flan/lib/load.ml
Joseph Ferano d2bc2bd714 The wrapper per binding was always mechanical, so write it here
84 hand-written C wrappers is the shape of a job the compiler should be
doing. The reason the shim exists is unchanged and is not negotiable: a
small aggregate's calling convention is a per-target classification, not
part of its layout, and reproducing x86-64, arm64 and wasm32 inside
emit.ml is three classifiers to keep correct forever, where a mistake
reads as a field full of garbage rather than as a link error. clang does
it, per target, for free. So the C stays; the typing of it stops.

declare-c names the library's own function in the library's own
signature, and Shim emits the typedefs, the extern prototype, the
flattening wrapper and the flattened declaration the Flan side calls.

It is a second form rather than a change to declare because no
structural rule can separate them: (declare start-raw [path string] i32
"flan_agent_start") means the symbol takes ptr+len, and (declare-c
init-window [w i32 h i32 title string] "InitWindow") means it takes a
NUL-terminated char *. Same shape, opposite claims. declare is
untouched, so sqrtf and vendor/agent keep working unedited.

The generated C rides on Tast.program rather than beside it, so the CLI,
the REPL and the acceptance table all carry it without being told about
it. `flan shim` prints it, because a wrong binding is wrong in a wrapper
that is otherwise on no disk anywhere.
2026-09-11 20:26:00 +07:00

