Because of their modularity, pure functions are easy to reuse,test, parallelize.
Reading from a file is therefore not referentially transparent!įollowing the discipline of FP is tremendously beneficial because of the increase in modularity that we gain from programming with pure functions. Later we can discuss this with the concept of “ Referential Transparency ” (RT), This means you can substitute a function call and a given set of parameters with the result the function would return. This condition is not true in case of read and write operation, the output may change without changing arguments. Reading from a file or writing into itįor a pure functional program the same set of input parameters to a function always produce the same set of output. Well let us look into some of these questions in detail.
4 -Throwing an exception or halting with an errorĥ - Printing to console or reading from consoleĦ - Reading from a file or writing into a fileĪll these examples will raise a lot of questio ns even like how to write a useful program without any of these? Why reading from a file produces side effects, if we pass a file as an argument into the function ? How to write useful programs without loops ?.
