Mezzo

Mezzo is a dialect of ML with effects control and a fine-grained type system.

Main modules

Mezzo	This is the entry point of the program.
Driver	This module sets up a lexer and a parser to create an AST.

Type-checker modules

Definitions of types and binders

TypeCore	This module defines the syntax of types, as manipulated by the type-checker.
DeBruijn	Dealing with binders.
Types	This module provides a variety of functions for dealing with types, mostly built on top of `DeBruijn` and `TypeCore`.
ExpressionsCore	This module defines the syntax of expressions.
Expressions	This module defines substitution functions and binding functions on expressions as well as data type groups.

High-level type-checking modules

Merge	This module implements the merge operation.
Permissions	This module provides permission manipulation functions.
TypeChecker	This is the top of the pyramid: the module that actually performs type-checking.

Handling type errors

Derivations	This file provides a representation of typing derivations, built by `Permissions`.
TypeErrors	Everything you ever dreamed of for reporting errors.
DerivationPrinter	This module provide a convenient way to print a typing derivation into a (supposedly) human-readable form.

Various analyses performed by the type-checker

Fact analysis

DataTypeFlavor
Mode	The four modes.
Fact	Conjunction of hypotheses.
FactInference	This module analyzes data type declarations to synthesize facts about data types.

Other analyses

This module is entirely devoted to computing the variance of type parameters in data types.

Other type-checking operations

Dealing with modules and interfaces

Modules	Find the dependencies of a module.
Interfaces	Treatment of interfaces.
Exports	Handling the names exported by interfaces and implementations.

Manipulating types and expressions

From the external syntax down to the internal syntax

Parsing and lexing

SurfaceSyntax
Grammar
Lexer	The lexer for Mezzo.
ParserUtils
Resugar	This function converts an internal name to a possibly-qualified name in the surface syntax.

Front-end modules

KindCheck	This module implements a well-kindedness check for the types of the surface language.
TransSurface	Translating the surface syntax down into the core language syntax.

Misc

The data structures of Mezzo

Identifier	This functor creates a fresh abstract type of names.
Mark
Hashcons	A simple Hashconsing facility.
GMap
GSet	This is a stripped down version of `GSet` that describes both `Patricia` and `CompressedBitSet`.
Patricia	This is an implementation of Patricia trees, following Chris Okasaki's paper at the 1998 ML Workshop in Baltimore.
InfiniteArray	This module implements infinite arrays.
PersistentUnionFind	A persistent version of the classic union-find algorithm.
PersistentRef	This module implements a persistent store: in other words, it is a purely functional implementation of references, with an explicit store.

The Mezzo standard library

Bash	Provides wrappers for some bash fancy printing, mainly boxes and colors.
MzList	A bunch of useful functions for lists.
MzMap	Various missing functions from the `Map` module.
MzString	Various string utilities.
MzPprint
Option	No "J" prefix for this module since OCaml's standard library does not have an `Option` module.
Log	This module provides error reporting functions for Mezzo.

Misc

Debug
TestUtils
Utils

Dependency graph