A kept when answers an Option, get is a checked lookup over arrays, slices, Vecs and dyn, and if let reads as a two-arm match in both syntaxes.
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TODO.org
18
TODO.org
@ -10,15 +10,15 @@ pointing at it. A CANCELLED entry carries the one-line reason, because an idea
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rejected without a record is an idea that gets re-proposed.
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* Language surface
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** NEXT if let
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Decided 2026-09-26 (126), Rust's spelling: =if let Some(g) = left= plus a block tests
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the pattern and binds =g= in that block only; =elif=/=else= follow as for =if=. Any
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=match= pattern may stand where =Some(g)= is. Reads to a two-arm =match=.
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** NEXT when as a value, and get as a checked lookup
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Decided 2026-09-26 (125): a =when= whose value is used gives =Option(T)=, =Some= of its
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body when the test holds and =None= otherwise; as a statement it is unchanged.
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=get(xs, i, …)= on an array, slice or Vec gives =Option(T)= instead of trapping on an
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index out of range (negative included), one index per dimension. Both typed and dyn.
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** DONE if let
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CLOSED: [2026-09-26]
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=(if-let [P v] then else)= in paren syntax; an elif chain is the else. With no else it
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is a statement, not an Option. Rules out a plain name or =_= as the pattern (use =let=).
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** DONE when as a value, and get as a checked lookup
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CLOSED: [2026-09-26]
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Every one-armed =if= is a =when=; kept, it is =Option(T)=, nested over an Option body
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(Rust's =bool::then=), and body-or-nil where a dyn is wanted. A =_=-inferred return's
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last form is not kept. =get= over dyn text or vec is nil when out of range; =.field= still traps.
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** NEXT str and String
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Decided 2026-09-25: the typed read-only text is =str= (the rename from =string= is
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@ -102,7 +102,7 @@ fine here. Brackets and strings are still paired."
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;; `header_follow' in lib/indent_reader.ml: the words a statement starts with.
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(defconst flan-fln--header-words
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'("fn" "fn-" "def" "once" "const" "struct" "union" "data" "enum" "import"
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"if" "elif" "else" "while" "until" "for" "match" "let" "return" "break"
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"if" "when" "elif" "else" "while" "until" "for" "match" "let" "return" "break"
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"continue" "defer" "handler-case" "handler-bind" "restart-case" "on"
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"restart" "quote" "macro" "type" "class" "generic" "multi" "method"))
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@ -111,7 +111,7 @@ fine here. Brackets and strings are still paired."
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;; when it is the one-line `fn f(x) = e'; `if' does not when it is the one-line
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;; `if c then a else b'.
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(defconst flan-fln--opener-words
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'("fn" "fn-" "struct" "union" "data" "enum" "if" "elif" "else" "while"
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'("fn" "fn-" "struct" "union" "data" "enum" "if" "when" "elif" "else" "while"
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"until" "for" "match" "defer" "handler-case" "handler-bind"
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"restart-case" "on" "restart" "quote" "macro" "class" "multi" "method"))
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@ -409,7 +409,7 @@ and a call ending in `:'."
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(save-excursion
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(goto-char v)
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(or (looking-at "\\(?:match\\|handler-case\\|handler-bind\\|restart-case\\)\\(?:[ \t]\\|$\\)")
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(and (looking-at "if[ \t]") (not (flan-fln--then l)))
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(and (looking-at "\\(?:if\\|when\\)[ \t]") (not (flan-fln--then l)))
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(flan-fln--lambda-header-p v end))))))
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;;; Statements
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@ -1250,7 +1250,7 @@ Before it at the same level, else out to the line that owns this block."
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(not (save-excursion
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(goto-char w-end)
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(looking-at "[ \t]+[^][ \t\n(){},;\":]+("))))
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((member w '("if" "elif")) (not (flan-fln--then start)))
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((member w '("if" "when" "elif")) (not (flan-fln--then start)))
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(t t)))))
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;; `let r = match n', `x = if c', `fn f(x) = match x', a lambda
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;; header: the value goes on under the line.
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@ -1758,6 +1758,9 @@ lambda or a `Fn(...)' type, and not after a match arm's."
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;; The words inside a line: `for i in range(n)', `if c then a else b', a
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;; `where' constraint.
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("[ \t]\\(then\\|else\\|in\\|where\\)[ \t]" 1 font-lock-keyword-face)
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;; `if let Some(g) = x', and a value's `if' or `when', `x = when c then a'.
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("\\_<if[ \t]+\\(let\\)[ \t]" 1 font-lock-keyword-face)
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("[ \t=(,]\\(if\\|when\\)[ \t]" 1 font-lock-keyword-face)
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;; The operator words.
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("\\_<\\(and\\|or\\|not\\)\\_>" 1 font-lock-keyword-face)
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(,(concat "\\_<" (regexp-opt flan--constants t) "\\_>")
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@ -128,7 +128,7 @@
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"Forms that introduce a top-level name.")
