gcc/ada/pprint.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                               P P R I N T                                --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2008-2016, 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 with Atree;   use Atree;
  27 with Einfo;   use Einfo;
  28 with Namet;   use Namet;
  29 with Nlists;  use Nlists;
  30 with Opt;     use Opt;
  31 with Sinfo;   use Sinfo;
  32 with Sinput;  use Sinput;
  33 with Snames;  use Snames;
  34 with Uintp;   use Uintp;
  35
  36 package body Pprint is
  37
  38    List_Name_Count : Integer := 0;
  39    --  Counter used to prevent infinite recursion while computing name of
  40    --  complex expressions.
  41
  42    ----------------------
  43    -- Expression_Image --
  44    ----------------------
  45
  46    function Expression_Image
  47      (Expr    : Node_Id;
  48       Default : String) return String
  49    is
  50       From_Source  : constant Boolean :=
  51                        Comes_From_Source (Expr)
  52                          and then not Opt.Debug_Generated_Code;
  53       Append_Paren : Boolean := False;
  54       Left         : Node_Id := Original_Node (Expr);
  55       Right        : Node_Id := Original_Node (Expr);
  56
  57       function Expr_Name
  58         (Expr        : Node_Id;
  59          Take_Prefix : Boolean := True;
  60          Expand_Type : Boolean := True) return String;
  61       --  Return string corresponding to Expr. If no string can be extracted,
  62       --  return "...". If Take_Prefix is True, go back to prefix when needed,
  63       --  otherwise only consider the right-hand side of an expression. If
  64       --  Expand_Type is True and Expr is a type, try to expand Expr (an
  65       --  internally generated type) into a user understandable name.
  66
  67       Max_List : constant := 3;
  68       --  Limit number of list elements to dump
  69
  70       Max_Expr_Elements : constant := 24;
  71       --  Limit number of elements in an expression for use by Expr_Name
  72
  73       Num_Elements : Natural := 0;
  74       --  Current number of elements processed by Expr_Name
  75
  76       function List_Name
  77         (List      : Node_Id;
  78          Add_Space : Boolean := True;
  79          Add_Paren : Boolean := True) return String;
  80       --  Return a string corresponding to List
  81
  82       ---------------
  83       -- List_Name --
  84       ---------------
  85
  86       function List_Name
  87         (List      : Node_Id;
  88          Add_Space : Boolean := True;
  89          Add_Paren : Boolean := True) return String
  90       is
  91          function Internal_List_Name
  92            (List      : Node_Id;
  93             First     : Boolean := True;
  94             Add_Space : Boolean := True;
  95             Add_Paren : Boolean := True;
  96             Num       : Natural := 1) return String;
  97          --  ??? what does this do
  98
  99          ------------------------
 100          -- Internal_List_Name --
 101          ------------------------
 102
 103          function Internal_List_Name
 104            (List      : Node_Id;
 105             First     : Boolean := True;
 106             Add_Space : Boolean := True;
 107             Add_Paren : Boolean := True;
 108             Num       : Natural := 1) return String
 109          is
 110             function Prepend (S : String) return String;
 111             --  ??? what does this do
 112
 113             -------------
 114             -- Prepend --
 115             -------------
 116
 117             function Prepend (S : String) return String is
 118             begin
 119                if Add_Space then
 120                   if Add_Paren then
 121                      return " (" & S;
 122                   else
 123                      return ' ' & S;
 124                   end if;
 125                elsif Add_Paren then
 126                   return '(' & S;
 127                else
 128                   return S;
 129                end if;
 130             end Prepend;
 131
 132          --  Start of processing for Internal_List_Name
 133
 134          begin
 135             if not Present (List) then
 136                if First or else not Add_Paren then
 137                   return "";
 138                else
 139                   return ")";
 140                end if;
 141             elsif Num > Max_List then
 142                if Add_Paren then
 143                   return ", ...)";
 144                else
 145                   return ", ...";
 146                end if;
 147             end if;
 148
 149             --  ??? the Internal_List_Name calls can be factored out
 150
 151             if First then
 152                return Prepend (Expr_Name (List)
 153                  & Internal_List_Name
 154                      (List      => Next (List),
 155                       First     => False,
 156                       Add_Paren => Add_Paren,
 157                       Num       => Num + 1));
 158             else
 159                return ", " & Expr_Name (List)
 160                  & Internal_List_Name
