Trees and languages

0. How to run dotnet interpreter ?
1. (let, functions, types'synonyms and unions)
   How to define pi in F# ? How to compute the area of a circle in F# ?
   What is the area of a circle having radius equals to 2 ?
   Define pi, the area function and the real numbers' type.
   Also explain how to deal with expression such as area (-1.0).
2. How to define boolean set in F# ?
3. (match) How to define standard booleans' operator (not, and, etc.) ?
4. (trees, abstract syntax) How to define set of boolean expressions ?
5. How to print or evaluate boolean expressions ?
6. (parametric types) How to generalize boolean expressions into any kind of expressions with, for instance, float expressions used in fuzzy logic ?
7. (lists) How to model streams that can be either empty or composed with a value nd another stream ?
8. (map) How to apply a function f to all the value of a stream ?
9. (filter) How to select the element of a stream having a property p ?
10. (map2) How to compose two streams having the same size with a function/operator g ?
11. (reduce/fold) How to "merge" of tha values of a stream with a function/operator o ?

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