1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 2011, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 -- This package provides support for numerical systems with dimensions. A
27 -- "dimension" is a compile-time property of a numerical type which represents
28 -- a relation between various quantifiers such as length, velocity, etc.
30 -- Package System.Dim_Mks offers a ready-to-use system of SI base units. In
31 -- addition, the implementation of this feature offers the ability to define
32 -- an arbitrary system of units through the use of Ada 2012 aspects.
34 -- Dimensionality checking is part of type analysis performed by the compiler.
35 -- It ensures that manipulation of quantified numeric values is sensible with
36 -- respect to the system of units.
38 -----------------------------
39 -- Aspect_Dimension_System --
40 -----------------------------
42 -- In order to enable the user to create their own dimension system, a new
43 -- aspect: Aspect_Dimension_System has been created.
45 -- Note that this aspect applies for type declaration of type derived from any
48 -- It defines the names of each dimension
50 ----------------------
51 -- Aspect_Dimension --
52 ----------------------
54 -- This new aspect applies for subtype and object declarations in order to
55 -- define new dimensions.
57 -- Using this aspect, the user is able to create new subtype/object with any
60 -- Note that the base type of the subtype/object must be the type that defines
61 -- the corresponding dimension system.
63 -- The expression of this aspect is an aggregate of rational values for each
64 -- dimension in the corresponding dimension system.
66 -------------------------------------------
67 -- Dimensionality checking & propagation --
68 -------------------------------------------
70 -- For each node (when needed), a dimension analysis (Analyze_Dimension) is
71 -- performed as part of the Resolution routine or the Analysis routine if no
74 -- The dimension analysis is divided into two phases:
76 -- Phase 1: dimension checking
78 -- Phase 2: propagation of dimensions
80 -- Depending on the node kind, either none, one phase or two phases are
83 -- Phase 2 is called only when the node allows a dimension (see body of
84 -- Sem_Dim to get the list of nodes that permit dimensions).
90 -- This section contains the routine used for IO purposes
92 with Types; use Types;
96 procedure Analyze_Aspect_Dimension
100 -- Analyze the contents of aspect Dimension. Associate the provided values
101 -- and quantifiers with the related context N. Id is the corresponding
102 -- Aspect_Id (Aspect_Dimension) Aggr is the corresponding expression for
103 -- the aspect Dimension declared by the declaration of N.
105 procedure Analyze_Aspect_Dimension_System
109 -- Analyze the contents of aspect Dimension_System. Extract the numerical
110 -- type, unit name and corresponding symbol from each indivitual dimension.
111 -- Id is the corresponding Aspect_Id (Aspect_Dimension_System)
112 -- Aggr is the corresponding expression for the aspect Dimension_System
113 -- declared by the declaration of N.
115 procedure Analyze_Dimension (N : Node_Id);
116 -- N may denote any of the following contexts:
117 -- * assignment statement
118 -- * attribute reference
120 -- * compontent declaration
121 -- * extended return statement
124 -- * indexed component
125 -- * object declaration
126 -- * object renaming declaration
127 -- * qualified expression
128 -- * selected component
129 -- * simple return statement
131 -- * subtype declaration
134 -- * unchecked type conversion
135 -- Depending on the context, ensure that all expressions and entities
136 -- involved do not violate the rules of a system.
138 procedure Eval_Op_Expon_For_Dimensioned_Type
141 -- Evaluate the Expon operator for dimensioned type with rational exponent.
142 -- Indeed the regular Eval_Op_Expon routine (see package Sem_Eval) is
143 -- restricted to Integer exponent. This routine deals only with rational
144 -- exponent which is not an integer if Btyp is a dimensioned type.
146 procedure Expand_Put_Call_With_Dimension_Symbol (N : Node_Id);
147 -- Determine whether N denotes a subprogram call to one of the routines
148 -- defined in System.Dim_Float_IO or System.Dim_Integer_IO and add an
149 -- extra actual to the call to represent the symbolic representation of
152 function Has_Dimension_System (Typ : Entity_Id) return Boolean;
153 -- Return True if type Typ has aspect Dimension_System applied to it
155 function Is_Dim_IO_Package_Instantiation (N : Node_Id) return Boolean;
156 -- Return True if N is a package instantiation of System.Dim_Integer_IO or
157 -- of System.Dim_Float_IO.
159 procedure Remove_Dimension_In_Call (Call : Node_Id);
160 -- Remove the dimensions from all formal parameters of Call
162 procedure Remove_Dimension_In_Statement (Stmt : Node_Id);
163 -- Remove the dimensions associated with Stmt