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(defconst flan--special
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'("quote" "do" "let" "if" "when" "cond" "and" "or"
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'("quote" "do" "let" "if" "if-let" "when" "cond" "and" "or"
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"while" "until" "break" "continue" "return" "set"
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"array" "array-fill" "array-gen" "the" "match" "fn" "dotimes" "loop" "recur"
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"defer" "some" "try" "signal" "error"
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@ -580,6 +580,7 @@ For `syntax-propertize-function'."
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("handler-case" . 1)
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;; Test first, body after.
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("if" . 1)
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("if-let" . 1)
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("when" . 1)
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("unless" . 1)
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("while" . 1)
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@ -858,6 +858,20 @@ defconst(k, 3)
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(test-flan-fln--tabs "let colors =\n|" 1) 2)
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(test-flan-fln--is "but not after a one-line fn"
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(test-flan-fln--tabs "fn f() -> i32 = 1\n|" 1) 0)
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(test-flan-fln--is "after if let, one level deeper"
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(test-flan-fln--tabs "fn f() -> ()\n if let Some(g) = o\n|" 1) 4)
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(test-flan-fln--is "and after a when with a block"
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(test-flan-fln--tabs "fn f() -> ()\n when a > 1\n|" 1) 4)
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(test-flan-fln--is "but not after a one-line when"
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(test-flan-fln--tabs "fn f() -> ()\n when a then b()\n|" 1) 2)
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(test-flan-fln--in "fn f() -> ()\n if let Some(g) = o\n g\n let w = when a then 1\n when b\n c()\n"
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(font-lock-ensure)
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(let ((face (lambda (needle)
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(save-excursion (goto-char (point-min)) (search-forward needle)
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(get-text-property (match-beginning 0) 'face)))))
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(test-flan-fln--is "if let's let is a keyword" (funcall face "let Some") 'font-lock-keyword-face)
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(test-flan-fln--is "a value's when is a keyword" (funcall face "when a") 'font-lock-keyword-face)
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(test-flan-fln--is "and so is a statement's" (funcall face "when b") 'font-lock-keyword-face)))
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(test-flan-fln--is "else goes to its if's column, whatever the depth"
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(test-flan-fln--tabs "if a\n if b\n c\n |else" 1) 2)
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(test-flan-fln--is "and a second TAB to the outer if's"
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@ -79,6 +79,10 @@ and expr_kind =
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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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(* (if-let [(Some g) left] then else) — [if let Some(g) = left] in .fln.
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A two-arm [match]: the arm is the pattern with [then] as its body, and
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the else is the [_] arm. With no else it is a statement. *)
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| IfLet of expr * arm * expr option
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| Struct of string * (string * expr) list (* (Cursor {.src s}) *)
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(* {.src s .pos 0} with no type written in front of it. The fields alone do
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not name a type, so this node carries no name and is only checkable where
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@ -465,6 +469,7 @@ let map_children f (e : expr) : expr =
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| Field (x, n) -> Field (ex x, n)
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| Call (fn, args) -> Call (ex fn, List.map ex args)
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| Match (s, arms) -> Match (ex s, List.map arm arms)
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| IfLet (s, a, e) -> IfLet (ex s, arm a, Option.map ex e)
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| Struct (n, fs) -> Struct (n, List.map (fun (n, v) -> (n, ex v)) fs)
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| Bare fs -> Bare (List.map (fun (n, v) -> (n, ex v)) fs)
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| MapLit (tag, kvs) -> MapLit (tag, List.map (fun (k, v) -> (ex k, ex v)) kvs)
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@ -538,6 +543,8 @@ and step_expr fn (e : expr) : expr =
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| Dotimes (l, n, b, es) -> { e with e = Dotimes (l, n, b, step_body fn es) }
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| Match (sc, arms) ->
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{ e with e = Match (sc, List.map (fun a -> { a with body = step_body fn a.body }) arms) }
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| IfLet (sc, a, b) ->
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{ e with e = IfLet (sc, { a with body = step_body fn a.body }, Option.map branch b) }
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| _ -> e
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let instrument_step ?(fn = "step-point") (ds : decl list) : decl list option =
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338
lib/check.ml
338
lib/check.ml
@ -863,6 +863,13 @@ type ctx = {
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and a [match] arm. Everything else is therefore non-tail by construction,
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and no walk has to enumerate the cases that are not. *)
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mutable tail : bool;
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(* True where this form's value is kept: a [let] binding's value, and what
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a block's last form, an [if]'s arms and a [match]'s arms inherit from
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the form they stand in. Read and withdrawn at the top of [check] as
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[tail] is. Only a one-armed [if] ([when]) asks: used, it answers an
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Option; not, it is a statement. [want] alone cannot say, since a
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statement and an unannotated [let] value both arrive with none. *)
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mutable used : bool;
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(* True inside a [defer]'s forms. A defer is the cleanup a transfer runs on
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its way out (§5), so a transfer *starting* there has no answer: this
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function's defers are already half run and the first transfer's target is
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@ -4780,7 +4787,7 @@ let with_recovery env ~on f =
