Joseph Ferano
c64e91bdfa
Second stage of the milestone-2 frontend. calc-me.flan (12 decls) and sand.flan (20 decls) both parse end to end, and both are test deps so a regression fails `dune test` rather than surfacing at the CLI. Three silent-misparse bugs fixed along the way -- all cases that read cleanly and meant something else: - dotimes/defer/some/try/fn fell through to Call, discarding their binding and control-flow meaning. Now special forms. Forms from later milestones (handler-bind, restart-case, loop/recur, defmacro, signal, with-allocator, errdefer, await) are rejected outright rather than parsed as calls. - (Some 1) in first body position was read as a return type, because (Option f64) and (Some 1) are identical s-expressions and the heuristic was capitalisation. Now decided by the set of names actually declared as types, collected in a pre-pass -- exact, and order-independent so a type declared below its user still resolves. - Array literals in value position were rejected outright. Also adds NEXT.md with the handoff for the checker.
104 lines
4.3 KiB
OCaml
104 lines
4.3 KiB
OCaml
(** The AST: syntax with special forms recognised, before typing.
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Sugar is gone by this point. [when], [unless], [cond] and [and]/[or] are
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desugared into [If] and [Do]; they are compiler special forms until macros
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arrive at milestone 5, so there is nothing to preserve for a macroexpander
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to see yet.
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Types here are *surface* type expressions, not resolved types. [Ptr] and
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[Option] are still just names; the checker resolves them. *)
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(* ── Type expressions ──────────────────────────────────────────────── *)
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type texpr = { t : texpr_kind; tloc : Loc.t }
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and texpr_kind =
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| Tname of string (* i32 bool Cursor string *)
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| Tslice of texpr (* [u8] ptr+len *)
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| Tarray of len * texpr (* [4 f32] [rows [cols u32]] *)
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| Tmap of texpr * texpr (* {string i32} *)
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| Tapp of string * texpr list (* (Ptr Cursor) (Option f64) *)
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| Tfn of texpr list * texpr (* (Fn [a a] bool) *)
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(* An array length is an integer or a compile-time constant's name. *)
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and len =
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| Lint of int64
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| Lname of string
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(* ── Expressions ───────────────────────────────────────────────────── *)
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type expr = { e : expr_kind; loc : Loc.t }
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and expr_kind =
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| Int of int64
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| Float of float
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| Byte of int
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| Str of string
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| Kw of string (* :space — coerced at typed call sites *)
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| Quote of string (* 'skip-form — restart names *)
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| Var of string
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| Do of expr list
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| Let of binding list * expr list
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| If of expr * expr * expr option
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| While of expr * expr list
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| Return of expr option
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| Set of place * expr
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| Field of expr * string (* (.pos c) — auto-derefs one level *)
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| Call of expr * expr list
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| Match of expr * arm list
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| Struct of string * (string * expr) list (* (Cursor {:src s}) *)
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| Arr of expr list (* [0xE6B800FF ...] — a fixed array value *)
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(* These bind names or alter control flow, so none of them can be a call. *)
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| Fn of string list * expr list (* (fn [x y] ...) — non-escaping *)
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| Dotimes of string * expr * expr list (* (dotimes [i n] ...) *)
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| Defer of expr list (* runs on scope exit *)
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| Unwrap of unwrap * expr (* (some x) / (try x) *)
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(* Two unwrap operators, because they are two different things — plan.org. *)
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and unwrap = Usome | Utry
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and binding = { bname : string; bty : texpr option; bval : expr; bloc : Loc.t }
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(* The fixed list of assignable forms — spec-memory.md. Not setf. *)
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and place =
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| Pvar of string
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| Pfield of expr * string (* (set (.hp e) v) *)
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| Pindex of expr * expr list (* (set (at grid r c) v) *)
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| Pkey of expr * expr (* (set (get m k) v) *)
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| Pderef of expr (* (set (deref p) v) *)
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and arm = { pat : pattern; body : expr list; aloc : Loc.t }
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and pattern =
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| Pctor of string * string list (* (Some e) (Rect w h) None *)
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| Pwild (* _ :else *)
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(* ── Declarations ──────────────────────────────────────────────────── *)
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type field = { fname : string; fty : texpr; floc : Loc.t }
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type fn = {
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name : string;
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params : field list;
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ret : texpr option; (* None means Unit *)
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fbody : expr list;
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nloc : Loc.t;
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}
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type decl = { d : decl_kind; dloc : Loc.t }
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and decl_kind =
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| Package of string
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| Import of string * string (* alias, path *)
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| Defalias of string * texpr
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| Defstruct of string * field list
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| Defunion of string * variant list
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| Defn of fn
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(* value is optional: ZII. `uninit` opts out and is recorded as Uninit. *)
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| Defvar of string * texpr option * init
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| Defconst of string * texpr option * expr
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and variant = { vname : string; vfields : field list; vloc : Loc.t }
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and init = Zeroed | Uninit | Init of expr
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