--          This file is part of SmallEiffel The GNU Eiffel Compiler.
--          Copyright (C) 1994-98 LORIA - UHP - CRIN - INRIA - FRANCE
--            Dominique COLNET and Suzanne COLLIN - colnet@loria.fr 
--                       http://www.loria.fr/SmallEiffel
-- SmallEiffel is  free  software;  you can  redistribute it and/or modify it 
-- under the terms of the GNU General Public License as published by the Free
-- Software  Foundation;  either  version  2, or (at your option)  any  later 
-- version. SmallEiffel is distributed in the hope that it will be useful,but
-- WITHOUT 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  along  with  SmallEiffel;  see the file COPYING.  If not,
-- write to the  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-- Boston, MA 02111-1307, USA.
--
class ASSERTION
   -- 
   -- To store one assertion. 
   --
   
inherit GLOBALS;
   
creation make
   
feature 
   
   tag: TAG_NAME;
   
   expression: EXPRESSION;
   
   comment: COMMENT;
   
   current_type: TYPE;
   
feature {NONE}
   
   make(t: like tag; exp: like expression; c: like comment) is
      require
	 t /= void or exp /= Void or c /= Void;
      do
	 tag := t;
	 expression := exp;
         comment := c;
      ensure	 
	 tag = t;
	 expression = exp;
         comment = c;
      end;
   
feature 
   
   start_position: POSITION is
      do
	 if tag /= Void then
	    Result := tag.start_position;
	 elseif expression /= Void then
	    Result := expression.start_position;
	 else
	    Result := comment.start_position;
	 end;
      end;
   
   pretty_print is
      require
	 fmt.indent_level >= 1;
      do
	 if tag /= Void then
	    fmt.put_string(tag.to_string);
	    fmt.put_string(": ");
	 end;
	 if expression /= Void then
	    expression.pretty_print;
	    if fmt.semi_colon_flag then
	       fmt.put_string("; ");
	    end;
	 end;
	 if comment /= Void then
	    comment.pretty_print;
	 end;
      end;
   
   short(h01,r01,h02,r02,h03,r03,h04,r04,h05,r05,h06,r06,h07,r07,
	 h08,r08,h09,r09,h10,r10,h11,r11,h12,r12,h13,r13: STRING) is
      do
	 short_print.hook_or(h01,r01);
	 if tag = Void then
	    short_print.hook_or(h02,r02);
	 else 
	    short_print.hook_or(h03,r03);
	    tag.short;
	    short_print.hook_or(h04,r04);
	 end;
	 if expression = Void then
	    short_print.hook_or(h05,r05);
	 else
	    short_print.hook_or(h06,r06);
	    expression.short;
	    short_print.hook_or(h07,r07);
	 end;
	 if comment = Void then
	    short_print.hook_or(h08,r08);
	 else
	    short_print.hook_or(h09,r09);
	    comment.short(h10,r10,h11,r11);
	    short_print.hook_or(h12,r12);
	 end;
	 short_print.hook_or(h13,r13);
      end;
   
   to_runnable(ct: TYPE): like Current is
      require
	 ct.is_run_type;
      local
	 e: like expression;
      do
	 if current_type = Void then
	    current_type := ct;
	    Result := Current;
	    if expression /= Void then
	       e := expression.to_runnable(ct);
	       if e = Void then
		  error(start_position,fz_bad_assertion);
	       else
		  expression := e;
		  if not expression.result_type.is_boolean then
		     eh.add_type(expression.result_type,fz_is_not_boolean);
		     error(start_position,fz_bad_assertion);
		  end;
	       end;
	    end;	 
	 else
	    !!Result.make(tag,expression,comment);
	    Result := Result.to_runnable(ct);
	 end;
      ensure
	 nb_errors = 0 implies Result.is_checked;
      end;
   
   is_checked: BOOLEAN is
      do
	 Result := current_type /= Void;
      end;
   
   use_current: BOOLEAN is
      do
	 if expression /= Void then
	    Result := expression.use_current;
	 end;
      end;
   
   afd_check is
      require
	 is_checked
      do
	 if expression /= Void then
	    expression.afd_check;
	 end;
      end;

   compile_to_c is
      require
	 is_checked
      do
	 if expression /= Void then
	    cpp.check_assertion(expression);
	 end;
      end;

   is_pre_computable: BOOLEAN is
      do
	 if expression = Void then
	    Result := true;
	 else
	    Result := expression.is_pre_computable;
	 end;
      end;

   is_always_true: BOOLEAN is
      do
	 if expression = Void then
	    Result := true;
	 elseif expression.is_static then
	    Result := expression.static_value = 1
	 end;
      end;

   c_declare_for_old is
      require
	 is_checked
      do
	 if expression /= Void then
	    expression.c_declare_for_old;
	 end;
      end;

   compile_to_c_old is
      require
	 is_checked
      do
	 if expression /= Void then
	    expression.compile_to_c_old;
	 end;
      end;

   compile_to_jvm_old is
      require
	 is_checked
      do
	 if expression /= Void then
	    expression.compile_to_jvm_old;
	 end;
      end;
   
feature {ASSERTION_LIST}

   compile_to_jvm(last_chance: BOOLEAN) is
	 -- The boolean result of the expression is pushed.
	 -- When `last_chance' is true, the generated code includes an
	 -- error message to be printed when assertion is false.
	 --
      require
	 is_checked
      local
	 point1: INTEGER;
	 ca: like code_attribute;
      do
	 ca := code_attribute;
	 if expression = Void then
	    ca.opcode_iconst_1;
	 else
	    expression.compile_to_jvm
	    if last_chance then
	       point1 := code_attribute.opcode_ifne;
	       ca.runtime_error(expression.start_position,Void,fz_50);
	       ca.resolve_u2_branch(point1);
	       ca.opcode_iconst_1;
	    end;
	 end;
      end;

feature {ASSERTION_LIST}

   collect_c_tmp is
      do
	 if expression /= Void then
	    expression.collect_c_tmp;
	 end;
      end;

feature {NONE}

   tmp_string: STRING is
      once
	 !!Result.make(128);
      end;

invariant
   
   tag /= Void or expression /= Void or comment /= Void;
   
end -- ASSERTION