Three things in this commit:
1. Integer / is now truncate-toward-zero on ints, IEEE on floats. The
eval-op handler for '/' checks (number? + (= (round x) x)) on both
sides; if both integral, applies host floor/ceil based on sign;
otherwise falls through to host '/'.
2. Fixes Int.rem, which was returning 0 because (a - b * (a / b))
was using float division: 17 - 5 * 3.4 = 0.0. Now Int.rem 17 5 = 2.
3. Int module fleshed out:
max_int / min_int / zero / one / minus_one,
succ / pred / neg, add / sub / mul / div / rem,
equal, compare.
Also adds globals: max_int, min_int, abs_float, float_of_int,
int_of_float (the latter two are identity in our dynamic runtime).
17 / 5 = 3
-17 / 5 = -3 (trunc toward zero)
Int.rem 17 5 = 2
Int.compare 5 3 = 1
Eight new Array functions, all in OCaml syntax inside runtime.sx,
delegating to the corresponding List operation on the cell's
underlying list:
sort cmp a -> a := List.sort cmp !a (* mutates the cell *)
stable_sort = sort
fast_sort = sort
append a b -> ref (List.append !a !b)
sub a pos n -> ref (take n (drop pos !a))
exists p -> List.exists p !a
for_all p -> List.for_all p !a
mem x a -> List.mem x !a
Round-trip:
let a = Array.of_list [3;1;4;1;5;9;2;6] in
Array.sort compare a;
Array.to_list a = [1;1;2;3;4;5;6;9]
parse-atom-postfix's '.()' branch now disambiguates between let-open
and array-get based on whether the head is a module path (':con' or
':field' chain rooted in ':con'). Module paths still emit
(:let-open M EXPR); everything else emits (:array-get ARR I).
Eval handles :array-get by reading the cell's underlying list at
index. The '<-' assignment handler now also accepts :array-get lhs
and rewrites the cell with one position changed.
Idiomatic OCaml array code now works:
let a = Array.make 5 0 in
for i = 0 to 4 do a.(i) <- i * i done;
a.(3) + a.(4) = 25
let a = Array.init 4 (fun i -> i + 1) in
a.(0) + a.(1) + a.(2) + a.(3) = 10
List.(length [1;2;3]) = 3 (* unchanged: List is a module *)
Array module (runtime.sx, OCaml syntax):
Backed by a 'ref of list'. make/length/get/init build the cell;
set rewrites the underlying list with one cell changed (O(n) but
works for short arrays in baseline programs). Includes
iter/iteri/map/mapi/fold_left/to_list/of_list/copy/blit/fill.
(op) operator sections (parser.sx, parse-atom):
When the token after '(' is a binop (any op with non-zero
precedence in the binop table) and the next token is ')', emit
(:fun ('a' 'b') (:op OP a b)) — i.e. (+) becomes fun a b -> a + b.
Recognises every binop including 'mod', 'land', '^', '@', '::',
etc.
Lets us write:
List.fold_left (+) 0 [1;2;3;4;5] = 15
let f = ( * ) in f 6 7 = 42
List.map ((-) 10) [1;2;3] = [9;8;7]
let a = Array.make 5 7 in
Array.set a 2 99;
Array.fold_left (+) 0 a = 127
Tokenizer already classified backtick-uppercase as a ctor identical
to a nominal one, but it had never been exercised by the suite. This
commit adds three smoke tests confirming that nullary, n-ary, and
list-of-polyvariant patterns all match:
let x = polyvar(Foo) in match x with polyvar(Foo) -> 1 | polyvar(Bar) -> 2
let x = polyvar(Pair) (5, 7) in
match x with polyvar(Pair) (a, b) -> a + b | _ -> 0
List.map (fun x -> match x with polyvar(On) -> 1 | polyvar(Off) -> 0)
[polyvar(On); polyvar(Off); polyvar(On)]
(In the actual SX, polyvar(X) is the literal backtick-X — backticks
in this commit message are escaped to avoid shell interpretation.)
Since OCaml-on-SX is dynamic, there's no structural row inference,
but matching by tag works.
sort_uniq:
Sort with the user comparator, then walk the sorted list dropping
any element equal to its predecessor. Output is sorted and unique.
List.sort_uniq compare [3;1;2;1;3;2;4] = [1;2;3;4]
find_map:
Walk until the user fn returns Some v; return that. If all None,
return None.