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let invented_ctx env ret =
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{ env; ret; slots = 0; slot_tys = []; slot_names = []; scope = [];
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defers = []; defer_slot = None; outer = []; outer_what = None; caught = []; place_ok = false; envslot = None; parent = None; in_frames = None; loops = []; tail = false;
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defers = []; defer_slot = None; outer = []; outer_what = None; caught = []; place_ok = false; envslot = None; parent = None; in_frames = None; loops = []; tail = false; used = false;
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in_defer = false; defer_ok = false; defer_block = "a nested form";
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owner = "<none>" }
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@ -5428,7 +5435,8 @@ let truthy_depth = ref 0
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it — the square of a refused or/and chain's length. *)
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let if_failed :
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(Loc.t,
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Ast.expr * ((string * binding) list * Types.t) * Types.t option * Loc.diag)
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Ast.expr * ((string * binding) list * Types.t) * (Types.t option * bool)
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* Loc.diag)
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Hashtbl.t =
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Hashtbl.create 16
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let if_depth = ref 0
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@ -5657,6 +5665,8 @@ and check_value ctx ?want (e : Ast.expr) : Tast.expr =
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it unless the arm below hands it on deliberately. *)
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let tail = ctx.tail in
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ctx.tail <- false;
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let used = ctx.used in
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ctx.used <- false;
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match e.Ast.e with
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(* A negative literal in a generic body, at an instantiation that made it
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unsigned. The cast the ordinary refusal names would be wrong at every
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@ -5837,13 +5847,13 @@ and check_value ctx ?want (e : Ast.expr) : Tast.expr =
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in
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check ctx ?want { e with Ast.e = Ast.Int n }
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| Ast.Var name -> var ctx loc ~want name
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| Ast.Do body -> ctx.tail <- tail; block ctx ?want loc body
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| Ast.Do body -> ctx.tail <- tail; ctx.used <- used; block ctx ?want loc body
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(* [defer_ok] rides through: a [let] at the top level of a function body has
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exactly the function's extent, and so does a [let] nested inside one.
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[tail] rides through for the same shape of reason: a [recur] written as
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the last form of a [let] inside a loop body is in the loop's tail. *)
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| Ast.Let (bs, body) -> check_let ctx ~tail ?want ~defer_ok loc bs body
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| Ast.If (c, t, e') -> check_if ctx ~tail ?want loc c t e'
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| Ast.Let (bs, body) -> check_let ctx ~tail ~used ?want ~defer_ok loc bs body
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| Ast.If (c, t, e') -> check_if ctx ~tail ~used ?want loc c t e'
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| Ast.While (label, c, body) ->
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(* The condition is part of the loop even though it is written outside the
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braces — emit puts it in the header block, so it is re-evaluated at the
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@ -6039,7 +6049,9 @@ and check_value ctx ?want (e : Ast.expr) : Tast.expr =
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| Ast.ArrayFill (dims, v) -> check_array_fill ctx ~want loc dims v
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| Ast.ArrayGen (dims, f) -> check_array_gen ctx ~want loc dims f
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| Ast.The (t, v) -> check_the ctx ~want loc t v
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| Ast.Match (scrutinee, arms) -> check_match ctx ~tail ?want loc scrutinee arms
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| Ast.Match (scrutinee, arms) -> check_match ctx ~tail ~used ?want loc scrutinee arms
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| Ast.IfLet (scrutinee, arm, els) ->
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check_if_let ctx ~tail ~used ?want loc scrutinee arm els
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(* Constant integer arithmetic where a type variable is wanted is folded to
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the literal it computes first, so [(+ x (+ 1 2))] is admitted wherever
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[(+ x 3)] is. The instantiation re-checks the form unfolded, at a concrete
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@ -6463,20 +6475,24 @@ and block ctx ?want ?(defer_ok = false) loc body =
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match body with
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(* Withdrawn here too. An empty body has no last form to be the tail, so
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leaving the permission set would hand it to whatever is checked next. *)
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| [] -> ctx.tail <- false; expect ctx loc ~want (unit_at loc)
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| [] -> ctx.tail <- false; ctx.used <- false; expect ctx loc ~want (unit_at loc)
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| _ ->
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(* A block's tail is its last form and nothing else. Callers that must not
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pass one on need do nothing: [check] withdrew it before they were
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reached, so [tail] is already false here for all of them. *)
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let tail = ctx.tail in
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let used = ctx.used in
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ctx.used <- false;
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let rec go = function
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| [ last ] ->
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ctx.defer_ok <- defer_ok;
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ctx.tail <- tail;
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ctx.used <- used;
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let l = check ctx ?want last in [ l ], l.Tast.ty
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| x :: rest ->
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ctx.defer_ok <- defer_ok;
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ctx.tail <- false;
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ctx.used <- false;
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let x = check ctx x in