 161                      (List      => Next (List),
 162                       First     => False,
 163                       Add_Paren => Add_Paren,
 164                       Num       => Num + 1);
 165             end if;
 166          end Internal_List_Name;
 167
 168       --  Start of processing for List_Name
 169
 170       begin
 171          --  Prevent infinite recursion by limiting depth to 3
 172
 173          if List_Name_Count > 3 then
 174             return "...";
 175          end if;
 176
 177          List_Name_Count := List_Name_Count + 1;
 178
 179          declare
 180             Result : constant String :=
 181                        Internal_List_Name
 182                          (List      => List,
 183                           Add_Space => Add_Space,
 184                           Add_Paren => Add_Paren);
 185          begin
 186             List_Name_Count := List_Name_Count - 1;
 187             return Result;
 188          end;
 189       end List_Name;
 190
 191       ---------------
 192       -- Expr_Name --
 193       ---------------
 194
 195       function Expr_Name
 196         (Expr        : Node_Id;
 197          Take_Prefix : Boolean := True;
 198          Expand_Type : Boolean := True) return String
 199       is
 200       begin
 201          Num_Elements := Num_Elements + 1;
 202
 203          if Num_Elements > Max_Expr_Elements then
 204             return "...";
 205          end if;
 206
 207          case Nkind (Expr) is
 208             when N_Defining_Identifier | N_Identifier =>
 209                return Ident_Image (Expr, Expression_Image.Expr, Expand_Type);
 210
 211             when N_Character_Literal =>
 212                declare
 213                   Char : constant Int :=
 214                            UI_To_Int (Char_Literal_Value (Expr));
 215                begin
 216                   if Char in 32 .. 127 then
 217                      return "'" & Character'Val (Char) & "'";
 218                   else
 219                      UI_Image (Char_Literal_Value (Expr));
 220                      return
 221                        "'\" & UI_Image_Buffer (1 .. UI_Image_Length) & "'";
 222                   end if;
 223                end;
 224
 225             when N_Integer_Literal =>
 226                UI_Image (Intval (Expr));
 227                return UI_Image_Buffer (1 .. UI_Image_Length);
 228
 229             when N_Real_Literal =>
 230                return Real_Image (Realval (Expr));
 231
 232             when N_String_Literal =>
 233                return String_Image (Strval (Expr));
 234
 235             when N_Allocator =>
 236                return "new " & Expr_Name (Expression (Expr));
 237
 238             when N_Aggregate =>
 239                if Present (Sinfo.Expressions (Expr)) then
 240                   return
 241                     List_Name
 242                       (List      => First (Sinfo.Expressions (Expr)),
 243                        Add_Space => False);
 244
 245                --  Do not return empty string for (others => <>) aggregate
 246                --  of a componentless record type. At least one caller (the
 247                --  recursive call below in the N_Qualified_Expression case)
 248                --  is not prepared to deal with a zero-length result.
 249
 250                elsif Null_Record_Present (Expr)
 251                  or else not Present (First (Component_Associations (Expr)))
 252                then
 253                   return ("(null record)");
 254
 255                else
 256                   return
 257                     List_Name
 258                       (List      => First (Component_Associations (Expr)),
 259                        Add_Space => False,
 260                        Add_Paren => False);
 261                end if;
 262
 263             when N_Extension_Aggregate =>
 264                return "(" & Expr_Name (Ancestor_Part (Expr)) & " with "
 265                  & List_Name
 266                      (List      => First (Sinfo.Expressions (Expr)),
 267                       Add_Space => False,
 268                       Add_Paren => False) & ")";
 269
 270             when N_Attribute_Reference =>
 271                if Take_Prefix then
 272                   declare
 273                      Id     : constant Attribute_Id :=
 274                                 Get_Attribute_Id (Attribute_Name (Expr));
 275                      Str    : constant String :=
 276                                 Expr_Name (Prefix (Expr)) & "'"
 277                                   & Get_Name_String (Attribute_Name (Expr));
 278                      N      : Node_Id;
 279                      Ranges : List_Id;
 280
 281                   begin
 282                      if (Id = Attribute_First or else Id = Attribute_Last)
 283                        and then Str (Str'First) = '$'
 284                      then
 285                         N := Associated_Node_For_Itype (Etype (Prefix (Expr)));
 286
 287                         if Present (N) then
 288                            if Nkind (N) = N_Full_Type_Declaration then
 289                               N := Type_Definition (N);
