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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S C N . N L I T --
-- --
-- B o d y --
-- --
-- $Revision: 1.32 $ --
-- --
-- Copyright (C) 1992,1993,1994,1995,1996 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- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
with Uintp; use Uintp;
with Urealp; use Urealp;
separate (Scn)
procedure Nlit is
C : Character;
-- Current source program character
Base_Char : Character;
-- Either # or : (character at start of based number)
Base : Int;
-- Value of base
UI_Base : Uint;
-- Value of base in Uint format
UI_Int_Value : Uint;
-- Value of integer scanned by Scan_Integer in Uint format
UI_Num_Value : Uint;
-- Value of integer in numeric value being scanned
Scale : Int;
-- Scale value for real literal
UI_Scale : Uint;
-- Scale in Uint format
Exponent_Is_Negative : Boolean;
-- Set true for negative exponent
Extended_Digit_Value : Int;
-- Extended digit value
Point_Scanned : Boolean;
-- Flag for decimal point scanned in numeric literal
-----------------------
-- Local Subprograms --
-----------------------
procedure Error_Digit_Expected;
-- Signal error of bad digit, Scan_Ptr points to the location at which
-- the digit was expected on input, and is unchanged on return.
procedure Scan_Integer;
-- Procedure to scan integer literal. On entry, Scan_Ptr points to a
-- digit, on exit Scan_Ptr points past the last character of the integer.
-- For each digit encountered, UI_Int_Value is multiplied by 10, and the
-- value of the digit added to the result. In addition, the value in
-- Scale is decremented by one for each actual digit scanned.
--------------------------
-- Error_Digit_Expected --
--------------------------
procedure Error_Digit_Expected is
begin
Error_Msg_S ("digit expected");
end Error_Digit_Expected;
-------------------
-- Scan_Integer --
-------------------
procedure Scan_Integer is
C : Character;
-- Next character scanned
begin
C := Source (Scan_Ptr);
-- Loop through digits (allowing underlines)
loop
Accumulate_Checksum (C);
UI_Int_Value :=
UI_Int_Value * 10 + (Character'Pos (C) - Character'Pos ('0'));
Scan_Ptr := Scan_Ptr + 1;
Scale := Scale - 1;
C := Source (Scan_Ptr);
if C = '_' then
Accumulate_Checksum ('_');
loop
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
exit when C /= '_';
Error_No_Double_Underline;
end loop;
if C not in '0' .. '9' then
Error_Digit_Expected;
exit;
end if;
else
exit when C not in '0' .. '9';
end if;
end loop;
end Scan_Integer;
----------------------------------
-- Start of Processing for Nlit --
----------------------------------
begin
Base := 10;
UI_Base := Uint_10;
UI_Int_Value := Uint_0;
Scale := 0;
Scan_Integer;
Scale := 0;
Point_Scanned := False;
UI_Num_Value := UI_Int_Value;
-- Various possibilities now for continuing the literal are
-- period, E/e (for exponent), or :/# (for based literal).
Scale := 0;
C := Source (Scan_Ptr);
if C = '.' then
-- Scan out point, but do not scan past .. which is a range sequence,
-- and must not be eaten up scanning a numeric literal.
while C = '.' and then Source (Scan_Ptr + 1) /= '.' loop
Accumulate_Checksum ('.');
if Point_Scanned then
Error_Msg_S ("duplicate point ignored");
end if;
Point_Scanned := True;
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
if C not in '0' .. '9' then
Error_Msg ("real literal cannot end with point", Scan_Ptr - 1);
else
Scan_Integer;
UI_Num_Value := UI_Int_Value;
end if;
end loop;
-- Based literal case. The base is the value we already scanned.
-- In the case of colon, we insist that the following character
-- is indeed an extended digit or a period. This catches a number
-- of common errors, as well as catching the well known tricky
-- bug otherwise arising from "x : integer range 1 .. 10:= 6;"
elsif C = '#'
or else (C = ':' and then
(Source (Scan_Ptr + 1) = '.'