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let rest, ty = go rest in x :: rest, ty
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| [] -> assert false
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@ -7090,12 +7106,13 @@ and defer_counter_zero slot loc =
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(* [defer_ok] says whether *this* let has the function's extent. If it does, so
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does every form in its body, including a nested let — which is why the flag
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is handed to the body rather than consumed here. *)
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and check_let ctx ?(tail = false) ?want ?(defer_ok = false) loc bs body =
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and check_let ctx ?(tail = false) ?(used = false) ?want ?(defer_ok = false) loc bs body =
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scoped ctx (fun () ->
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let bs =
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map_lr
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(fun (b : Ast.binding) ->
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let want = Option.map (resolve ctx.env) b.Ast.bty in
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ctx.used <- true;
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let v = check ctx ?want b.Ast.bval in
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(match v.Tast.ty with
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(* A refused initialiser, already reported: the name is bound to
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@ -7112,6 +7129,7 @@ and check_let ctx ?(tail = false) ?want ?(defer_ok = false) loc bs body =
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in
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(* After the bindings, because checking each of them withdrew it. *)
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ctx.tail <- tail;
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ctx.used <- used;
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let body = block ctx ?want ~defer_ok loc body in
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mk loc body.Tast.ty (Tast.Let (bs, [ body ])))
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@ -7583,14 +7601,14 @@ and check_truthy_once ctx c =
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with Loc.Error d -> refuse_or_poison ctx.env loc d))
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| exception Loc.Error _ -> check ctx ~want:Types.Bool c
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and check_if ctx ?(tail = false) ?want loc c t e =
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and check_if ctx ?(tail = false) ?(used = false) ?want loc c t e =
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if ctx.env.recovering && ctx.env.speculating = 0 then
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check_if_once ctx ~tail ?want loc c t e
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check_if_once ctx ~tail ~used ?want loc c t e
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else
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match
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List.find_opt
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(fun (n, (sc, r), w, _) ->
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n == c && r == ctx.ret && w = want && same_scope sc ctx.scope)
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n == c && r == ctx.ret && w = (want, used) && same_scope sc ctx.scope)
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(Hashtbl.find_all if_failed c.Ast.loc)
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with
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| Some (_, _, _, d) -> raise (Loc.Error d)
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@ -7602,23 +7620,20 @@ and check_if ctx ?(tail = false) ?want loc c t e =
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decr if_depth;
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if !if_depth = 0 then Hashtbl.reset if_failed)
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(fun () ->
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try check_if_once ctx ~tail ?want loc c t e
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try check_if_once ctx ~tail ~used ?want loc c t e
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with Loc.Error d as ex ->
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Hashtbl.add if_failed c.Ast.loc (c, (scope, ctx.ret), want, d);
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Hashtbl.add if_failed c.Ast.loc (c, (scope, ctx.ret), (want, used), d);
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raise ex)
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and check_if_once ctx ~tail ?want loc c t e =
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and check_if_once ctx ~tail ~used ?want loc c t e =
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let c = check_truthy ctx c in
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(* Both arms are the tail, and a one-armed [if] counts: [(when c (recur ...))]
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is how nearly every loop is written, and the branch is still the last
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thing the body does. *)
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let in_tail f = ctx.tail <- tail; f () in
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thing the body does. Both arms are kept when the [if] is. *)
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let in_tail f = ctx.tail <- tail; ctx.used <- used; f () in
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match e with
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| None ->
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(* A one-armed if produces Unit whatever the branch evaluates to: there is
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no value on the missing side. `when` desugars to this. *)
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let t = branch ctx (fun () -> in_tail (fun () -> check ctx t)) in
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expect ctx loc ~want (mk loc Types.Unit (Tast.If (c, t, unit_at loc)))
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| None -> check_when ctx ~used ?want loc c (fun ?want () ->
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branch ctx (fun () -> in_tail (fun () -> check ctx ?want t)))
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(* Two literal arms meet at the wider of their own types, as two literal
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elements of an array do: [(if c 1 2.5)] is an f64. *)
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| Some e
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@ -7813,6 +7828,48 @@ and check_if_once ctx ~tail ?want loc c t e =
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in
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mk loc ty (Tast.If (c, t, e))
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(* A one-armed [if], which [when] is. As a statement it is Unit whatever its
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branch evaluates to. Kept — a [let]'s value, an argument, a return, or
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anything else with a type wanted of it — it answers (Option T): [Some] of
|
||||
the branch when the test held and [None] when it did not. A branch that
|
||||
is already an Option is not flattened: the answer is (Option (Option T)),
|
||||
Rust's [bool::then], so [None] from the branch and a failed test stay two
|
||||
answers.
|
||||
|
||||
Dyn has no Option. Where a dyn is wanted, or the branch is a dyn, a false
|
||||
test answers nil and a true one the branch's value — one absence, as a
|
||||
dyn map's [get] has.