314 lines
13 KiB
OCaml

(** Imports: {v (import rl "vendor:raylib") v} resolved into ordinary
declarations, before the checker ever runs.
The directory is the package (plan.org, Modules), so a path is a directory
and every [.flan] file in it contributes. [vendor:] and [core:] are
collections — root-directory aliases, as in Odin — and are resolved by
walking up from the importing file until a directory of that name is found.
No project file, no manifest: a loose file in a scratch directory is still
a package of one.
Importing is a rename, done here: every top-level name the package declares
becomes [alias/name], and every use of one of its own names — in a type, in
a body, in a struct literal — is rewritten to match. Local bindings shadow,
so a parameter named like a package function stays the parameter. Nothing
downstream knows a package existed; the checker sees one flat list of
declarations with names that happen to contain a slash.
That is not a module system yet. There is no visibility, no cycle
detection, and a package cannot import another one — milestone 4 needs one
package, imported once, and the rest can wait for a use that exercises it.
A package may also carry the C it binds to. Every [.c] file in the
directory is compiled into the build, and a file named [link] lists extra
linker arguments, one per line. That is where the aggregate calling
convention lives: a shim written in C means clang classifies [Vector2] and
[Color] correctly on x86-64, arm64 and wasm32 alike, and [emit.ml] never
learns the difference. *)
type t = {
decls : Ast.decl list;
csrcs : string list; (* C sources compiled into the build *)
lflags : string list; (* extra linker arguments *)
(* Which alias each package's directory was imported under, and the names it
owns. A file on disk does not say what it is called from outside — the
*importer* chooses that — so this is the only place the answer exists, and
a REPL editing a package's source needs it to know that [settle] typed in
sand-sim/sim.flan means [sim/settle] to the running program. *)
pkgs : pkg list;
}
and pkg = { alias : string; dir : string; owns : string list }
let fail loc fmt = Printf.ksprintf (fun m -> raise (Loc.Error (loc, m))) fmt
(* "vendor:raylib" -> the collection "vendor" and the subpath "raylib". A path
with no colon is relative to the importing file's own directory. *)
let split_path path =
match String.index_opt path ':' with
| None -> None, path
| Some i ->
Some (String.sub path 0 i),
String.sub path (i + 1) (String.length path - i - 1)
(* Walk up from [dir] looking for a subdirectory named [name]. Stops at the
filesystem root, so a missing collection is an error and never a silent
search of the whole machine. *)
let rec find_collection dir name =
let candidate = Filename.concat dir name in
if Sys.file_exists candidate && Sys.is_directory candidate then Some candidate
else
let parent = Filename.dirname dir in
if String.equal parent dir then None else find_collection parent name
let resolve_dir ~file loc path =
let here =
let d = Filename.dirname file in
if Filename.is_relative d then Filename.concat (Sys.getcwd ()) d else d
in
match split_path path with
| None, rel ->
let d = Filename.concat here rel in
if Sys.file_exists d && Sys.is_directory d then d
else fail loc "no package directory at %s" d
| Some collection, rel ->
(match find_collection here collection with
| None ->
fail loc
"the collection %s: is a directory named %s somewhere above %s, and \
there is none" collection collection here
| Some root ->
let d = Filename.concat root rel in
if Sys.file_exists d && Sys.is_directory d then d
else fail loc "the package %s is not at %s" path d)
let entries dir suffix =
Sys.readdir dir
|> Array.to_list
|> List.filter (fun f -> Filename.check_suffix f suffix)
|> List.sort String.compare
|> List.map (Filename.concat dir)
(* ── Qualifying an imported package ────────────────────────────────── *)
let qualify alias n = alias ^ "/" ^ n
(* The type names the package itself declares. Only these are rewritten: a
reference to [i32] or to [Ptr] must survive untouched. *)
let rec rename_texpr owned alias (t : Ast.texpr) : Ast.texpr =
let k =
match t.Ast.t with
| Ast.Tname n when List.mem n owned -> Ast.Tname (qualify alias n)
| Ast.Tname _ as k -> k
| Ast.Tslice e -> Ast.Tslice (rename_texpr owned alias e)
(* The length too: [rows] in [[rows [cols u32]]] is an ordinary
compile-time constant of the package, not part of the type syntax. *)
| Ast.Tarray (l, e) ->
let l =
match l with
| Ast.Lname n when List.mem n owned -> Ast.Lname (qualify alias n)
| l -> l
in
Ast.Tarray (l, rename_texpr owned alias e)
| Ast.Tmap (k, v) ->
Ast.Tmap (rename_texpr owned alias k, rename_texpr owned alias v)
| Ast.Tapp (n, args) ->
Ast.Tapp (n, List.map (rename_texpr owned alias) args)
| Ast.Tfn (ps, r) ->
Ast.Tfn (List.map (rename_texpr owned alias) ps, rename_texpr owned alias r)
in
{ t with Ast.t = k }
(* Bodies too, once a package may define and not only declare. A package-local
name is qualified wherever it is *used*; a local binding shadows it, which is
why [bound] is carried down through [let], [fn] and [dotimes]. Everything
else — field names, keywords, enum members — is not a top-level name and is
left alone. *)
let rec rename_expr owned alias bound (e : Ast.expr) : Ast.expr =
let go = rename_expr owned alias bound in
let gos = List.map go in
let name n = if List.mem n owned && not (List.mem n bound) then qualify alias n else n in
let k =
match e.Ast.e with
| Ast.Int _ | Ast.Float _ | Ast.Byte _ | Ast.Str _ | Ast.Kw _
| Ast.Quote _ -> e.Ast.e
| Ast.Var n -> Ast.Var (name n)
| Ast.Do body -> Ast.Do (gos body)
| Ast.Let (bs, body) ->
(* Sequential, as [let] itself is: each initialiser sees the bindings
before it and not its own. *)
let bound, bs =
List.fold_left
(fun (bound, acc) (b : Ast.binding) ->
let b =
