Plutarch functions are strict

All Plutarch functions are strict. When you apply a Plutarch function to an argument using papp (or #/#$ - synonyms to papp) - the argument will be evaluated before being passed into to the function. If you don’t want the argument to be evaluated, you can use pdelay.

See: Delay and Force.

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Using Haskell level functions

There is one simple and straightforward use case though, when you want a function argument to be lazily evaluated. In such a case, you should use a Haskell level function that pdelays the argument before calling some Plutarch level function. Recall that Plutarch level functions are strict.
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Plutarch functions are strict
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Plutarch functions are strict