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TODO 16.07.2009: update! and what is this pprinter_._ml?

Note :
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Aiborne.Mathieu jeudi 18 juin 2009, 12:56:55 (UTC+0100)

This continues the refactoring of Mikolaj of qml-framework

Journal :
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qml_base was a big bad blob
the typer is very jalous and not friendly at all about leting an other typer to be here. (bad if we want a HM(X) typer on day...) 

So, let's refactore a bit !

qml_base.ml and ast.ml are now splitted in to several modules

This modules are not intented to be open, but to be used like the ocaml library : 

List.fold_left .... much better than open List !!

So, use it in the same way :

QmlAstCons.ident ... 

Since opa has very common modules, the modules are named prefixed with Qml...


qmlAst is the defintion of the qml ast
Everymodule depends on it.

The work of having it separatly has allready be done by miko : thanks :)


It could possibly contain also common interfaces for the future implementations
(like typer, dbGen, etc...) 

it has no mli file because it define mostly only type (avoid duplication)

After that, there is all the qmlAst* family
They implements specific tools and must be short, simple, and with a strong mli

+++ jeudi 18 juin 2009, 14:18:46 (UTC+0100)

in the all the modules trx, there are direct call to FreshInt, depending directly on the representation of the ast. default.trx use ExprIdent as well.

a better approach is to use qmlAstCons systematicly in the all the parser trx

some files seams to be unused, it is comlicated to understand e.g. what comment is used ? comment.trx seams not to be

qml_parser and qmlMainParser have a lot of conflicted productions ....

but qml_parser seems not to be used : will be removed


+++ jeudi 18 juin 2009, 22:15:33 (UTC+0100)

Trx_qml_gen is contains Constructor and things with grammar

one part will be reported in qmlAstCons
the other part is a TODO !

it is also very weird that it provides some "to_string" features, but depends on qmlPrinters !


+++ vendredi 19 juin 2009, 00:14:02 (UTC+0100)

QmlPrinters : contain a (try-to-be-)parsable printer for qml, and an other one, more debug-friendly adding some annotation in the printed string (not parsable) like annotation or instance of types, ...

About monomorph !

It would be good that it is shared between all the differents typer (or not ?)

But it needs something like a TypeEnv.t
maybe then it is specific for any typer ?

But, there is an other thing about TypeEnv :

all the people who need a typer needs to know public interface about how to use it (so, at least, an API is public an the same for all differents typer (use a simple functor), and need some high level function, like : check-file ~output:"myfile.qmli" (or something like it)

There are severals possiblities, but which one is good ?

TypeEnv can be the same, shared in interface between typer, and with a public interface.

Then, it means that TypeScheme are the same everywhere (that is not so good, because I don't agree with the type of TypeScheme in the actual typer..., and would like to implement an other version of the typer with an other type for typescheme)

Possibly, we define an interface for a TypeEnv what is it, and what it is supposed to do --

then, monomorph is a functor of a TypeEnv

so, TypeEnv should contains some function like
TypeScheme.to_ty , and can abstract the type TypeScheme

In that way, we will be able to use the same monomorph if we write an HM(X) version of the typer

Don't call me a functor-man if you don't propose a simplier solution (but keeping the flexibility)

in fact, there is an other problem with it, and a functor is then not so good, you'll see it in the next part :

---

So, know, we arrived at the typer ...

What should be do in order that we could have as much typer as me want, sharing all what can be, and having specificities they want....


1) A interface with public types

  without that, it is impossible to change all the code that use several typer (call-code, like qml2ocaml, qmlToplevel, etc...)


2) We want to keep the high level functions (like output_keep_code) for each typer (so, we need a functor from the implementation to a high level ModuleTyper


That corresponds to the module MakeAstTyper that was in ast.ml before airborne.


3) Since the typevar are strongly incrusted in the AST, the typers must at least start from it (possibly redefine an private ast with other TypeVar in intern)

That could be a problem because for example, I disagree with the key managment in the old TypeVar version, so, I've modified it, and it could possibly change the behavior of other typer... Beware

Having a parametric type for the types would be difficult, and complexify the fact that we could change the typer dynamicly

4) what do we want about mixity use ?

    should it be possible to type a NewVal with a typer, and an other one with an other Typer ??

      if yes, then TypeEnv must be common. (that simplify the life of monomorph, but then we have the problem of fixed-implemented-TypeScheme 


 the typer needs some hack in the TypeEnv, hard to let it public ...


So maybe, implement a typer is something like :
implement an instance of TypeEnv, and the typer what does go together
(* *)						   


about TypeScheme :
------------------

I am quite scary because the side effect on TypeVar could have an effect an TypeScheme (for example, if we call unify on a ty from a TypeScheme, it compromise its integrity)

so, maybe the way to do it properly would be such a thing like : 

module TypeScheme :
sig 
  type t
  val public : t -> TypeVar.t list * ty

....
end
 


about annotation : maybe we could get in mind that it could be functionnal ?


QmlPrinters
Qml_base
Typer
Typer_new_subtyping_rules
QmlMainParser
Ast
MetaAst
Lambda_lifting
Monomorph
Trx_qml_gen
DbGenByPass
DbGenHelpers
DbGen_private
Schema_private
QmlDbGen



TODO : no time for it (too much things at one time)
BUT MUST BE DONE !!
---------------------------------------------------

unify the module qmlAstCons and the same part of it in trx_qml_gen

dont let appear any AST Constructor in the parser trx, use only constructor from qmlAstCons

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