reads package:mixed-types-num

equivalent to readsPrec with a precedence of 0.

A parser for a type a, represented as a function that takes a String and returns a list of possible parses as (a,String) pairs. Note that this kind of backtracking parser is very inefficient; reading a large structure may be quite slow (cf ReadP).

attempts to parse a value from the front of the string, returning a list of (parsed value, remaining string) pairs. If there is no successful parse, the returned list is empty. Derived instances of Read and Show satisfy the following:

• (x,"") is an element of (readsPrec d (showsPrec d x "")).

That is, readsPrec parses the string produced by showsPrec, and delivers the value that showsPrec started with.