11.3.1.2 Haskell's latency calculation policy, 11.3.1.2haskell

11.3.1.2 Haskell's latency calculation policy, 11.3.1.2haskell

11.3.1.2 Haskell latency calculation Policy

 

In lazy evaluation strategy, the parameter value of the function is not calculated during function calling until it is used later. Let's go back to the previous example:

 

TestAndCalculate (Calculate (10 ));

 

Haskell jumps directly to the subject of the TestAndCalculate function. Haskell remembers that the name of the parameter value is num. If num is required later, Calculate (10) is run. Then, continue to run the command to obtain the result of TestCondition. If this function returns true, it indicates that the value of num is required, and Calculate (10) is executed. If TestCondition returns false, the Calculate function is not called at all.