10.3.6 Attributes

A project (and its packages) may have attributes that define the project's properties. Some attributes have values that are strings; others have values that are string lists.

There are two categories of attributes: simple attributes and associative arrays (see Associative Array Attributes).

The names of the attributes are restricted; there is a list of project attributes, and a list of package attributes for each package. The names are not case sensitive.

The project attributes are as follows (all are simple attributes):

Attribute Name	Value
Source_Files	string list
Source_Dirs	string list
Source_List_File	string
Object_Dir	string
Exec_Dir	string
Main	string list
Languages	string list
Library_Dir	string
Library_Name	string
Library_Kind	string
Library_Elaboration	string
Library_Version	string

The attributes for package Naming are as follows (see Naming Schemes):

Attribute Name	Category	Index	Value
Specification_Suffix	associative array	language name	string
Implementation_Suffix	associative array	language name	string
Separate_Suffix	simple attribute	n/a	string
Casing	simple attribute	n/a	string
Dot_Replacement	simple attribute	n/a	string
Specification	associative array	Ada unit name	string
Implementation	associative array	Ada unit name	string
Specification_Exceptions	associative array	language name	string list
Implementation_Exceptions	associative array	language name	string list

The attributes for package Builder, Compiler, Binder, Linker, Cross_Reference, and Finder are as follows (see Switches and Project Files).

Attribute Name	Category	Index	Value
Default_Switches	associative array	language name	string list
Switches	associative array	file name	string list

In addition, package Builder has a single string attribute Local_Configuration_Pragmas and package Builder has a single string attribute Global_Configuration_Pragmas.

The attribute for package Glide are not documented: they are for internal use only.

Each simple attribute has a default value: the empty string (for string-valued attributes) and the empty list (for string list-valued attributes).

Similar to variable declarations, an attribute declaration defines a new value for an attribute.

Examples of simple attribute declarations:

        for Object_Dir use "objects";
        for Source_Dirs use ("units", "test/drivers");

A simple attribute declaration starts with the reserved word for, followed by the name of the attribute, followed by the reserved word use, followed by an expression (whose kind depends on the attribute), followed by a semicolon.

Attributes may be referenced in expressions. The general form for such a reference is <entity>'<attribute>: the entity for which the attribute is defined, followed by an apostrophe, followed by the name of the attribute. For associative array attributes, a litteral string between parentheses need to be supplied as index.

Examples are:

       project'Object_Dir
       Naming'Dot_Replacement
       Imported_Project'Source_Dirs
       Imported_Project.Naming'Casing
       Builder'Default_Switches("Ada")

The entity may be:

• project for an attribute of the current project
• The name of an existing package of the current project
• The name of an imported project
• The name of a parent project (extended by the current project)
• An imported/parent project name, followed by a dot, followed by a package name

Example:

        project Prj is
          for Source_Dirs use project'Source_Dirs & "units";
          for Source_Dirs use project'Source_Dirs & "test/drivers"
        end Prj;

In the first attribute declaration, initially the attribute Source_Dirs has the default value: an empty string list. After this declaration, Source_Dirs is a string list of one element: "units". After the second attribute declaration Source_Dirs is a string list of two elements: "units" and "test/drivers".

Note: this example is for illustration only. In practice, the project file would contain only one attribute declaration:

        for Source_Dirs use ("units", "test/drivers");