1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
/* n_27.t: Rescanning of a macro replace any macro call in the replacement
text after substitution of parameters by pre-expanded-arguments. This
re-examination may involve the succeding sequences from the source
file (what a queer thing!). */
/* 27.1: Cascaded use of object-like macros. */
/* 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8; */
#define NEST8 NEST7 + 8
#define NEST7 NEST6 + 7
#define NEST6 NEST5 + 6
#define NEST5 NEST4 + 5
#define NEST4 NEST3 + 4
#define NEST3 NEST2 + 3
#define NEST2 NEST1 + 2
#define NEST1 1
NEST8;
/* 27.2: Cascaded use of function-like macros. */
/* (1) + (1 + 2) + 1 + 2 + 1 + 2 + 3 + 1 + 2 + 3 + 4; */
#define FUNC4( a, b) FUNC3( a, b) + NEST4
#define FUNC3( a, b) FUNC2( a, b) + NEST3
#define FUNC2( a, b) FUNC1( a, b) + NEST2
#define FUNC1( a, b) (a) + (b)
FUNC4( NEST1, NEST2);
/* 27.3: An identifier generated by ## operator is subject to expansion. */
/* 1; */
#define glue( a, b) a ## b
#define MACRO_1 1
glue( MACRO_, 1);
#define sub( x, y) (x - y)
#define head sub(
#define math( op, a, b) op( (a), (b))
/* 27.4: 'sub' as an argument of math() is not pre-expanded, since '(' is
missing. */
/* ((a) - (b)); */
math( sub, a, b);
/* 27.5: Queer thing. */
/* (a - b); */
head a,b );
/* 27.6: Recursive macro (the 2nd 'm' is expanded to 'n' since it is in
source file). */
/* n; */
#define m n
#define n( a) a
m( m);
|
