我有一段代码，但是我无法理解它。
在将pow2s的g替换为map的gen结构之后，我陷入了困境。从那里开始，我无法看到它如何继续跟踪该值以及如何存储该值。
该代码可以编译和运行。
有人可以帮助我理解这段代码吗？谢谢！
PS：我正在学习C语言。
以下是需要翻译的Python代码：
>>> def pow2s():
yield 1
for i in map((lambda x:2*x),pow2s()):
yield i
>>> def mymap(f,iter):
for i in iter:
yield f(i)
翻译后的C代码：
#include <stdio.h>
#include <stdlib.h>
struct gen { // generic structure, the base of all generators
int (*next)() ;
int continue_from ;
} ;
typedef int (*fptr)() ;
// Each iterator has 3 components: a structure, a constructor for the structure,
// and a next function
// map
struct mapgen { // structure for map
int (*next)() ;
int continue_from ; // not really required, provided for compatibility
fptr f ;
struct gen *g ;
} ;
int map_next(struct mapgen *p) { // next function for map
return p->f(p->g->next(p->g)) ;
}
struct gen *map(fptr f, struct gen *g) { // constructor for map iterator
struct mapgen *p = (struct mapgen *)malloc(sizeof(struct mapgen));
p->next = map_next;
p->continue_from = 0;
p->f = f;
p->g = g;
return (struct gen *)p ;
}
// powers of 2
struct pow2s { // structure
int (*next)() ;
int continue_from ;
struct gen *g ;
};
int times2(int x) { // anonymous lambda is translated into this
return 2*x ;
}
struct gen *pow2() ; // forward declaration of constructor
int pow2next(struct pow2s * p){ // next function for iterator
switch(p->continue_from) {
case 0:
p->continue_from = 1;
return 1;
case 1:
p->g = map(times2,pow2()) ;
p->continue_from = 2;
return p->g->next(p->g) ;
case 2:
p->continue_from = 2;
return p->g->next(p->g) ;
}
}
struct gen * pow2() { // constructor for pow2
struct pow2s * p = (struct pow2s *)malloc(sizeof(struct pow2s));
p->next = pow2next;
p->continue_from = 0;
return (struct gen *)p;
}
// in main, create an iterator and print some of its elements.
int main() {
int i ;
struct gen * p = pow2() ;
for(i=0;i<10;i++)
printf("%d ",p->next(p)) ;
printf("\n");
}