v4 Control Flow

Why control flow now?

• expressions are not enough
• loops require jump topology and branch patching

for-loop model

• execute init once
• evaluate cond before each body pass
• body -> post -> cond
• break and continue are loop-specific edges

Scope rule

• loop init scope covers cond/body/post
• scope exits with loop

Short-circuit lowering

• && skips RHS on falsey LHS
• || skips RHS on truthy LHS
• use boolean result semantics for expression value

patching discipline

• track loop metadata on a stack
• patch break -> loop end
• patch continue -> post/next-iteration point

Correctness checks

• every conditional or logical jump target patched
• nested loops resolve to nearest loop
• precedence: && above ||

Checks to verify

• false && sideEffect() does not call sideEffect
• true || sideEffect() does not call sideEffect
• explicit break exits only current loop