List.find_map (fun x -> if x > 5 then Some (x * 2) else None)
[1;2;3;6;7]
= Some 12
Both defined in OCaml syntax in runtime.sx — no host primitive
needed since they're pure list traversals over existing operations.
Six new String functions, all in OCaml syntax inside runtime.sx:
iter : index-walk with side-effecting f
iteri : iter with index
fold_left : thread accumulator left-to-right
fold_right: thread accumulator right-to-left
to_seq : return a char list (lazy in real OCaml; eager here)
of_seq : concat a char list back to a string
Round-trip:
String.of_seq (List.rev (String.to_seq "hello")) = "olleh"
Note: real OCaml's Seq is lazy. We return a plain list because the
existing stdlib already provides exhaustive list operations and we
don't yet have lazy sequences. If a baseline needs Seq.unfold or
similar, we'll graduate to a proper Seq module then.
frequency.ml exercises the recently-added Hashtbl.iter / fold +
Hashtbl.find_opt + s.[i] indexing + for-loop together: build a
char-count table for 'abracadabra' then take the max via
Hashtbl.fold. Expected = 5 (a x 5). Total 25 baseline programs.
Format module added as a thin alias of Printf — sprintf, printf, and
asprintf all delegate to Printf.sprintf. The dynamic runtime doesn't
distinguish boxes/breaks, so format strings work the same as in
Printf and most Format-using OCaml programs now compile.
Tokenizer already had 'lazy' as a keyword. This commit wires it through:
parser : parse-prefix emits (:lazy EXPR), like the existing 'assert'
handler.
eval : creates a one-element cell with state ('Thunk' expr env).
host : _lazy_force flips the cell to ('Forced' v) on first call
and returns the cached value thereafter.
runtime : module Lazy = struct let force lz = _lazy_force lz end.
Memoisation confirmed by tracking a side-effect counter through two
forces of the same lazy:
let counter = ref 0 in
let lz = lazy (counter := !counter + 1; 42) in
let a = Lazy.force lz in
let b = Lazy.force lz in
(a + b) * 100 + !counter = 8401 (= 84*100 + 1)
New host primitive _hashtbl_to_list returns the entries as a list of
OCaml tuples — ('tuple' k v) form, matching the AST representation
that the pattern-match VM (:ptuple) expects. Without that exact
shape, '(k, v) :: rest' patterns fail to match.
Hashtbl.iter / Hashtbl.fold in runtime walk that list with the user
fn. This closes a long-standing gap: previously Hashtbl was opaque
once values were written (we could only find_opt one key at a time).
let t = Hashtbl.create 4 in
Hashtbl.add t "a" 1; Hashtbl.add t "b" 2; Hashtbl.add t "c" 3;
Hashtbl.fold (fun _ v acc -> acc + v) t 0 = 6
Replaces the stub sprintf in runtime.sx with a real implementation:
walk fmt char-by-char accumulating a prefix; on recognised %X return a
one-arg fn that formats the arg and recurses on the rest of fmt. The
function self-curries to the spec count — there's no separate arity
machinery, just a closure chain.
Specs: %d (int), %s (string), %f (float), %c (char/string in our model),
%b (bool), %% (literal). Unknown specs pass through.
Same expression returns a string (no specs) or a function (>=1 spec) —
OCaml proper would reject this; works fine in OCaml-on-SX's dynamic
runtime.
Also adds top-level aliases:
string_of_int = _string_of_int
string_of_float = _string_of_float
string_of_bool = if b then "true" else "false"
int_of_string = _int_of_string
Printf.sprintf "x=%d" 42 = "x=42"
Printf.sprintf "%s = %d" "answer" 42 = "answer = 42"
Printf.sprintf "%d%%" 50 = "50%"
Tokenizer already classified 'assert' as a keyword; this commit wires
it through:
parser : parse-prefix dispatches like 'not' — advance, recur, wrap
as (:assert EXPR).
eval : evaluate operand; nil on truthy, host-error 'Assert_failure'
on false. Caught cleanly by existing try/with.
assert true; 42 = 42
let x = 5 in assert (x = 5); x + 1 = 6
try (assert false; 0) with _ -> 99 = 99
parse-atom-postfix now dispatches three cases after consuming '.':
.field -> existing field/module access
.(EXPR) -> existing local-open
.[EXPR] -> new string-get syntax (this commit)
Eval reduces (:string-get S I) to host (nth S I), which already returns
a one-character string for OCaml's char model.