|
||||
|
||||
A branch with no value (Unit) or none at all (Never) keeps the statement's
|
||||
Unit, so what is refused about binding one is refused as before. *)
|
||||
and check_when ctx ~used ?want loc c
|
||||
(branch_at : ?want:Types.t -> unit -> Tast.expr) =
|
||||
let stmt t = expect ctx loc ~want (mk loc Types.Unit (Tast.If (c, t, unit_at loc))) in
|
||||
let nil () = rt loc Types.Dyn "flan_dyn_nil" [] in
|
||||
let valueless (t : Tast.expr) =
|
||||
match t.Tast.ty with Types.Unit | Types.Never -> true | _ -> false
|
||||
in
|
||||
match want with
|
||||
| Some (Types.Unit | Types.Never) -> stmt (branch_at ())
|
||||
| Some Types.Dyn ->
|
||||
let t = branch_at ~want:Types.Dyn () in
|
||||
mk loc Types.Dyn (Tast.If (c, t, nil ()))
|
||||
| Some (Types.Option inner) ->
|
||||
let t = branch_at ~want:inner () in
|
||||
let oty = Types.Option inner in
|
||||
let some = if t.Tast.ty = Types.Never then t else mk loc oty (Tast.Some_ t) in
|
||||
mk loc oty (Tast.If (c, some, mk loc oty Tast.None_))
|
||||
| None when not used -> stmt (branch_at ())
|
||||
| _ ->
|
||||
let t = branch_at () in
|
||||
if valueless t then stmt t
|
||||
else if Types.equal t.Tast.ty Types.Dyn then
|
||||
expect ctx loc ~want (mk loc Types.Dyn (Tast.If (c, t, nil ())))
|
||||
else
|
||||
let oty = Types.Option t.Tast.ty in
|
||||
expect ctx loc ~want
|
||||
(mk loc oty (Tast.If (c, mk loc oty (Tast.Some_ t), mk loc oty Tast.None_)))
|
||||
|
||||
(* The type two literals meet at, each at its own type — a wide integer at
|
||||
u64, which is the only type that holds one. *)
|
||||
and literal_join ctx (a : Ast.expr) (b : Ast.expr) =
|
||||
@ -8856,7 +8913,12 @@ and check_array_gen ctx ~want loc dims f =
|
||||
(array_build ctx loc ns elem ~pre:[ (fs, f) ]
|
||||
~element:(fun idxs -> mk loc elem (Tast.CallPtr (fv, idxs))))
|
||||
|
||||
and check_match ctx ?(tail = false) ?want loc scrutinee arms =
|
||||
and check_match ctx ?(tail = false) ?(used = false) ?(stmt = false) ?want loc
|
||||
scrutinee arms =
|
||||
(* [stmt] is an [if let] with no else: a statement, Unit whatever its arm
|
||||
answers, as a one-armed [if] is when nothing keeps it. *)
|
||||
let used = used && not stmt in
|
||||
let want = if stmt then None else want in
|
||||
let s = check ctx scrutinee in
|
||||
(* What the arms are alternatives over. An [Option] is a two-case data type
|
||||
wearing a special coat, so the two shapes below are the same shape: a set
|
||||
@ -9260,6 +9322,7 @@ and check_match ctx ?(tail = false) ?want loc scrutinee arms =
|
||||
(* Every arm is the tail, exactly as an [if]'s two arms are.
|
||||
Restored here because checking the scrutinee withdrew it. *)
|
||||
ctx.tail <- tail;
|
||||
ctx.used <- used;
|
||||
let arm = (a, ctor, binds) in
|
||||
let body =
|
||||
if free && !want <> None && not (literal_arm arm) then
|
||||
@ -9306,7 +9369,12 @@ and check_match ctx ?(tail = false) ?want loc scrutinee arms =
|
||||
| Error _ -> at !want ())
|
||||
else block ctx ?want:!want a.Ast.aloc a.Ast.body
|
||||
in
|
||||
(if body.Tast.ty <> Types.Never then
|
||||
let body =
|
||||
if stmt && body.Tast.ty <> Types.Unit && body.Tast.ty <> Types.Never
|
||||
then mk body.Tast.loc Types.Unit (Tast.Do [ body; unit_at body.Tast.loc ])
|
||||
else body
|
||||
in
|
||||
(if body.Tast.ty <> Types.Never && not stmt then
|
||||
match !want with
|
||||
| None -> want := Some body.Tast.ty
|
||||
| Some w when free ->
|
||||
@ -9400,7 +9468,10 @@ and check_match ctx ?(tail = false) ?want loc scrutinee arms =
|
||||
(String.concat ", " missing)
|
||||
(if List.length missing = 1 then "has" else "have")
|
||||
(if List.length missing = 1 then "it" else "them");
|
||||
let ty = match !want with Some t -> t | None -> Types.Never in
|
||||
let ty =
|
||||
if stmt then Types.Unit
|
||||
else match !want with Some t -> t | None -> Types.Never
|
||||
in
|
||||
match subject with
|
||||
| `Option _ | `Data _ -> mk loc ty (Tast.Match (s, arms))
|
||||
| `Enum _ | `Bool | `Lit _ ->
|
||||
@ -9436,6 +9507,49 @@ and check_match ctx ?(tail = false) ?want loc scrutinee arms =
|
||||
in
|
||||
mk loc ty (Tast.Let ([ (slot, s) ], [ chain arms ]))
|
||||
|
||||
(* [if let P = v] — (if-let [P v] then else) — is the two-arm match
|
||||
[(match v P then _ else)]. With no else it is a statement, Unit whatever
|
||||
[then] answers, as a one-armed [if] is.
