# Functions
NewCache creates a new thread-safe Cache.
NewExpression compiles an expression and returns the result in Expression struct Parameter expressionStr must follow syntax defined by https://github.com/Knetic/govaluate.
NewParams creates a new set of named Parameters.
# Structs
Cache is a thread-safe cache of compiled expressions.
Expression struct contains expression string as well as its compiled version.
# Type aliases
Parameters is a set of named parameters for the expression.