   --  not exceed the permitted maximum value.
719
720   procedure Check_Line_Max_Length (Len : Int) is
721   begin
722      if Style_Check_Max_Line_Length then
723         if Len > Style_Max_Line_Length then
724            Error_Msg
725              ("(style) this line is too long",
726               Current_Line_Start + Source_Ptr (Style_Max_Line_Length));
727         end if;
728      end if;
729   end Check_Line_Max_Length;
730
731   ---------------------------
732   -- Check_Line_Terminator --
733   ---------------------------
734
735   --  In check blanks at end mode (-gnatyb), lines may not end with a
736   --  trailing space.
737
738   --  In check form feeds mode (-gnatyf), the line terminator may not
739   --  be either of the characters FF or VT.
740
741   --  In check DOS line terminators node (-gnatyd), the line terminator
742   --  must be a single LF, without a following CR.
743
744   procedure Check_Line_Terminator (Len : Int) is
745      S : Source_Ptr;
746
747      L : Int := Len;
748      --  Length of line (adjusted down for blanks at end of line)
749
750   begin
751      --  Reset count of blank lines if first line
752
753      if Get_Logical_Line_Number (Scan_Ptr) = 1 then
754         Blank_Lines := 0;
755      end if;
756
757      --  Check FF/VT terminators
758
759      if Style_Check_Form_Feeds then
760         if Source (Scan_Ptr) = ASCII.FF then
761            Error_Msg_S -- CODEFIX
762              ("(style) form feed not allowed");
763         elsif Source (Scan_Ptr) = ASCII.VT then
764            Error_Msg_S -- CODEFIX
765              ("(style) vertical tab not allowed");
766         end if;
767      end if;
768
769      --  Check DOS line terminator
770
771      if Style_Check_DOS_Line_Terminator then
772
773         --  Ignore EOF, since we only get called with an EOF if it is the last
774         --  character in the buffer (and was therefore not in the source
775         --  file), since the terminating EOF is added to stop the scan.
776
777         if Source (Scan_Ptr) = EOF then
778            null;
779
780         --  Bad terminator if we don't have an LF
781
782         elsif Source (Scan_Ptr) /= LF then
783            Error_Msg_S ("(style) incorrect line terminator");
784         end if;
785      end if;
786
787      --  Remove trailing spaces
788
789      S := Scan_Ptr;
790      while L > 0 and then Is_White_Space (Source (S - 1)) loop
791         S := S - 1;
792         L := L - 1;
793      end loop;
794
795      --  Issue message for blanks at end of line if option enabled
796
797      if Style_Check_Blanks_At_End and then L < Len then
798         Error_Msg -- CODEFIX
799           ("(style) trailing spaces not permitted", S);
800      end if;
801
802      --  Deal with empty (blank) line
803
804      if L = 0 then
805
806         --  Increment blank line count
807
808         Blank_Lines := Blank_Lines + 1;
809
810         --  If first blank line, record location for later error message
811
812         if Blank_Lines = 1 then
813            Blank_Line_Location := Scan_Ptr;
814         end if;
815
816      --  Non-blank line, check for previous multiple blank lines
817
818      else
819         if Style_Check_Blank_Lines and then Blank_Lines > 1 then
820            Error_Msg -- CODEFIX
821              ("(style) multiple blank lines", Blank_Line_Location);
822         end if;
823
824         --  And reset blank line count
825
826         Blank_Lines := 0;
827      end if;
828   end Check_Line_Terminator;
829
830   ------------------
831   -- Check_Not_In --
832   ------------------
833
834   --  In check tokens mode, only one space between NOT and IN
835
836   procedure Check_Not_In is
837   begin
838      if Style_Check_Tokens then
839         if Source (Token_Ptr - 1) /= ' '
840           or else Token_Ptr - Prev_Token_Ptr /= 4
841         then -- CODEFIX?