 290                            end if;
 291
 292                            if Nkind (N) = N_Subtype_Declaration then
 293                               Ranges :=
 294                                 Constraints
 295                                   (Constraint (Subtype_Indication (N)));
 296
 297                               if List_Length (Ranges) = 1
 298                                 and then
 299                                   Nkind_In
 300                                     (First (Ranges),
 301                                      N_Range,
 302                                      N_Real_Range_Specification,
 303                                      N_Signed_Integer_Type_Definition)
 304                               then
 305                                  if Id = Attribute_First then
 306                                     return
 307                                       Expression_Image
 308                                         (Low_Bound (First (Ranges)), Str);
 309                                  else
 310                                     return
 311                                       Expression_Image
 312                                         (High_Bound (First (Ranges)), Str);
 313                                  end if;
 314                               end if;
 315                            end if;
 316                         end if;
 317                      end if;
 318
 319                      return Str;
 320                   end;
 321                else
 322                   return "'" & Get_Name_String (Attribute_Name (Expr));
 323                end if;
 324
 325             when N_Explicit_Dereference =>
 326
 327                --  Return "Foo" instead of "Parameter_Block.Foo.all"
 328
 329                if Hide_Parameter_Blocks
 330                  and then Nkind (Prefix (Expr)) = N_Selected_Component
 331                  and then Present (Etype (Prefix (Expr)))
 332                  and then Is_Access_Type (Etype (Prefix (Expr)))
 333                  and then Is_Param_Block_Component_Type (Etype (Prefix (Expr)))
 334                then
 335                   return Expr_Name (Selector_Name (Prefix (Expr)));
 336
 337                elsif Take_Prefix then
 338                   return Expr_Name (Prefix (Expr)) & ".all";
 339                else
 340                   return ".all";
 341                end if;
 342
 343             when N_Expanded_Name | N_Selected_Component =>
 344                if Take_Prefix then
 345                   return
 346                     Expr_Name (Prefix (Expr)) & "." &
 347                     Expr_Name (Selector_Name (Expr));
 348                else
 349                   return "." & Expr_Name (Selector_Name (Expr));
 350                end if;
 351
 352             when N_Component_Association =>
 353                return "("
 354                  & List_Name
 355                      (List      => First (Choices (Expr)),
 356                       Add_Space => False,
 357                       Add_Paren => False)
 358                  & " => " & Expr_Name (Expression (Expr)) & ")";
 359
 360             when N_If_Expression =>
 361                declare
 362                   N : constant Node_Id := First (Sinfo.Expressions (Expr));
 363                begin
 364                   return
 365                     "if " & Expr_Name (N) & " then "
 366                       & Expr_Name (Next (N)) & " else "
 367                       & Expr_Name (Next (Next (N)));
 368                end;
 369
 370             when N_Qualified_Expression =>
 371                declare
 372                   Mark : constant String :=
 373                            Expr_Name
 374                              (Subtype_Mark (Expr), Expand_Type => False);
 375                   Str  : constant String := Expr_Name (Expression (Expr));
 376                begin
 377                   if Str (Str'First) = '(' and then Str (Str'Last) = ')' then
 378                      return Mark & "'" & Str;
 379                   else
 380                      return Mark & "'(" & Str & ")";
 381                   end if;
 382                end;
 383
 384             when N_Unchecked_Expression | N_Expression_With_Actions =>
 385                return Expr_Name (Expression (Expr));
 386
 387             when N_Raise_Constraint_Error =>
 388                if Present (Condition (Expr)) then
 389                   return
 390                     "[constraint_error when "
 391                       & Expr_Name (Condition (Expr)) & "]";
 392                else
 393                   return "[constraint_error]";
 394                end if;
 395
 396             when N_Raise_Program_Error =>
 397                if Present (Condition (Expr)) then
 398                   return
 399                     "[program_error when "
 400                       & Expr_Name (Condition (Expr)) & "]";
 401                else
 402                   return "[program_error]";
 403                end if;
 404
 405             when N_Range =>
 406                return
 407                  Expr_Name (Low_Bound (Expr)) & ".." &
 408                  Expr_Name (High_Bound (Expr));