Lets us write idiomatic OCaml string traversal:
let s = "hi" in
let n = ref 0 in
for i = 0 to String.length s - 1 do
n := !n + Char.code s.[i]
done;
!n (* = 209 *)
Side-quest emerged from adding roman.ml baseline (Roman numeral greedy
encoding): top-level 'let () = expr' was unsupported because
ocaml-parse-program's parse-decl-let consumed an ident strictly. Now
parse-decl-let recognises a leading '()' as a unit binding and
synthesises a __unit_NN name (matching how parse-let already handles
inner-let unit patterns).
roman.ml exercises:
* tuple list literal [(int * string); ...]
* recursive pattern match on tuple-cons
* String.length + List.fold_left
* the new top-level let () support (sanity in a comment, even though
the program ends with a bare expression for the test harness)
Bumped lib/ocaml/test.sh server timeout 180->360s — the recent surge in
test count plus a CPU-contended host was crowding out the sole epoch
reaching the deeper smarts.
In parse-atom-postfix, after consuming '.', if the next token is '(',
parse the inner expression and emit (:let-open M EXPR) instead of
:field. Cleanly composes with the existing :let-open evaluator and
loops to allow chained dot postfixes.
List.(length [1;2;3]) = 3
List.(map (fun x -> x + 1) [1;2;3]) = [2;3;4]
Option.(map (fun x -> x * 10) (Some 4)) = Some 40
Parser detects 'let open' as a separate let-form, parses M as a path
(Ctor(.Ctor)*) directly via inline AST construction (no source slicing
since cur-pos is only available in ocaml-parse-program), and emits
(:let-open PATH BODY).
Eval resolves the path to a module dict and merges its bindings into
the env for body evaluation. Now:
let open List in map (fun x -> x * 2) [1;2;3] = [2;4;6]
let open Option in map (fun x -> x + 1) (Some 5) = Some 6
ocaml-eval-module now handles :def-mut and :def-rec-mut decls so
'module M = struct let rec a n = ... and b n = ... end' works. The
def-rec-mut version uses cell-based mutual recursion exactly as the
top-level version.
let NAME [PARAMS] : T = expr and (expr : T) parse and skip the type
source. Runtime no-op since SX is dynamic. Works in inline let,
top-level let, and parenthesised expressions:
let x : int = 5 ;; x + 1 -> 6
let f (x : int) : int = x + 1 in f 41 -> 42
(5 : int) -> 5
((1 + 2) : int) * 3 -> 9
Parser: in parse-decl-type, dispatch on the post-= token:
'|' or Ctor -> sum type
'{' -> record type
otherwise -> type alias (skip to boundary)
AST (:type-alias NAME PARAMS) with body discarded. Runtime no-op since
SX has no nominal types.
poly_stack.ml baseline exercises:
module type ELEMENT = sig type t val show : t -> string end
module IntElem = struct type t = int let show x = ... end
module Make (E : ELEMENT) = struct ... use E.show ... end
module IntStack = Make(IntElem)
Demonstrates the substrate handles signature decls + abstract types +
functor parameter with sig constraint.
parse-try now consumes optional 'when GUARD-EXPR' before -> and emits
(:case-when PAT GUARD BODY). Eval try clause loop dispatches on case /
case-when and falls through on guard false — same semantics as match.
Examples:
try raise (E 5) with | E n when n > 0 -> n | _ -> 0 = 5
try raise (E (-3)) with | E n when n > 0 -> n | _ -> 0 = 0
try raise (E 5) with | E n when n > 100 -> n | E n -> n + 1000 = 1005
parse-function now consumes optional 'when GUARD-EXPR' before -> and
emits (:case-when PAT GUARD BODY) — same handling as match clauses.
function-style sign extraction now works:
(function | n when n > 0 -> 1 | n when n < 0 -> -1 | _ -> 0)
ocaml-type-of-program now handles :def-mut (sequential generalize) and
:def-rec-mut (pre-bind tvs, infer rhs, unify, generalize all, infer
body — same algorithm as the inline let-rec-mut version).
