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1

[{*precedence of operators*}
{*operator precedence*}
The language defines the following six categories
of operators (given in order of increasing precedence). The corresponding
operator_symbols, and only those,
can be used as designators in declarations
of functions for user-defined operators. See 6.6,
``Overloading of Operators''.]

2

3

4

5

6

7

7.a

8

For a sequence of operators of the same precedence
level, the operators are associated with their operands in textual order
from left to right. Parentheses can be used to impose specific associations.

8.a

8.b

See the Implementation Permissions
below regarding flexibility in reassociating operators of the same precedence.

9

{*predefined operator*}
{*operator (predefined)*}
For each form of type definition, certain of the
above operators are *predefined*; that is, they are implicitly declared
immediately after the type definition. {*binary operator*}
{*operator (binary)*}
{*unary operator*} {*operator
(unary)*} For each such implicit operator
declaration, the parameters are called Left and Right for *binary*
operators; the single parameter is called Right for *unary* operators.
[An expression of the form X op Y, where op is a binary operator, is
equivalent to a function_call of
the form "op"(X, Y). An expression of the form op Y, where
op is a unary operator, is equivalent to a function_call
of the form "op"(Y). The predefined operators and their effects
are described in subclauses 4.5.1 through
4.5.6.]

10

[{*Constraint_Error (raised
by failure of run-time check)*} The predefined
operations on integer types either yield the mathematically correct result
or raise the exception Constraint_Error. For implementations that support
the Numerics Annex, the predefined operations on real types yield results
whose accuracy is defined in Annex G, or raise
the exception Constraint_Error. ]

10.a

11

{*Constraint_Error (raised
by failure of run-time check)*} The implementation
of a predefined operator that delivers a result of an integer or fixed
point type may raise Constraint_Error only if the result is outside the
base range of the result type.

12

{*Constraint_Error (raised
by failure of run-time check)*} The implementation
of a predefined operator that delivers a result of a floating point type
may raise Constraint_Error only if the result is outside the safe range
of the result type.

12.a

13

For a sequence of predefined operators of the
same precedence level (and in the absence of parentheses imposing a specific
association), an implementation may impose any association of the operators
with operands so long as the result produced is an allowed result for
the left-to-right association, but ignoring the potential for failure
of language-defined checks in either the left-to-right or chosen order
of association.

13.a

13.b

Note that this permission does
not apply to user-defined operators.

NOTES

14

11 The two operands of
an expression of the form X op Y, where op is a binary operator, are
evaluated in an arbitrary order, as for any function_call
(see 6.4).

15

16

X > 4.0

17

Y**(-3)

A / B * C

A + (B + C)

17.a

We don't give a detailed definition
of precedence, since it is all implicit in the syntax rules anyway.

17.b

The permission to reassociate
is moved here from RM83-11.6(5), so it is closer to the rules defining
operator association.