 409
 410             when N_Slice =>
 411                return
 412                  Expr_Name (Prefix (Expr)) & " (" &
 413                  Expr_Name (Discrete_Range (Expr)) & ")";
 414
 415             when N_And_Then =>
 416                return
 417                  Expr_Name (Left_Opnd (Expr)) & " and then " &
 418                  Expr_Name (Right_Opnd (Expr));
 419
 420             when N_In =>
 421                return
 422                  Expr_Name (Left_Opnd (Expr)) & " in " &
 423                  Expr_Name (Right_Opnd (Expr));
 424
 425             when N_Not_In =>
 426                return
 427                  Expr_Name (Left_Opnd (Expr)) & " not in " &
 428                  Expr_Name (Right_Opnd (Expr));
 429
 430             when N_Or_Else =>
 431                return
 432                  Expr_Name (Left_Opnd (Expr)) & " or else " &
 433                  Expr_Name (Right_Opnd (Expr));
 434
 435             when N_Op_And =>
 436                return
 437                  Expr_Name (Left_Opnd (Expr)) & " and " &
 438                  Expr_Name (Right_Opnd (Expr));
 439
 440             when N_Op_Or =>
 441                return
 442                  Expr_Name (Left_Opnd (Expr)) & " or " &
 443                  Expr_Name (Right_Opnd (Expr));
 444
 445             when N_Op_Xor =>
 446                return
 447                  Expr_Name (Left_Opnd (Expr)) & " xor " &
 448                  Expr_Name (Right_Opnd (Expr));
 449
 450             when N_Op_Eq =>
 451                return
 452                  Expr_Name (Left_Opnd (Expr)) & " = " &
 453                  Expr_Name (Right_Opnd (Expr));
 454
 455             when N_Op_Ne =>
 456                return
 457                  Expr_Name (Left_Opnd (Expr)) & " /= " &
 458                  Expr_Name (Right_Opnd (Expr));
 459
 460             when N_Op_Lt =>
 461                return
 462                  Expr_Name (Left_Opnd (Expr)) & " < " &
 463                  Expr_Name (Right_Opnd (Expr));
 464
 465             when N_Op_Le =>
 466                return
 467                  Expr_Name (Left_Opnd (Expr)) & " <= " &
 468                  Expr_Name (Right_Opnd (Expr));
 469
 470             when N_Op_Gt =>
 471                return
 472                  Expr_Name (Left_Opnd (Expr)) & " > " &
 473                  Expr_Name (Right_Opnd (Expr));
 474
 475             when N_Op_Ge =>
 476                return
 477                  Expr_Name (Left_Opnd (Expr)) & " >= " &
 478                  Expr_Name (Right_Opnd (Expr));
 479
 480             when N_Op_Add =>
 481                return
 482                  Expr_Name (Left_Opnd (Expr)) & " + " &
 483                  Expr_Name (Right_Opnd (Expr));
 484
 485             when N_Op_Subtract =>
 486                return
 487                  Expr_Name (Left_Opnd (Expr)) & " - " &
 488                  Expr_Name (Right_Opnd (Expr));
 489
 490             when N_Op_Multiply =>
 491                return
 492                  Expr_Name (Left_Opnd (Expr)) & " * " &
 493                  Expr_Name (Right_Opnd (Expr));
 494
 495             when N_Op_Divide =>
 496                return
 497                  Expr_Name (Left_Opnd (Expr)) & " / " &
 498                  Expr_Name (Right_Opnd (Expr));
 499
 500             when N_Op_Mod =>
 501                return
 502                  Expr_Name (Left_Opnd (Expr)) & " mod " &
 503                  Expr_Name (Right_Opnd (Expr));
 504
 505             when N_Op_Rem =>
 506                return
 507                  Expr_Name (Left_Opnd (Expr)) & " rem " &
 508                  Expr_Name (Right_Opnd (Expr));
 509
 510             when N_Op_Expon =>
 511                return
 512                  Expr_Name (Left_Opnd (Expr)) & " ** " &
 513                  Expr_Name (Right_Opnd (Expr));
 514
 515             when N_Op_Shift_Left =>
 516                return
 517                  Expr_Name (Left_Opnd (Expr)) & " << " &
 518                  Expr_Name (Right_Opnd (Expr));
 519
 520             when N_Op_Shift_Right | N_Op_Shift_Right_Arithmetic =>
 521                return
 522                  Expr_Name (Left_Opnd (Expr)) & " >> " &
 523                  Expr_Name (Right_Opnd (Expr));
 524
 525             when N_Op_Concat =>
 526                return
 527                  Expr_Name (Left_Opnd (Expr)) & " & " &
 528                  Expr_Name (Right_Opnd (Expr));
 529
 530             when N_Op_Plus =>
 531                return "+" & Expr_Name (Right_Opnd (Expr));
 532
 533             when N_Op_Minus =>
 534                return "-" & Expr_Name (Right_Opnd (Expr));
 535
 536             when N_Op_Abs =>
 537                return "abs " & Expr_Name (Right_Opnd (Expr));
 538
 539             when N_Op_Not =>
 540                return "not (" & Expr_Name (Right_Opnd (Expr)) & ")";
 541
 542             when N_Parameter_Association =>
 543                return Expr_Name (Explicit_Actual_Parameter (Expr));
 544
 545             when N_Type_Conversion =>
 546
 547                --  Most conversions are not very interesting (used inside
 548                --  expanded checks to convert to larger ranges), so skip them.
