docs/programming/hoon/mint.md · urbit.org

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1---

2sort: 6

3next: true

4Title: Compiler

5---

7# Compiler: `mint`

9`mint` is the Hoon compiler. It maps a cell `{subject/span

10source/twig}` to a cell `{product/span formula/nock}`, where

11`span` is a type, `twig` is a compiled expression, and `nock` is

12a Nock formula.

14Calculating the output type from the input type and the source

15code is called "type inference." If you've used another typed

16functional language, like Haskell, Hoon's type inference does the

17same job but with less intelligence.

19Haskell infers backward and forward; Hoon only infers forward.

20Hoon can't figure out the type of a noun from how you use it,

21only from how you make it. Hoon can infer tail recursion, but

22not head recursion.

24Low-powered type inference means you need more type annotations,

25which makes your program more readable anyway. (Also, the dumber

26the compiler, the easier it is for a dumb human to understand

27what the compiler is thinking.)