|
||||
|
||||
A pattern that cannot fail — [_], or a plain name, which is a name to bind
|
||||
and not a case — tests nothing, and is refused toward [let]. A bare name is
|
||||
a case when some data type, Option or bool has a case of that name, or it
|
||||
names an enum member through its enum. *)
|
||||
and check_if_let ctx ~tail ~used ?want loc scrutinee (arm : Ast.arm) els =
|
||||
let fln = fln_source loc in
|
||||
let is_case n =
|
||||
List.mem n [ "None"; "Some"; "true"; "false" ]
|
||||
|| String.contains n '.'
|
||||
|| Hashtbl.fold
|
||||
(fun _ u acc -> acc || Tast.case_index u n <> None)
|
||||
ctx.env.datas false
|
||||
in
|
||||
let irrefutable name =
|
||||
match name with
|
||||
| Some n ->
|
||||
Loc.failk "check/if-let-irrefutable" arm.Ast.aloc
|
||||
"the pattern %s is a plain name, which always matches, so this if let \
|
||||
has nothing to test. Bind the value with %s"
|
||||
n
|
||||
(if fln then Printf.sprintf "let %s = ..." n
|
||||
else Printf.sprintf "(let [%s ...] ...)" n)
|
||||
| None ->
|
||||
Loc.failk "check/if-let-irrefutable" arm.Ast.aloc
|
||||
"the pattern _ always matches, so this if let has nothing to test. \
|
||||
Use the value directly, or match on it"
|
||||
in
|
||||
(match arm.Ast.pat with
|
||||
| Ast.Pwild -> irrefutable None
|
||||
| Ast.Pctor (n, []) when not (is_case n) -> irrefutable (Some n)
|
||||
| _ -> ());
|
||||
let wild body = { Ast.pat = Ast.Pwild; body; aloc = loc } in
|
||||
match els with
|
||||
| Some e ->
|
||||
check_match ctx ~tail ~used ?want loc scrutinee [ arm; wild [ e ] ]
|
||||
| None ->
|
||||
expect ctx loc ~want
|
||||
(check_match ctx ~tail ~stmt:true loc scrutinee [ arm; wild [] ])
|
||||
|
||||
(* ── Places ────────────────────────────────────────────────────────── *)
|
||||
|
||||
(* The fields a name has, whether it is a struct or an untagged union. The two
|
||||
@ -10702,6 +10816,141 @@ and vec_at ctx loc (target : Tast.expr) (idx : Ast.expr list) =
|
||||
fail loc
|
||||
"a Vec takes exactly one index, as (at v i)"
|
||||
|
||||
(* [(get xs i ...)] over an array, a slice, a string or a Vec: the element
|
||||
as [(Some e)], or [None] when any index is out of range, negative
|
||||
included, where [at] would trap. One index per dimension, as [at] takes.
|
||||
|
||||
The indices are evaluated once, left to right, before any test. An array's
|
||||
length is static, so the array itself is read once and is not copied; a
|
||||
slice's, a string's or a Vec's is read off the value, so that value is
|
||||
put in a slot first unless it is already a name. Each level is tested
|
||||
before the next is reached, because a Vec of Vecs has no inner length to
|
||||
test until the outer index is known to be in range. The element is then
|
||||
read by [at] as usual, whose own check can no longer fail. *)
|
||||
and checked_get ctx ~want loc (target : Tast.expr) (idx : Ast.expr list) =
|
||||
let rec result ty = function
|
||||
| [] -> ty
|
||||
| (i : Ast.expr) :: rest ->
|
||||
(match ty with
|
||||
| Types.Array (_, t) | Types.Slice (_, t) | Types.Vec t -> result t rest
|
||||
| Types.String -> result (Types.Int Types.U8) rest
|
||||
| other ->
|
||||
fail i.Ast.loc
|
||||
"get takes an array, a slice, a string, a Vec, a Map or a dyn, and \
|
||||
%s cannot be indexed" (tyname i.Ast.loc other))
|
||||
in
|
||||
let oty = Types.Option (result target.Tast.ty idx) in
|
||||
let none () = mk loc oty Tast.None_ in
|
||||
let is_name (e : Tast.expr) =
|
||||
match e.Tast.e with Tast.Local _ | Tast.Global _ -> true | _ -> false
|
||||
in
|
||||
(* A value a call answered is bound before the indices run, so the target
|
||||
is still evaluated first. *)
|
||||
let pre = ref [] in
|
||||
let target =
|
||||
match target.Tast.e with
|
||||
| Tast.Call _ | Tast.CallPtr _ ->
|
||||
let s = fresh_slot ctx target.Tast.ty in
|
||||
pre := [ (s, target) ];
|
||||
mk loc target.Tast.ty (Tast.Local s)
|
||||
| _ -> target
|
||||
in
|
||||
let islots =
|
||||
