call-by-name

As you can surmise from the fact that it has a name, it is not some newfangled shiny toy idea, it goes back to ALGOL 60, where it was known as call-by-name.

raganwald 2009

One thing that's interesting to notice about this strategy is that it seems stricter than call-by-name.

Planet Haskell 2009

For that reason, I prefer call-by-name semantics when an expression is not meant to be persisted beyond the function invocation.

raganwald 2009

We could argue that since our call-by-name functions have different behaviour than ordinary functions or methods, they ought to have different syntax.

raganwald 2009

As is standard with the rewrite gem, only the code in the do ... end block is affected by your change. call-by-name, in summary

raganwald 2009

But it feels like a move in an interesting direction: if it is a win to sometimes meta-program Ruby's syntax with DSLs, it ought to also be a win to sometimes meta-program Ruby's semantics with call-by-name functions.

raganwald 2009

The application of call-by-name as a substitute for full-blown macros isn't novel either.

raganwald 2009

Caching of this sort is what distinguishes call-by-need from call-by-name and allows lazy evaluation to work efficiently for data representations.

Planet Haskell 2009

Functions with call-by-name semantics communicate the same thing as blocks: The expressions are to be consumed by the function.

raganwald 2009

You can write your own functions with call-by-name semantics using called_by_name just as you see here.

raganwald 2009