c++ - MISRA 5-2-1规则需要后缀表达式吗？

Question

MISRA-2008中的规则5-2-1指出:

Each operand of a logical && or || shall be a postfix-expression. Exception: Where an expression consists of either a sequence of only logical && or a sequence of only logical ||, extra parentheses are not required.

以下是示例，直接来自文档本身:

if (x == 0 && ishigh)      // Non-compliant
if (( x == 0 ) && ishigh)  // Compliant
if (x || y || z)           // Compliant by exception, if x, y and z bool
if (x || y && z)           // Non-compliant
if (x || (y && z))         // Compliant
if (x && !y)               // Non-compliant
if (x && (!y))             // Compliant
if (is_odd(y) && x)        // Compliant
if ((x > c1) && (y > c2)  && (z > c3))   // Compliant - exception
if ((x > c1) && (y > c2)  || (z > c3))   // Non-compliant
if ((x > c1) && ((y > c2) || (z > c3)))  // Compliant as extra() used

有人可以指出我 posfix -表达式在哪里吗？他们看起来像主要的。我看不到++或--之类的东西。

Answer 1

所有的主表达式都是后缀表达式。在这些示例中，唯一不是主表达式的postfix-expression是is_odd(y)。
后缀表达式的grammar为:

postfix-expression:

primary-expression
postfix-expression [ expr-or-braced-init-list ]
postfix-expression ( expression-listopt )
simple-type-specifier ( expression-listopt )
typename-specifier ( expression-listopt )
simple-type-specifier braced-init-list
typename-specifier braced-init-list
postfix-expression . templateopt id-expression
postfix-expression -> templateopt id-expression
postfix-expression ++
postfix-expression --
dynamic_­cast < type-id > ( expression )
static_­cast < type-id > ( expression )
reinterpret_­cast < type-id > ( expression )
const_­cast < type-id > ( expression )
typeid ( expression )
typeid ( type-id )

和

primary-expression:

literal
this
( expression )
id-expression
lambda-expression
fold-expression
requires-expression