842            Error_Msg
843              ("(style) single space must separate NOT and IN", Token_Ptr - 1);
844         end if;
845      end if;
846   end Check_Not_In;
847
848   --------------------------
849   -- Check_No_Space_After --
850   --------------------------
851
852   procedure Check_No_Space_After is
853      S : Source_Ptr;
854
855   begin
856      if Is_White_Space (Source (Scan_Ptr)) then
857
858         --  Allow one or more spaces if followed by comment
859
860         S := Scan_Ptr + 1;
861         loop
862            if Source (S) = '-' and then Source (S + 1) = '-' then
863               return;
864
865            elsif Is_White_Space (Source (S)) then
866               S := S + 1;
867
868            else
869               exit;
870            end if;
871         end loop;
872
873         Error_Space_Not_Allowed (Scan_Ptr);
874      end if;
875   end Check_No_Space_After;
876
877   ---------------------------
878   -- Check_No_Space_Before --
879   ---------------------------
880
881   procedure Check_No_Space_Before is
882   begin
883      if Token_Ptr > First_Non_Blank_Location
884         and then Source (Token_Ptr - 1) <= ' '
885      then
886         Error_Space_Not_Allowed (Token_Ptr - 1);
887      end if;
888   end Check_No_Space_Before;
889
890   -----------------------
891   -- Check_Pragma_Name --
892   -----------------------
893
894   --  In check pragma casing mode (-gnatyp), pragma names must be mixed
895   --  case, i.e. start with an upper case letter, and otherwise lower case,
896   --  except after an underline character.
897
898   procedure Check_Pragma_Name is
899   begin
900      if Style_Check_Pragma_Casing then
901         if Determine_Token_Casing /= Mixed_Case then
902            Error_Msg_SC -- CODEFIX
903              ("(style) bad capitalization, mixed case required");
904         end if;
905      end if;
906   end Check_Pragma_Name;
907
908   -----------------------
909   -- Check_Right_Paren --
910   -----------------------
911
912   --  In check token mode (-gnatyt), right paren must not be immediately
913   --  followed by an identifier character, and must never be preceded by
914   --  a space unless it is the initial non-blank character on the line.
915
916   procedure Check_Right_Paren is
917   begin
918      if Style_Check_Tokens then
919         if Identifier_Char (Source (Token_Ptr + 1)) then
920            Error_Space_Required (Token_Ptr + 1);
921         end if;
922
923         Check_No_Space_Before;
924      end if;
925   end Check_Right_Paren;
926
927   ---------------------
928   -- Check_Semicolon --
929   ---------------------
930
931   --  In check token mode (-gnatyt), semicolon does not permit a preceding
932   --  space and a following space is required.
933
934   procedure Check_Semicolon is
935   begin
936      if Style_Check_Tokens then
937         Check_No_Space_Before;
938
939         if Source (Scan_Ptr) > ' ' then
940            Error_Space_Required (Scan_Ptr);
941         end if;
942      end if;
943   end Check_Semicolon;
944
945   -------------------------------
946   -- Check_Separate_Stmt_Lines --
947   -------------------------------
948
949   procedure Check_Separate_Stmt_Lines is
950   begin
951      if Style_Check_Separate_Stmt_Lines then
952         Check_Separate_Stmt_Lines_Cont;
953      end if;
954   end Check_Separate_Stmt_Lines;
955
956   ------------------------------------
957   -- Check_Separate_Stmt_Lines_Cont --
958   ------------------------------------
959
960   procedure Check_Separate_Stmt_Lines_Cont is