{ b with
Ast.bty = Option.map (rename_texpr owned alias) b.Ast.bty;
bval = rename_expr owned alias bound b.Ast.bval }
in
(b.Ast.bname :: bound, b :: acc))
(bound, []) bs
in
Ast.Let (List.rev bs, List.map (rename_expr owned alias bound) body)
| Ast.If (c, t, e') -> Ast.If (go c, go t, Option.map go e')
| Ast.While (c, body) -> Ast.While (go c, gos body)
| Ast.Return v -> Ast.Return (Option.map go v)
| Ast.Set (p, v) -> Ast.Set (rename_place owned alias bound p, go v)
| Ast.Field (t, f) -> Ast.Field (go t, f)
| Ast.Call (h, args) -> Ast.Call (go h, gos args)
| Ast.Match (sc, arms) ->
Ast.Match (go sc,
List.map (fun (a : Ast.arm) ->
let bound =
match a.Ast.pat with
| Ast.Pctor (_, ns) -> ns @ bound
| Ast.Pwild -> bound
in
{ a with Ast.body = List.map (rename_expr owned alias bound)
a.Ast.body }) arms)
| Ast.Struct (n, kvs) ->
Ast.Struct (name n, List.map (fun (k, v) -> (k, go v)) kvs)
| Ast.Arr items -> Ast.Arr (gos items)
| Ast.Fn (ps, body) ->
Ast.Fn (ps, List.map (rename_expr owned alias (ps @ bound)) body)
| Ast.Dotimes (i, n, body) ->
Ast.Dotimes (i, go n, List.map (rename_expr owned alias (i :: bound)) body)
| Ast.Defer body -> Ast.Defer (gos body)
| Ast.Unwrap (u, v) -> Ast.Unwrap (u, go v)
| Ast.Signal (k, c) -> Ast.Signal (k, go c)
(* A restart name is not a top-level name — it is looked up on the restart
stack, not in the environment — so an import does not qualify it. Only
the bodies are rewritten. *)
| Ast.RestartCase (body, clauses) ->
Ast.RestartCase
(go body,
List.map
(fun (c : Ast.rclause) -> { c with Ast.rbody = gos c.Ast.rbody })
clauses)
| Ast.InvokeRestart _ -> e.Ast.e
(* A clause names a condition *type*, which an import renames like any
other, and binds a name for the condition inside its own body. *)
| Ast.HandlerBind (clauses, body) ->
Ast.HandlerBind
(List.map
(fun (c : Ast.hclause) ->
{ c with
Ast.hty = rename_texpr owned alias c.Ast.hty;
hbody =
List.map (rename_expr owned alias (c.Ast.hname :: bound))
c.Ast.hbody })
clauses,
gos body)
in
{ e with Ast.e = k }
and rename_place owned alias bound (p : Ast.place) : Ast.place =
let go = rename_expr owned alias bound in
match p with
| Ast.Pvar n ->
Ast.Pvar (if List.mem n owned && not (List.mem n bound) then qualify alias n else n)
| Ast.Pfield (t, f) -> Ast.Pfield (go t, f)
| Ast.Pindex (t, idx) -> Ast.Pindex (go t, List.map go idx)
| Ast.Pderef t -> Ast.Pderef (go t)
let rename_field owned alias (f : Ast.field) : Ast.field =
{ f with Ast.fty = rename_texpr owned alias f.Ast.fty }
let qualify_decl owned alias (d : Ast.decl) : Ast.decl =
let loc = d.Ast.dloc in
let k =
match d.Ast.d with
| Ast.Declare (fn, csym) ->
Ast.Declare
({ fn with
Ast.name = qualify alias fn.Ast.name;
params = List.map (rename_field owned alias) fn.Ast.params;
ret = Option.map (rename_texpr owned alias) fn.Ast.ret },
csym)
(* The same as [Declare]: [Shim] has not run yet, so this is still the
library's own signature and the names in it are the package's. *)
| Ast.DeclareC (fn, csym) ->
Ast.DeclareC
({ fn with
Ast.name = qualify alias fn.Ast.name;
params = List.map (rename_field owned alias) fn.Ast.params;
ret = Option.map (rename_texpr owned alias) fn.Ast.ret },
csym)
| Ast.Defenum (n, ms) -> Ast.Defenum (qualify alias n, ms)
| Ast.Defalias (n, t) ->
Ast.Defalias (qualify alias n, rename_texpr owned alias t)
| Ast.Defconst (n, t, v) ->
Ast.Defconst (qualify alias n,
Option.map (rename_texpr owned alias) t,
rename_expr owned alias [] v)
| Ast.Defstruct (n, fs) ->
Ast.Defstruct (qualify alias n, List.map (rename_field owned alias) fs)
| Ast.Defvar (n, t, init) ->
Ast.Defvar (qualify alias n, Option.map (rename_texpr owned alias) t,
(match init with
| Ast.Init v -> Ast.Init (rename_expr owned alias [] v)
| other -> other))
| Ast.Defn fn ->
let params = List.map (rename_field owned alias) fn.Ast.params in
let bound = List.map (fun (p : Ast.field) -> p.Ast.fname) fn.Ast.params in
Ast.Defn
{ fn with
Ast.name = qualify alias fn.Ast.name;
params;
ret = Option.map (rename_texpr owned alias) fn.Ast.ret;
fbody = List.map (rename_expr owned alias bound) fn.Ast.fbody }
| Ast.Package _ -> Ast.Package alias
| Ast.Import _ ->
fail loc "an imported package may not import another one yet (milestone 4)"
| Ast.Defunion (n, _) ->
fail loc "%s is a union, and an imported union is not implemented yet \
(milestone 4)" n
in
{ d with Ast.d = k }
(* Every top-level name the package declares — types and values alike, since a
use site is rewritten by name and the two never collide in one namespace. *)
let owned_names (ds : Ast.decl list) =
List.filter_map Ast.declared_name ds
let import ~loc alias dir =
let files = entries dir ".flan" in
if files = [] then fail loc "the package at %s has no .flan file" dir;
let ds = List.concat_map (fun f -> Parse.program (Reader.read_file f)) files in
let owned = owned_names ds in
let decls = List.map (qualify_decl owned alias) ds in
let lflags =
let path = Filename.concat dir "link" in
if not (Sys.file_exists path) then []
else begin
let ch = open_in path in
let rec go acc =
match input_line ch with
| line ->
let line = String.trim line in
go (if line = "" || line.[0] = '#' then acc else line :: acc)
| exception End_of_file -> List.rev acc
in
let r = go [] in
close_in ch; r
end
in
{ decls; csrcs = entries dir ".c"; lflags;
pkgs = [ { alias; dir; owns = owned } ] }
(* ── The one entry point ───────────────────────────────────────────── *)
let program ~file (decls : Ast.decl list) : t =
List.fold_left
(fun acc (d : Ast.decl) ->
match d.Ast.d with
| Ast.Import (alias, path) ->
let dir = resolve_dir ~file d.Ast.dloc path in
let p = import ~loc:d.Ast.dloc alias dir in
{ decls = acc.decls @ p.decls;
csrcs = acc.csrcs @ p.csrcs;
lflags = acc.lflags @ p.lflags;
pkgs = acc.pkgs @ p.pkgs }
| _ -> { acc with decls = acc.decls @ [ d ] })
{ decls = []; csrcs = []; lflags = []; pkgs = [] }
decls