or else
Source (Scan_Ptr + 1) in '0' .. '9'
or else
Source (Scan_Ptr + 1) in 'A' .. 'Z'
or else
Source (Scan_Ptr + 1) in 'a' .. 'z'))
then
Accumulate_Checksum (C);
Base_Char := C;
UI_Base := UI_Int_Value;
if UI_Base < 2 or else UI_Base > 16 then
Error_Msg_SC ("base not 2-16");
UI_Base := Uint_16;
end if;
Base := UI_To_Int (UI_Base);
Scan_Ptr := Scan_Ptr + 1;
-- Scan out extended integer [. integer]
C := Source (Scan_Ptr);
UI_Int_Value := Uint_0;
Scale := 0;
loop
if C in '0' .. '9' then
Accumulate_Checksum (C);
Extended_Digit_Value :=
Int'(Character'Pos (C)) - Int'(Character'Pos ('0'));
elsif C in 'A' .. 'F' then
Accumulate_Checksum (Character'Val (Character'Pos (C) + 32));
Extended_Digit_Value :=
Int'(Character'Pos (C)) - Int'(Character'Pos ('A')) + 10;
elsif C in 'a' .. 'f' then
Accumulate_Checksum (C);
Extended_Digit_Value :=
Int'(Character'Pos (C)) - Int'(Character'Pos ('a')) + 10;
else
Error_Msg_S ("extended digit expected");
exit;
end if;
if Extended_Digit_Value >= Base then
Error_Msg_S ("digit >= base");
end if;
UI_Int_Value := UI_Int_Value * UI_Base + Extended_Digit_Value;
Scale := Scale - 1;
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
if C = '_' then
loop
Accumulate_Checksum ('_');
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
exit when C /= '_';
Error_No_Double_Underline;
end loop;
elsif C = '.' then
Accumulate_Checksum ('.');
if Point_Scanned then
Error_Msg_S ("duplicate point ignored");
end if;
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
Point_Scanned := True;
Scale := 0;
elsif C = Base_Char then
Accumulate_Checksum (C);
Scan_Ptr := Scan_Ptr + 1;
exit;
elsif C = '#' or else C = ':' then
Error_Msg_S ("based number delimiters must match");
Scan_Ptr := Scan_Ptr + 1;
exit;
elsif not Identifier_Char (C) then
if Base_Char = '#' then
Error_Msg_S ("missing '#");
else
Error_Msg_S ("missing ':");
end if;
exit;
end if;
end loop;
UI_Num_Value := UI_Int_Value;
end if;
-- Scan out exponent
if not Point_Scanned then
Scale := 0;
UI_Scale := Uint_0;
else
UI_Scale := UI_From_Int (Scale);
end if;
if Source (Scan_Ptr) = 'e' or else Source (Scan_Ptr) = 'E' then
Accumulate_Checksum ('e');
Scan_Ptr := Scan_Ptr + 1;
Exponent_Is_Negative := False;
if Source (Scan_Ptr) = '+' then
Accumulate_Checksum ('+');
Scan_Ptr := Scan_Ptr + 1;
elsif Source (Scan_Ptr) = '-' then
Accumulate_Checksum ('-');
if not Point_Scanned then
Error_Msg_S ("negative exponent not allowed for integer literal");
else
Exponent_Is_Negative := True;
end if;
Scan_Ptr := Scan_Ptr + 1;
end if;
UI_Int_Value := Uint_0;
if Source (Scan_Ptr) in '0' .. '9' then
Scan_Integer;
else
Error_Digit_Expected;
end if;
if Exponent_Is_Negative then
UI_Scale := UI_Scale - UI_Int_Value;
else
UI_Scale := UI_Scale + UI_Int_Value;
end if;
end if;
-- Case of real literal to be returned
if Point_Scanned then
Token := Tok_Real_Literal;
Token_Node := New_Node (N_Real_Literal, Token_Ptr);
Set_Realval (Token_Node,
UR_From_Components (
Num => UI_Num_Value,
Den => -UI_Scale,
Rbase => Base));
-- Case of integer literal to be returned
else
Token := Tok_Integer_Literal;
Token_Node := New_Node (N_Integer_Literal, Token_Ptr);
if UI_Scale = 0 then
Set_Intval (Token_Node, UI_Num_Value);
-- Avoid doing possibly expensive calculations in cases like
-- parsing 163E800_000# when semantics will not be done anyway.
-- This is especially useful when parsing garbled input.
elsif Operating_Mode /= Check_Syntax
and then (Errors_Detected = 0 or else Try_Semantics)
then
Set_Intval (Token_Node, UI_Num_Value * UI_Base ** UI_Scale);
else
Set_Intval (Token_Node, No_Uint);
end if;
end if;
return;
end Nlit;
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