961      S : Source_Ptr;
962
963   begin
964      --  Skip past white space
965
966      S := Scan_Ptr;
967      while Is_White_Space (Source (S)) loop
968         S := S + 1;
969      end loop;
970
971      --  Line terminator is OK
972
973      if Source (S) in Line_Terminator then
974         return;
975
976      --  Comment is OK
977
978      elsif Source (S) = '-' and then Source (S + 1) = '-' then
979         return;
980
981      --  ABORT keyword is OK after THEN (THEN ABORT case)
982
983      elsif Token = Tok_Then
984        and then (Source (S + 0) = 'a' or else Source (S + 0) = 'A')
985        and then (Source (S + 1) = 'b' or else Source (S + 1) = 'B')
986        and then (Source (S + 2) = 'o' or else Source (S + 2) = 'O')
987        and then (Source (S + 3) = 'r' or else Source (S + 3) = 'R')
988        and then (Source (S + 4) = 't' or else Source (S + 4) = 'T')
989        and then (Source (S + 5) in Line_Terminator
990                   or else Is_White_Space (Source (S + 5)))
991      then
992         return;
993
994      --  PRAGMA keyword is OK after ELSE
995
996      elsif Token = Tok_Else
997        and then (Source (S + 0) = 'p' or else Source (S + 0) = 'P')
998        and then (Source (S + 1) = 'r' or else Source (S + 1) = 'R')
999        and then (Source (S + 2) = 'a' or else Source (S + 2) = 'A')
1000        and then (Source (S + 3) = 'g' or else Source (S + 3) = 'G')
1001        and then (Source (S + 4) = 'm' or else Source (S + 4) = 'M')
1002        and then (Source (S + 5) = 'a' or else Source (S + 5) = 'A')
1003        and then (Source (S + 6) in Line_Terminator
1004                   or else Is_White_Space (Source (S + 6)))
1005      then
1006         return;
1007
1008         --  Otherwise we have the style violation we are looking for
1009
1010      else
1011         if Token = Tok_Then then
1012            Error_Msg -- CODEFIX
1013              ("(style) no statements may follow THEN on same line", S);
1014         else
1015            Error_Msg
1016              ("(style) no statements may follow ELSE on same line", S);
1017         end if;
1018      end if;
1019   end Check_Separate_Stmt_Lines_Cont;
1020
1021   ----------------
1022   -- Check_Then --
1023   ----------------
1024
1025   --  In check if then layout mode (-gnatyi), we expect a THEN keyword to
1026   --  appear either on the same line as the IF, or on a separate line if
1027   --  the IF statement extends for more than one line.
1028
1029   procedure Check_Then (If_Loc : Source_Ptr) is
1030   begin
1031      if Style_Check_If_Then_Layout then
1032         declare
1033            If_Line   : constant Physical_Line_Number :=
1034              Get_Physical_Line_Number (If_Loc);
1035            Then_Line : constant Physical_Line_Number :=
1036              Get_Physical_Line_Number (Token_Ptr);
1037         begin
1038            if If_Line = Then_Line then
1039               null;
1040            elsif Token_Ptr /= First_Non_Blank_Location then
1041               Error_Msg_SC ("(style) misplaced THEN");
1042            end if;
1043         end;
1044      end if;
1045   end Check_Then;
1046
1047   -------------------------------
1048   -- Check_Unary_Plus_Or_Minus --
1049   -------------------------------
1050
1051   --  In check token mode (-gnatyt), unary plus or minus must not be
1052   --  followed by a space.
1053
1054   --  Annoying exception: if we have the sequence =>+ within a Depends pragma
1055   --  or aspect, then we insist on a space rather than forbidding it.
