closures.md

Closures in TechScript

Closures are functions that capture and retain variables from their enclosing lexical scope.

---

🏗️ Capturing State

When a function is declared inside an outer function, the inner function retains access to the outer function's variables:

to create_counter(start_val):
    count is start_val
    
    to next_val():
        count becomes count + 1
        return count
        
    return next_val

counter is create_counter(10)
say "Count 1: {counter()}" # 11
say "Count 2: {counter()}" # 12

In this example, the variable count is captured and retained by next_val across invocations.

---

🧬 Capture Dynamics

Captured variables maintain their state across executions:

to build_multiplier(factor):
    to multiply(value):
        return value * factor
    return multiply

triple is build_multiplier(3)
say "Triple 10: {triple(10)}" # 30