map_lr
|
||||
(fun (i : Ast.expr) ->
|
||||
let v = index_expr ctx i in
|
||||
let s = fresh_slot ctx index_ty in
|
||||
(s, v))
|
||||
idx
|
||||
in
|
||||
let ivar (s, _) = mk loc index_ty (Tast.Local s) in
|
||||
let i32 k = mk loc index_ty (Tast.Int (k, Types.I32)) in
|
||||
let within i len =
|
||||
let ge = mk loc Types.Bool (Tast.Prim (Tast.Ge, [ i; i32 0L ])) in
|
||||
let lt = mk loc Types.Bool (Tast.Prim (Tast.Lt, [ i; len ])) in
|
||||
mk loc Types.Bool (Tast.If (ge, lt, mk loc Types.Bool (Tast.Bool false)))
|
||||
in
|
||||
(* The value reached so far is [base] indexed by [path], innermost last. *)
|
||||
let reached base path ty =
|
||||
if path = [] then base
|
||||
else mk loc ty (Tast.Prim (Tast.At, base :: List.rev path))
|
||||
in
|
||||
(* A value whose length is read as well as indexed, in a slot unless it is
|
||||
a name already. *)
|
||||
let named cur k =
|
||||
if is_name cur then k cur
|
||||
else
|
||||
let s = fresh_slot ctx cur.Tast.ty in
|
||||
mk loc oty
|
||||
(Tast.Let ([ (s, cur) ], [ k (mk loc cur.Tast.ty (Tast.Local s)) ]))
|
||||
in
|
||||
let rec go base path ty = function
|
||||
| [] -> mk loc oty (Tast.Some_ (reached base path ty))
|
||||
| i :: rest ->
|
||||
let i = ivar i in
|
||||
(match ty with
|
||||
| Types.Array (n, t) ->
|
||||
mk loc oty (Tast.If (within i (i32 n), go base (i :: path) t rest, none ()))
|
||||
| Types.Slice _ | Types.String ->
|
||||
let t =
|
||||
match ty with Types.Slice (_, t) -> t | _ -> Types.Int Types.U8
|
||||
in
|
||||
named (reached base path ty) (fun cur ->
|
||||
let len = mk loc index_ty (Tast.Prim (Tast.Len, [ cur ])) in
|
||||
mk loc oty (Tast.If (within i len, go cur [ i ] t rest, none ())))
|
||||
| Types.Vec t ->
|
||||
named (reached base path ty) (fun cur ->
|
||||
let n = rt loc (Types.Int Types.I64) "flan_vec_len" [ cur; here loc ] in
|
||||
let len = mk loc index_ty (Tast.Prim (Tast.Cast index_ty, [ n ])) in
|
||||
let p =
|
||||
rt loc (Types.Ptr (Types.Mut, t)) "flan_vec_at"
|
||||
[ cur; i; size_of loc t; here loc ]
|
||||
in
|
||||
mk loc oty
|
||||
(Tast.If (within i len, go (mk loc t (Tast.Deref p)) [] t rest,
|
||||
none ())))
|
||||
| _ -> assert false)
|
||||
in
|
||||
expect ctx loc ~want
|
||||
(mk loc oty (Tast.Let (!pre @ islots, [ go target [] target.Tast.ty islots ])))
|
||||
|
||||
(* [(get d k ...)] over a dyn: a map's value at the key, a vec's or a text's
|
||||
element at the index, or nil when there is none — dyn has no Option. More
|
||||
than one key walks a level per key, and a nil level answers nil. *)
|
||||
and dyn_get ctx ~want loc (target : Tast.expr) (keys : Ast.expr list) =
|
||||
let nil () = rt loc Types.Dyn "flan_dyn_nil" [] in
|
||||
let one v k = rt loc Types.Dyn "flan_dyn_get_at" [ v; k; here loc ] in
|
||||
let keys =
|
||||
map_lr
|
||||
(fun k -> (fresh_slot ctx Types.Dyn, check ctx ~want:Types.Dyn k))
|
||||
keys
|
||||
in
|
||||
let kvar (s, _) = mk loc Types.Dyn (Tast.Local s) in
|
||||
let rec go v = function
|
||||
| [] -> v
|
||||
| k :: rest when rest = [] -> one v (kvar k)
|
||||
| k :: rest ->
|
||||
let s = fresh_slot ctx Types.Dyn in
|
||||
let sv = mk loc Types.Dyn (Tast.Local s) in
|
||||
let is_nil =
|
||||
mk loc Types.Bool
|
||||
(Tast.Prim (Tast.Ne,
|
||||
[ rt loc (Types.Int Types.I32) "flan_dyn_is_nil" [ sv ];
|
||||
mk loc (Types.Int Types.I32) (Tast.Int (0L, Types.I32)) ]))
|
||||
in
|
||||
mk loc Types.Dyn
|
||||
(Tast.Let ([ (s, one v (kvar k)) ],
|
||||
[ mk loc Types.Dyn (Tast.If (is_nil, nil (), go sv rest)) ]))
|
||||
in
|
||||
match keys with
|
||||
| [ (_, k) ] -> expect ctx loc ~want (one target k)
|
||||
| _ ->
|
||||
let ts = fresh_slot ctx Types.Dyn in
|
||||
expect ctx loc ~want
|
||||
(mk loc Types.Dyn
|
||||
(Tast.Let ((ts, target) :: keys,
|
||||
[ go (mk loc Types.Dyn (Tast.Local ts)) keys ])))
|
||||
|
||||
(* [(slice v)], [(slice v lo)] and [(slice v lo hi)] over a Vec — the arm for
|
||||
it is in [slice], and this is the half that differs from an array's.
