https://github.com/bollu/unification
polymorphic type inference with unification from the Dragon book
https://github.com/bollu/unification
Last synced: 3 months ago
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polymorphic type inference with unification from the Dragon book
- Host: GitHub
- URL: https://github.com/bollu/unification
- Owner: bollu
- Created: 2020-12-20T16:03:20.000Z (almost 5 years ago)
- Default Branch: master
- Last Pushed: 2020-12-20T17:35:03.000Z (almost 5 years ago)
- Last Synced: 2025-06-25T07:03:05.616Z (3 months ago)
- Language: C++
- Size: 13.7 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Unification
An implementation of unification for type-checking polymorphic functions.
Implemented with reference to Chapter 6 of the dragon book, edition 1.
##### Internal state of the unification algorithm
```
==inferring |deref(deref(ptr()))|==
-{0} deref
-{1} deref[» [π [Pointer [αti]]] [αti]]
-{0} deref
-{1} deref[» [π [Pointer [αzi]]] [αzi]]
-{0} ptr
-{1} ptr[» [π] [Pointer [Pointer [Int]]]]
-{0} ptr[» [π] [Pointer [Pointer [Int]]]]():[αko]
-{u} [» [π] [αko]]~[» [π] [Pointer [Pointer [Int]]]]
-{u} [π]~[π]
-{v} [π]~[π] | cons
-{u} [αko]~[Pointer [Pointer [Int]]]
-{v} [Pointer [Pointer [Int]]]~[Pointer [Pointer [Int]]] | lvar
-{v} [» [π] [Pointer [Pointer [Int]]]]~[» [π] [Pointer [Pointer [Int]]]] | cons
-{1} ptr[» [π] [Pointer [Pointer [Int]]]]():[Pointer [Pointer [Int]]]
-{0} deref[» [π [Pointer [αzi]]] [αzi]](ptr[» [π] [Pointer [Pointer [Int]]]]():[Pointer [Pointer [Int]]]):[αno]
-{u} [» [π [Pointer [Pointer [Int]]]] [αno]]~[» [π [Pointer [αzi]]] [αzi]]
-{u} [π [Pointer [Pointer [Int]]]]~[π [Pointer [αzi]]]
-{u} [Pointer [Pointer [Int]]]~[Pointer [αzi]]
-{u} [Pointer [Int]]~[αzi]
-{v} [Pointer [Int]]~[Pointer [Int]] | rvar
-{v} [Pointer [Pointer [Int]]]~[Pointer [Pointer [Int]]] | cons
-{v} [π [Pointer [Pointer [Int]]]]~[π [Pointer [Pointer [Int]]]] | cons
-{u} [αno]~[Pointer [Int]]
-{v} [Pointer [Int]]~[Pointer [Int]] | lvar
-{v} [» [π [Pointer [Pointer [Int]]]] [Pointer [Int]]]~[» [π [Pointer [Pointer [Int]]]] [Pointer [Int]]] | cons
-{1} deref[» [π [Pointer [Pointer [Int]]]] [Pointer [Int]]](ptr[» [π] [Pointer [Pointer [Int]]]]():[Pointer [Pointer [Int]]]):[Pointer [Int]]
-{0} deref[» [π [Pointer [αti]]] [αti]](deref[» [π [Pointer [Pointer [Int]]]] [Pointer [Int]]](ptr[» [π] [Pointer [Pointer [Int]]]]():[Pointer [Pointer [Int]]]):[Pointer [Int]]):[αro]
-{u} [» [π [Pointer [Int]]] [αro]]~[» [π [Pointer [αti]]] [αti]]
-{u} [π [Pointer [Int]]]~[π [Pointer [αti]]]
-{u} [Pointer [Int]]~[Pointer [αti]]
-{u} [Int]~[αti]
-{v} [Int]~[Int] | rvar
-{v} [Pointer [Int]]~[Pointer [Int]] | cons
-{v} [π [Pointer [Int]]]~[π [Pointer [Int]]] | cons
-{u} [αro]~[Int]
-{v} [Int]~[Int] | lvar
-{v} [» [π [Pointer [Int]]] [Int]]~[» [π [Pointer [Int]]] [Int]] | cons
-{1} deref[» [π [Pointer [Int]]] [Int]](deref[» [π [Pointer [Pointer [Int]]]] [Pointer [Int]]](ptr[» [π] [Pointer [Pointer [Int]]]]():[Pointer [Pointer [Int]]]):[Pointer [Int]]):[Int]
```