The prefix of the Library_Level must now be an entity name, and the
attribute indicates if the entity is declarated at the library level.
Note that within a generic instantition, the name of the generic unit
denotes the instance, which means that this attribute can be used to
test if a generic is instantiated at the library level, as in:
1. generic
2. package LLTestP is
3. pragma Compile_Time_Warning
4. (not LLTestP'Library_Level,
5. "LLTest should be instantiated at library level");
6. end;
1. with LLTestP;
2. package LLTestP1 is
3. package P is new LLTestP;
4. XXX : Integer;
5. P1L : constant Boolean := XXX'Library_Level;
6. end;
1. with LLTestP;
2. with LLTestP1; use LLTestP1;
3. with Text_IO; use Text_IO;
4. procedure LLTest is
5. package P1 is new LLTestP;
|
>>> warning: in instantiation at lltestp.ads:4
>>> warning: LLTest should be instantiated at library level
6. X : Integer;
|
>>> warning: variable "X" is read but never assigned
7. begin
8. Put_Line (Boolean'Image (LLTest'Library_Level));
9. Put_Line (Boolean'Image (P1L));
10. Put_Line (Boolean'Image (X'Library_Level));
11. end;
When executed, the output is:
TRUE
TRUE
FALSE
Tested on x86_64-pc-linux-gnu, committed on trunk
2013-10-14 Robert Dewar <de...@adacore.com>
* gnat_rm.texi: Library_Level attribute now applies to an
entity name.
* sem_attr.adb (Analyze_Attribute, case Library_Level): Prefix
is now an entity name.
Index: gnat_rm.texi
===================================================================
--- gnat_rm.texi (revision 203528)
+++ gnat_rm.texi (working copy)
@@ -8348,21 +8348,20 @@
@findex Library_Level
@noindent
@noindent
-@code{Standard'Library_Level} (@code{Standard} is the only allowed
-prefix) returns a Boolean value which is True if the attribute is
-evaluated at the library level (e.g. with a package declaration),
-and false if evaluated elsewhere (e.g. within a subprogram body).
-In the case of generics, the value indicates the placement of
-the instantiation, not the template, and indeed the use of this
-attribute within a generic is the intended common application
-as shown in this example:
+@code{P'Library_Level}, where P is an entity name,
+returns a Boolean value which is True if the entity is declared
+at the library level, and False otherwise. Note that within a
+generic instantition, the name of the generic unit denotes the
+instance, which means that this attribute can be used to test
+if a generic is instantiated at the library level, as shown
+in this example:
@smallexample @c ada
generic
...
package Gen is
pragma Compile_Time_Error
- (not Standard'Library_Level,
+ (not Gen'Library_Level,
"Gen can only be instantiated at library level");
...
end Gen;
Index: sem_attr.adb
===================================================================
--- sem_attr.adb (revision 203528)
+++ sem_attr.adb (working copy)
@@ -3689,11 +3689,14 @@
when Attribute_Library_Level =>
Check_E0;
- Check_Standard_Prefix;
+ if not Is_Entity_Name (P) then
+ Error_Attr_P ("prefix of % attribute must be an entity name");
+ end if;
+
if not Inside_A_Generic then
Set_Boolean_Result (N,
- Nearest_Dynamic_Scope (Current_Scope) = Standard_Standard);
+ Is_Library_Level_Entity (Entity (P)));
end if;
Set_Etype (N, Standard_Boolean);
