diff options
Diffstat (limited to 'gcc/ada/sinput.ads')
| -rw-r--r-- | gcc/ada/sinput.ads | 65 |
1 files changed, 51 insertions, 14 deletions
diff --git a/gcc/ada/sinput.ads b/gcc/ada/sinput.ads index 53e8889b424..b47b4dc2f89 100644 --- a/gcc/ada/sinput.ads +++ b/gcc/ada/sinput.ads @@ -6,7 +6,7 @@ -- -- -- S p e c -- -- -- --- Copyright (C) 1992-2004 Free Software Foundation, Inc. -- +-- Copyright (C) 1992-2005 Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- @@ -37,8 +37,32 @@ -- General Note: throughout the compiler, we use the term line or source -- line to refer to a physical line in the source, terminated by the end of --- physical line sequence. See Skip_Line_Terminators procedure for a full --- description of the difference between logical and physical lines. +-- physical line sequence. + +-- There are two distinct concepts of line terminator in GNAT + +-- A logical line terminator is what corresponds to the "end of a line" as +-- described in RM 2.2 (13). Any of the characters FF, LF, CR or VT or any +-- wide character that is a Line or Paragraph Separator acts as an end of +-- logical line in this sense, and it is essentially irrelevant whether one +-- or more appears in sequence (since if sequence of such characters is +-- regarded as separate ends of line, then the intervening logical lines +-- are null in any case). + +-- A physical line terminator is a sequence of format effectors that is +-- treated as ending a physical line. Physical lines have no Ada semantic +-- significance, but they are significant for error reporting purposes, +-- since errors are identified by line and column location. + +-- In GNAT, a physical line is ended by any of the sequences LF, CR/LF, CR or +-- LF/CR. LF is used in typical Unix systems, CR/LF in DOS systems, and CR +-- alone in System 7. We don't know of any system using LF/CR, but it seems +-- reasonable to include this case for consistency. In addition, we recognize +-- any of these sequences in any of the operating systems, for better +-- behavior in treating foreign files (e.g. a Unix file with LF terminators +-- transferred to a DOS system). Finally, wide character codes in cagtegories +-- Separator, Line and Separator, Paragraph are considered to be physical +-- line terminators. with Alloc; with Casing; use Casing; @@ -293,7 +317,7 @@ package Sinput is procedure Lock; -- Lock internal tables - Main_Source_File : Source_File_Index; + Main_Source_File : Source_File_Index := No_Source_File; -- This is set to the source file index of the main unit ----------------------------- @@ -531,16 +555,29 @@ package Sinput is procedure Skip_Line_Terminators (P : in out Source_Ptr; Physical : out Boolean); - -- On entry, Source (P) points to the line terminator character that - -- terminates a line. The result set in P is the location of the first - -- character of the following line (after skipping the sequence of line - -- terminator characters terminating the current line). In addition, if - -- the terminator sequence ends a physical line (the definition of what - -- constitutes a physical line is embodied in the implementation of this - -- function), and it is the first time this sequence is encountered, then - -- an entry is made in the lines table to record the location for further - -- use by functions such as Get_Line_Number. Physical is set to True if - -- the line terminator was the end of a physical line. + -- On entry, P points to a line terminator that has been encountered, + -- which is one of FF,LF,VT,CR or a wide character sequence whose value is + -- in category Separator,Line or Separator,Paragraph. The purpose of this + -- P points just past the character that was scanned. The purpose of this + -- routine is to distinguish physical and logical line endings. A physical + -- line ending is one of: + -- + -- CR on its own (MAC System 7) + -- LF on its own (Unix and unix-like systems) + -- CR/LF (DOS, Windows) + -- LF/CR (not used, but recognized in any case) + -- Wide character in Separator,Line or Separator,Paragraph category + -- + -- A logical line ending (that is not a physical line ending) is one of: + -- + -- VT on its own + -- FF on its own + -- + -- On return, P is bumped past the line ending sequence (one of the above + -- seven possibilities). Physical is set to True to indicate that a + -- physical end of line was encountered, in which case this routine also + -- makes sure that the lines table for the current source file has an + -- appropriate entry for the start of the new physical line. function Source_Offset (S : Source_Ptr) return Nat; -- Returns the zero-origin offset of the given source location from the |