Mutual top-level recursion now type-checks:
let rec even n = ... and odd n = ...;; even 10 : Bool
let rec map f xs = ... and length lst = ...;; map :
('a -> 'b) -> 'a list -> 'b list
<- added to op-table at level 1 (same as :=). Eval short-circuits on
<- to mutate the lhs's field via host SX dict-set!. The lhs must be a
:field expression; otherwise raises.
Tested:
let r = { x = 1; y = 2 } in r.x <- 5; r.x (5)
let r = { x = 0 } in for i = 1 to 5 do r.x <- r.x + i done; r.x (15)
let r = { name = ...; age = 30 } in r.name <- "Alice"; r.name
The 'mutable' keyword in record type decls is parsed-and-discarded;
runtime semantics: every field is mutable. Phase 2 closes this gap
without changing the dict-based record representation.
type r = { x : int; mutable y : string } parses to
(:type-def-record NAME PARAMS FIELDS) with FIELDS each (NAME) or
(:mutable NAME). Parser dispatches on { after = to parse field list.
Field-type sources are skipped (HM registration TBD). Runtime no-op
since records already work as dynamic dicts.
print_string / print_endline / print_int / print_newline now route to
SX display primitive (not the non-existent print/println). print_endline
appends '\n'.
let _ = expr ;; at top level confirmed working via the
wildcard-param parser.
ocaml-infer-let-mut: each rhs inferred in parent env, generalized
sequentially before adding to body env.
ocaml-infer-let-rec-mut: pre-bind all names with fresh tvs; infer
each rhs against the joint env, unify each with its tv, then
generalize all and infer body.
Mutual recursion now type-checks:
let rec even n = if n = 0 then true else odd (n - 1)
and odd n = if n = 0 then false else even (n - 1)
in even : Int -> Bool
Option: join, to_result, some, none.
Result: value, iter, fold.
Bytes: length, get, of_string, to_string, concat, sub — thin alias of
String (SX has no separate immutable byte type).
Ordering fix: Bytes module placed after String so its closures capture
String in scope. Earlier draft put Bytes before String which made
String.* lookups fail with 'not a record/module' (treated as nullary
ctor).
Parser fix: at-app-start? and parse-app's loop recognise prefix !
as a deref of the next app arg. So 'List.rev !b' parses as
'(:app List.rev (:deref b))' instead of stalling at !.
Buffer module backed by a ref holding string list:
create _ = ref []
add_string b s = b := s :: !b
contents b = String.concat "" (List.rev !b)
add_char/length/clear/reset
Both written in OCaml inside lib/ocaml/runtime.sx:
module Map = struct module Make (Ord) = struct
let empty = []
let add k v m = ... (* sorted insert via Ord.compare *)
let find_opt / find / mem / remove / bindings / cardinal
end end
module Set = struct module Make (Ord) = struct
let empty = []
let mem / add / remove / elements / cardinal
end end
Sorted association list / sorted list backing — linear ops but
correct. Strong substrate-validation: Map.Make is a non-trivial
functor implemented entirely on top of the OCaml-on-SX evaluator.
os_type="SX", word_size=64, max_array_length, max_string_length,
executable_name="ocaml-on-sx", big_endian=false, unix=true,
win32=false, cygwin=false. Constants-only for now — argv/getenv_opt/
command would need host platform integration.
ocaml-hm-parse-type-src recognises primitive type names (int/bool/
string/float/unit), tyvars 'a, and simple parametric T list / T option.
Replaces the previous int-by-default placeholder in
ocaml-hm-register-type-def!.
So 'type tag = TStr of string | TInt of int' correctly registers
TStr : string -> tag and TInt : int -> tag. Pattern-match on tag
gives proper field types in the body. Multi-arg / function types
still fall back to a fresh tv.
Parser: when | follows a pattern inside parens, build (:por ALT1 ALT2
...). Eval: try alternatives, succeed on first match. Top-level |
remains the clause separator — parens-only avoids ambiguity without
lookahead.
Examples now work:
match n with | (1 | 2 | 3) -> 100 | _ -> 0
match c with | (Red | Green) -> 1 | Blue -> 2
module type S = sig DECLS end is parsed-and-discarded — sig..end
balanced skipping in parse-decl-module-type. AST (:module-type-def
NAME). Runtime no-op (signatures are type-level only).
Allows real OCaml programs with module type decls to parse and run
without stripping the sig blocks.
Parser: { f1 = pat; f2 = pat; ... } in pattern position emits
(:precord (FIELDNAME PAT)...). Mixed with the existing { in
expression position via the at-pattern-atom? whitelist.