 549
 550                return Expr_Name (Expression (Expr));
 551
 552             when N_Unchecked_Type_Conversion =>
 553
 554                --  Only keep the type conversion in complex cases
 555
 556                if not Is_Scalar_Type (Etype (Expr))
 557                  or else not Is_Scalar_Type (Etype (Expression (Expr)))
 558                  or else Is_Modular_Integer_Type (Etype (Expr))
 559                          /= Is_Modular_Integer_Type (Etype (Expression (Expr)))
 560                then
 561                   return Expr_Name (Subtype_Mark (Expr)) &
 562                     "(" & Expr_Name (Expression (Expr)) & ")";
 563                else
 564                   return Expr_Name (Expression (Expr));
 565                end if;
 566
 567             when N_Indexed_Component =>
 568                if Take_Prefix then
 569                   return
 570                     Expr_Name (Prefix (Expr))
 571                       & List_Name (First (Sinfo.Expressions (Expr)));
 572                else
 573                   return List_Name (First (Sinfo.Expressions (Expr)));
 574                end if;
 575
 576             when N_Function_Call =>
 577
 578                --  If Default = "", it means we're expanding the name of
 579                --  a gnat temporary (and not really a function call), so add
 580                --  parentheses around function call to mark it specially.
 581
 582                if Default = "" then
 583                   return '('
 584                     & Expr_Name (Name (Expr))
 585                     & List_Name (First (Sinfo.Parameter_Associations (Expr)))
 586                     & ')';
 587                else
 588                   return
 589                     Expr_Name (Name (Expr))
 590                       & List_Name
 591                           (First (Sinfo.Parameter_Associations (Expr)));
 592                end if;
 593
 594             when N_Null =>
 595                return "null";
 596
 597             when N_Others_Choice =>
 598                return "others";
 599
 600             when others =>
 601                return "...";
 602          end case;
 603       end Expr_Name;
 604
 605    --  Start of processing for Expression_Name
 606
 607    begin
 608       if not From_Source then
 609          declare
 610             S : constant String := Expr_Name (Expr);
 611          begin
 612             if S = "..." then
 613                return Default;
 614             else
 615                return S;
 616             end if;
 617          end;
 618       end if;
 619
 620       --  Compute left (start) and right (end) slocs for the expression
 621       --  Consider using Sinput.Sloc_Range instead, except that it does not
 622       --  work properly currently???
 623
 624       loop
 625          case Nkind (Left) is
 626             when N_And_Then                   |
 627                  N_Binary_Op                  |
 628                  N_Membership_Test            |
 629                  N_Or_Else                    =>
 630                Left := Original_Node (Left_Opnd (Left));
 631
 632             when N_Attribute_Reference        |
 633                  N_Expanded_Name              |
 634                  N_Explicit_Dereference       |
 635                  N_Indexed_Component          |
 636                  N_Reference                  |
 637                  N_Selected_Component         |
 638                  N_Slice                      =>
 639                Left := Original_Node (Prefix (Left));
 640
 641             when N_Defining_Program_Unit_Name |
 642                  N_Designator                 |
 643                  N_Function_Call              =>
 644                Left := Original_Node (Name (Left));
 645
 646             when N_Range =>
 647                Left := Original_Node (Low_Bound (Left));
 648
 649             when N_Type_Conversion =>
 650                Left := Original_Node (Subtype_Mark (Left));
 651
 652             --  For any other item, quit loop
 653
 654             when others =>
 655                exit;
 656          end case;
 657       end loop;
 658
 659       loop
 660          case Nkind (Right) is
 661             when N_And_Then           |
 662                  N_Membership_Test    |
 663                  N_Op                 |
 664                  N_Or_Else            =>
 665                Right := Original_Node (Right_Opnd (Right));
 666
 667             when N_Expanded_Name      |
 668                  N_Selected_Component =>
 669                Right := Original_Node (Selector_Name (Right));
 670
 671             when N_Designator =>
 672                Right := Original_Node (Identifier (Right));
 673
 674             when N_Defining_Program_Unit_Name =>
 675                Right := Original_Node (Defining_Identifier (Right));
 676
 677             when N_Range =>
 678                Right := Original_Node (High_Bound (Right));
 679
 680             when N_Parameter_Association =>
 681                Right := Original_Node (Explicit_Actual_Parameter (Right));
 682
 683             when N_Indexed_Component =>
 684                Right := Original_Node (Last (Sinfo.Expressions (Right)));
 685                Append_Paren := True;
 686
 687             when N_Function_Call =>
 688                if Present (Sinfo.Parameter_Associations (Right)) then
 689                   declare
 690                      Rover : Node_Id;
 691                      Found : Boolean;
 692
 693                   begin
 694                      --  Avoid source position confusion associated with
 695                      --  parameters for which Comes_From_Source is False.
