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> Implementing a basic "useState" and "runFunctionComponent" is easier than most third-semester CS assignments. I'm not sure it is. There is a global dispatche

by spion 2y ago

> Implementing a basic "useState" and "runFunctionComponent" is easier than most third-semester CS assignments. I'm not sure it is. There is a global dispatcher that finds the right component state to use and increments a counter to ensure that the correct state "slot" for that component is used. There are also a bunch of mechanisms to prevent slot mismatches. I guess you could make a loose analogy with writing custom allocators, except instead of the binding knowing the address, the order of calling useState determines the address :) Really not that simple.

chmod775 2y ago
> I'm not sure it is. There is a global dispatcher that finds the right component state to use and increments a counter to ensure that the correct state "slot" for that component is used. Explicitly not part of that proposed task. We're talking about a basic hooks implementation with useState here, not how react deals with its tree of components. For the sake of the task the signature of runFunctionComponent just needs to be runFunctionComponent<P, R>(fc: (props: P) => R, props: P, hooks?: any[]): { hooks: any[], returnValue: R } or even dumbed down to runWithHooks(runFC: () => void, hooks?: any[]): any[] where runFC would wrap the call to the function component to pass the appropriate props and store the return value, freeing students from thinking about that. Also specify the function doesn't need to be re-entrant. In either case it won't need concern itself with what the component returns (children, whatever), matching children to tree nodes, or scheduling, at all. Would be nonsense to cram that logic in there anyhow. What you were talking about would make a good later task: easy to get a basic implementation, but hard to get an implementation that isn't subtly wrong in some way. Plus you can slap on extra goals like supporting keys. Lots of room to score students beyond just pass/fail.

by spion 2y ago

chmod775 2y ago

> I'm not sure it is. There is a global dispatcher that finds the right component state to use and increments a counter to ensure that the correct state "slot" for that component is used. Explicitly not part of that proposed task. We're talking about a basic hooks implementation with useState here, not how react deals with its tree of components. For the sake of the task the signature of runFunctionComponent just needs to be runFunctionComponent<P, R>(fc: (props: P) => R, props: P, hooks?: any[]): { hooks: any[], returnValue: R } or even dumbed down to runWithHooks(runFC: () => void, hooks?: any[]): any[] where runFC would wrap the call to the function component to pass the appropriate props and store the return value, freeing students from thinking about that. Also specify the function doesn't need to be re-entrant. In either case it won't need concern itself with what the component returns (children, whatever), matching children to tree nodes, or scheduling, at all. Would be nonsense to cram that logic in there anyhow. What you were talking about would make a good later task: easy to get a basic implementation, but hard to get an implementation that isn't subtly wrong in some way. Plus you can slap on extra goals like supporting keys. Lots of room to score students beyond just pass/fail.