How do I make light in hand while holding certain items?

[HackerDragon9999]

For example, when holding a torch, you act as a light source.

 

[Teacat1]

optifine dynamic lighting OR setblock light (/i get light)

 

[ARMcPro]

The main idea of making one is, displaying a light block in your eye location (if the block is air), and removing it when you walk away from that place or when you unhold the item;

to do it, you would want in a loop to display an air block in the old location; then display a light in the new location and setting the old location to the new one if the player is holding the item