 696
 697                      Rover := First (Sinfo.Parameter_Associations (Right));
 698                      Found := False;
 699                      while Present (Rover) loop
 700                         if Comes_From_Source (Original_Node (Rover)) then
 701                            Right := Original_Node (Rover);
 702                            Append_Paren := True;
 703                            Found := True;
 704                         end if;
 705
 706                         Next (Rover);
 707                      end loop;
 708
 709                      --  Quit loop if no Comes_From_Source parameters
 710
 711                      exit when not Found;
 712                   end;
 713
 714                --  Quit loop if no parameters
 715
 716                else
 717                   exit;
 718                end if;
 719
 720             when N_Quantified_Expression =>
 721                Right := Original_Node (Condition (Right));
 722
 723             --  For all other items, quit the loop
 724
 725             when others =>
 726                exit;
 727          end case;
 728       end loop;
 729
 730       declare
 731          Scn      : Source_Ptr := Original_Location (Sloc (Left));
 732          End_Sloc : constant Source_Ptr :=
 733                       Original_Location (Sloc (Right));
 734          Src      : constant Source_Buffer_Ptr :=
 735                       Source_Text (Get_Source_File_Index (Scn));
 736
 737       begin
 738          if Scn > End_Sloc then
 739             return Default;
 740          end if;
 741
 742          declare
 743             Buffer           : String (1 .. Natural (End_Sloc - Scn));
 744             Index            : Natural := 0;
 745             Skipping_Comment : Boolean := False;
 746             Underscore       : Boolean := False;
 747
 748          begin
 749             if Right /= Expr then
 750                while Scn < End_Sloc loop
 751                   case Src (Scn) is
 752                   when ' ' | ASCII.HT =>
 753                      if not Skipping_Comment and then not Underscore then
 754                         Underscore := True;
 755                         Index := Index + 1;
 756                         Buffer (Index) := ' ';
 757                      end if;
 758
 759                   --  CR/LF/FF is the end of any comment
 760
 761                   when ASCII.LF | ASCII.CR | ASCII.FF =>
 762                      Skipping_Comment := False;
 763
 764                   when others =>
 765                      Underscore := False;
 766
 767                      if not Skipping_Comment then
 768
 769                         --  Ignore comment
 770
 771                         if Src (Scn) = '-' and then Src (Scn + 1) = '-' then
 772                            Skipping_Comment := True;
 773
 774                         else
 775                            Index := Index + 1;
 776                            Buffer (Index) := Src (Scn);
 777                         end if;
 778                      end if;
 779                   end case;
 780
 781                   Scn := Scn + 1;
 782                end loop;
 783             end if;
 784
 785             if Index < 1 then
 786                declare
 787                   S : constant String := Expr_Name (Right);
 788                begin
 789                   if S = "..." then
 790                      return Default;
 791                   else
 792                      return S;
 793                   end if;
 794                end;
 795
 796             elsif Append_Paren then
 797                return Buffer (1 .. Index) & Expr_Name (Right, False) & ')';
 798
 799             else
 800                return Buffer (1 .. Index) & Expr_Name (Right, False);
 801             end if;
 802          end;
 803       end;
 804    end Expression_Image;
 805
 806 end Pprint;