mirror of
https://github.com/CatalaLang/catala.git
synced 2024-09-19 16:28:12 +03:00
44 lines
1.8 KiB
Plaintext
44 lines
1.8 KiB
Plaintext
{0 Default calculus}
|
|
|
|
This module contains a generic AST structure, various type definitions and
|
|
helpers that are reused in various passes of the compiler.
|
|
|
|
{1 The [Shared_ast.Definitions] module}
|
|
|
|
The main module {!module: Shared_ast} is exposed at top-level of
|
|
the library (so that [open Shared_ast] gives access to the structures). It
|
|
defines literals, operators, and in particular the type {!type:Shared_ast.naked_gexpr}.
|
|
|
|
The {!type:Shared_ast.naked_gexpr} type regroups all the cases for the {{:
|
|
../dcalc.html} Dcalc} and {{: ../lcalc.html} Lcalc} ASTs, with unconstrained
|
|
annotations (used for positions, types, etc.). A GADT is used to eliminate
|
|
irrelevant cases, so that e.g. [(dcalc, _) naked_gexpr] doesn't have the [ERaise] and
|
|
[ECatch] cases, while [(lcalc, _) naked_gexpr] doesn't have [EDefault].
|
|
|
|
For example, Lcalc expressions are then defined as
|
|
[type 'm naked_expr = (Shared_ast.lcalc, 'm) Shared_ast.naked_gexpr].
|
|
|
|
This makes it possible to write a single function that works on the different
|
|
ASTs, by having it take a [('a, _) naked_gexpr] as input, while retaining a much
|
|
stricter policy than polymorphic variants.
|
|
|
|
The module additionally defines the encompassing [scope] and [program]
|
|
structures that are also shared between different compiler passes.
|
|
|
|
{1 Helper library}
|
|
|
|
The {!module: Shared_ast.Var} defines ['e Var.Set.t] and [('e, _) Var.Map.t]
|
|
types that are useful to handle variables for the different ['e] expression
|
|
types without re-instanciating [Set.Make] and [Map.Make] each time.
|
|
|
|
{!module: Shared_ast.Expr} contains various helpers to build well-formed
|
|
expressions, and for traversal.
|
|
|
|
The following modules are dedicated to handling the program structure around
|
|
expressions. Note that these don't make sense for the early compiler passes (up
|
|
to [Scopelang]).
|
|
|
|
|
|
{!modules: Shared_ast.Scope Shared_ast.Program}
|
|
|