1056
1057   procedure Check_Unary_Plus_Or_Minus (Inside_Depends : Boolean := False) is
1058   begin
1059      if Style_Check_Tokens then
1060         if not Inside_Depends then
1061            Check_No_Space_After;
1062         else
1063            Require_Following_Space;
1064         end if;
1065      end if;
1066   end Check_Unary_Plus_Or_Minus;
1067
1068   ------------------------
1069   -- Check_Vertical_Bar --
1070   ------------------------
1071
1072   --  In check token mode (-gnatyt), vertical bar must be surrounded by spaces
1073
1074   procedure Check_Vertical_Bar is
1075   begin
1076      if Style_Check_Tokens then
1077         Require_Preceding_Space;
1078         Require_Following_Space;
1079      end if;
1080   end Check_Vertical_Bar;
1081
1082   -----------------------
1083   -- Check_Xtra_Parens --
1084   -----------------------
1085
1086   procedure Check_Xtra_Parens (Loc : Source_Ptr) is
1087   begin
1088      if Style_Check_Xtra_Parens then
1089         Error_Msg -- CODEFIX
1090           ("(style) redundant parentheses", Loc);
1091      end if;
1092   end Check_Xtra_Parens;
1093
1094   ----------------------------
1095   -- Determine_Token_Casing --
1096   ----------------------------
1097
1098   function Determine_Token_Casing return Casing_Type is
1099   begin
1100      return Determine_Casing (Source (Token_Ptr .. Scan_Ptr - 1));
1101   end Determine_Token_Casing;
1102
1103   -----------------------------
1104   -- Error_Space_Not_Allowed --
1105   -----------------------------
1106
1107   procedure Error_Space_Not_Allowed (S : Source_Ptr) is
1108   begin
1109      Error_Msg -- CODEFIX
1110        ("(style) space not allowed", S);
1111   end Error_Space_Not_Allowed;
1112
1113   --------------------------
1114   -- Error_Space_Required --
1115   --------------------------
1116
1117   procedure Error_Space_Required (S : Source_Ptr) is
1118   begin
1119      Error_Msg -- CODEFIX
1120        ("(style) space required", S);
1121   end Error_Space_Required;
1122
1123   --------------------
1124   -- Is_White_Space --
1125   --------------------
1126
1127   function Is_White_Space (C : Character) return Boolean is
1128   begin
1129      return C = ' ' or else C = HT;
1130   end Is_White_Space;
1131
1132   -------------------
1133   -- Mode_In_Check --
1134   -------------------
1135
1136   function Mode_In_Check return Boolean is
1137   begin
1138      return Style_Check and Style_Check_Mode_In;
1139   end Mode_In_Check;
1140
1141   -----------------
1142   -- No_End_Name --
1143   -----------------
1144
1145   --  In check end/exit labels mode (-gnatye), always require the name of
1146   --  a subprogram or package to be present on the END, so this is an error.
1147
1148   procedure No_End_Name (Name : Node_Id) is
1149   begin
1150      if Style_Check_End_Labels then
1151         Error_Msg_Node_1 := Name;
1152         Error_Msg_SP -- CODEFIX
1153           ("(style) `END &` required");
1154      end if;
1155   end No_End_Name;
1156
1157   ------------------
1158   -- No_Exit_Name --
1159   ------------------
1160
1161   --  In check end/exit labels mode (-gnatye), always require the name of
1162   --  the loop to be present on the EXIT when exiting a named loop.
1163
1164   procedure No_Exit_Name (Name : Node_Id) is
1165   begin
1166      if Style_Check_End_Labels then
1167         Error_Msg_Node_1 := Name;
1168         Error_Msg_SP -- CODEFIX
1169           ("(style) `EXIT &` required");
1170      end if;
1171   end No_Exit_Name;
1172
1173   ----------------------------
1174   -- Non_Lower_Case_Keyword --
1175   ----------------------------
1176
1177   --  In check casing mode (-gnatyk), reserved keywords must be spelled
1178   --  in all lower case (excluding keywords range, access, delta and digits
1179   --  used as attribute designators).
1180
1181   procedure Non_Lower_Case_Keyword is
1182   begin
1183      if Style_Check_Keyword_Casing then
1184         Error_Msg_SC -- CODEFIX
1185           ("(style) reserved words must be all lower case");
1186      end if;
1187   end Non_Lower_Case_Keyword;
1188
1189   -----------------------------
1190   -- Require_Following_Space --
1191   -----------------------------
1192
1193   procedure Require_Following_Space is
1194   begin
1195      if Source (Scan_Ptr) > ' ' then
1196         Error_Space_Required (Scan_Ptr);
1197      end if;
1198   end Require_Following_Space;
1199
1200   -----------------------------
1201   -- Require_Preceding_Space --
1202   -----------------------------
1203
1204   procedure Require_Preceding_Space is
1205   begin
1206      if Token_Ptr > Source_First (Current_Source_File)
1207        and then Source (Token_Ptr - 1) > ' '
1208      then
1209         Error_Space_Required (Token_Ptr);
1210      end if;
1211   end Require_Preceding_Space;
1212
1213end Styleg;
1214