Eval: :precord matches against a dict; required fields must be present
and each pat must match the field's value. Can mix literal+var:
'match { x = 1; y = y } with | { x = 1; y = y } -> y' matches only
when x is 1.
ocaml-hm-ctors is now a mutable list cell; user type-defs register
their constructors via ocaml-hm-register-type-def!. New
ocaml-type-of-program processes top-level decls in order:
- type-def: register ctors with the scheme inferred from PARAMS+CTORS
- def/def-rec: generalize and bind in the type env
- exception-def: no-op for typing
- expr: return inferred type
Examples:
type color = Red | Green | Blue;; Red : color
type shape = Circle of int | Square of int;;
let area s = match s with
| Circle r -> r * r
| Square s -> s * s;;
area : shape -> Int
Caveat: ctor arg types parsed as raw source strings; registry defaults
to int for any single-arg ctor. Proper type-source parsing pending.
ocaml-infer-let-rec pre-binds the function name to a fresh tv before
inferring rhs (which may recursively call the name), unifies the
inferred rhs type with the tv, generalizes, then infers body.
Builtin env types :: : 'a -> 'a list -> 'a list and @ : 'a list ->
'a list -> 'a list — needed because :op compiles to (:app (:app (:var
OP) L) R) and previously these var lookups failed.
Examples now infer:
let rec fact n = if ... in fact : Int -> Int
let rec len lst = ... in len : 'a list -> Int
let rec map f xs = ... in map : ('a -> 'b) -> 'a list -> 'b list
1 :: [2; 3] : Int list
let rec sum lst = ... in sum [1;2;3] : Int
Scoreboard refreshed: 358/358 across 14 suites.
ocaml-hm-ctor-env registers None/Some : 'a -> 'a option, Ok/Error :
'a -> ('a, 'b) result. :con NAME instantiates the scheme; :pcon NAME
ARG-PATS walks arg patterns through the constructor's arrow type,
unifying each.
Pretty-printer renders 'Int option' and '(Int, 'b) result'.
Examples now infer:
fun x -> Some x : 'a -> 'a option
match Some 5 with | None -> 0 | Some n -> n : Int
fun o -> match o with | None -> 0 | Some n -> n : Int option -> Int
Ok 1 : (Int, 'b) result
Error "oops" : ('a, String) result
User type-defs would extend the registry — pending.
ocaml-infer-pat covers :pwild, :pvar, :plit, :pcons, :plist, :ptuple,
:pas. Returns {:type T :env ENV2 :subst S} where ENV2 has the pattern's
bound names threaded through.
ocaml-infer-match unifies each clause's pattern type with the scrutinee,
runs the body in the env extended with pattern bindings, and unifies
all body types via a fresh result tv.
Examples:
fun lst -> match lst with | [] -> 0 | h :: _ -> h : Int list -> Int
match (1, 2) with | (a, b) -> a + b : Int
Constructor patterns (:pcon) fall through to a fresh tv for now —
proper handling needs a ctor type registry from 'type' declarations.
compare is a host builtin returning -1/0/1 (Stdlib.compare semantics)
deferred to host SX </>. List.sort is insertion-sort in OCaml: O(n²)
but works correctly. List.stable_sort = sort.
Tested: ascending int sort, descending via custom comparator (b - a),
empty list, string sort.
Backing store is a one-element list cell holding a SX dict; keys
coerced to strings via str so int/string keys work uniformly. API:
create, add, replace, find, find_opt, mem, length.
_hashtbl_create / _hashtbl_add / _hashtbl_replace / _hashtbl_find_opt /
_hashtbl_mem / _hashtbl_length primitives wired in eval.sx; OCaml-side
Hashtbl module wraps them in lib/ocaml/runtime.sx.
Tuple type (hm-con "*" TYPES); list type (hm-con "list" (TYPE)).
ocaml-infer-tuple threads substitution through each item left-to-right.
ocaml-infer-list unifies all items with a fresh 'a (giving 'a list for
empty []).
Pretty-printer renders 'Int * Int' for tuples and 'Int list' for lists,
matching standard OCaml notation.
Examples:
fun x y -> (x, y) : 'a -> 'b -> 'a * 'b
fun x -> [x; x] : 'a -> 'a list
[] : 'a list
