Programming

Basics about programming

Stackful vs Stackless Coroutine

A coroutine is a function that can be paused and resumed later. Two main principles exists to save the states: stackless and stackful.

In contrast to a stackless coroutine a stackful coroutine can be suspended from within a nested stackframe. Execution resumes at exactly the same point in the code where it was suspended before. With a stackless coroutine, only the top-level routine may be suspended. Any routine called by that top-level routine may not itself suspend. This prohibits providing suspend/resume operations in routines within a general-purpose library.

source

To boil it down to a very simplistic definition, a stackful coroutine model would let you suspend or yield from anywhere. A stackless model is restricted to suspending only from inside coroutines, but the benefit is that it is lighter weight. Also, it's probably more feasible to retrofit to an existing language.

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See also technical explanation

Callback

Callback((fonction de rappel en francais)) is a function passing by parameter of another function.

See this example from wikipedia:

#include `<stdio.h>`
#include `<stdlib.h>`

/* The calling function takes a single callback as a parameter. */
void PrintTwoNumbers(int (*numberSource)(void)) {
    printf("%d and %d\n", numberSource(), numberSource());
}

/* A possible callback */
int overNineThousand(void) {
    return (rand() % 1000) + 9001;
}

/* Another possible callback. */
int meaningOfLife(void) {
    return 42;
}

/* Here we call PrintTwoNumbers() with three different callbacks. */
int main(void) {
    PrintTwoNumbers(&rand);
    PrintTwoNumbers(&overNineThousand);
    PrintTwoNumbers(&meaningOfLife);
    return 0;
}

Loop

Pass one time the loop:

#include `<stdio.h>`

int main(){
 int i=0;
 for(; i<4; i++)
 {
  if(i==2){
   continue; // NOTE this instruction
  }

  printf("%d, ", i);
 }

 return 0;
}

Output: 0, 1, 3,

Pass all loop:

#include `<stdio.h>`

int main(){
 int i=0;
 for(; i<4; i++)
 {
  if(i==2){
   break; // NOTE this instruction
  }

  printf("%d, ", i);
 }

 return 0;
}

Output: 0, 1,