|
||||
|
||||
@ -11932,20 +12181,29 @@ and named_call ?(qualified = false) ctx ~want loc name args =
|
||||
There is no allocation here and therefore no guard: a lookup that finds
|
||||
nothing is an answer, not a failure. *)
|
||||
| "get" ->
|
||||
arity ctx loc name 2 args;
|
||||
(match args with
|
||||
| target :: (_ :: _ :: _ as idx) ->
|
||||
(* Two indices or more: an array, a slice or a Vec, one per
|
||||
dimension, or a dyn walked a level per index. A map takes one key. *)
|
||||
let target = check_target ctx target in
|
||||
(match target.Tast.ty with
|
||||
| Types.Map _ ->
|
||||
fail loc "a map's get takes one key, as (get m k), and this has %d"
|
||||
(List.length idx)
|
||||
| Types.Dyn -> dyn_get ctx ~want loc target idx
|
||||
| _ -> checked_get ctx ~want loc target idx)
|
||||
| [ target; k ] ->
|
||||
let target = check_target ctx target in
|
||||
(match target.Tast.ty with
|
||||
| Types.Array _ | Types.Slice _ | Types.String | Types.Vec _ ->
|
||||
checked_get ctx ~want loc target [ k ]
|
||||
| Types.Dyn -> dyn_get ctx ~want loc target [ k ]
|
||||
| _ ->
|
||||
(* A dyn map's absence is nil, not None: the typed map can promise an
|
||||
(Option V) because V was written down, and a dyn map has nothing to
|
||||
write. nil is an ordinary dyn value the caller compares against —
|
||||
and (contains? m k) is the question to ask when nil might also be
|
||||
stored under the key. *)
|
||||
if target.Tast.ty = Types.Dyn then
|
||||
expect ctx loc ~want
|
||||
(rt loc Types.Dyn "flan_dyn_get"
|
||||
[ target; check ctx ~want:Types.Dyn k; here loc ])
|
||||
else begin
|
||||
let kt, vt = map_kv loc "get" target.Tast.ty in
|
||||
let k = check ctx ~want:kt k in
|
||||
(* Deferred, and the placeholder is [None] rather than [Unit]: this
|
||||
@ -11954,9 +12212,8 @@ and named_call ?(qualified = false) ctx ~want loc name args =
|
||||
if deferred_key ctx.env loc "get" kt then
|
||||
expect ctx loc ~want (mk loc (Types.Option vt) Tast.None_)
|
||||
else
|
||||
map_lookup ctx ~want loc "flan_map_get" target kt vt k
|
||||
end
|
||||
| _ -> assert false)
|
||||
map_lookup ctx ~want loc "flan_map_get" target kt vt k)
|
||||
| _ -> arity ctx loc name 2 args; assert false)
|
||||
|
||||
(* (keyword s) -> the interned dyn keyword named by the bytes, for a name
|
||||
that only exists at run time — a reader building :texture-path out of a
|
||||
@ -14216,7 +14473,7 @@ and trial ctx f =
|
||||
let[@warning "+9"] { env = _; ret = _; slots; slot_tys; slot_names; scope;
|
||||
defers; defer_slot; defer_ok; defer_block; outer = _;
|
||||
outer_what; caught; place_ok; envslot; parent = _;
|
||||
in_frames; loops; tail; in_defer;
|
||||
in_frames; loops; tail; used; in_defer;
|
||||
owner = _ } = ctx in
|
||||
let undo, keep = snapshot_env ctx.env in
|
||||
match speculate ctx.env f with
|
||||
@ -14229,7 +14486,8 @@ and trial ctx f =
|
||||
ctx.defer_ok <- defer_ok; ctx.defer_block <- defer_block;
|
||||
ctx.outer_what <- outer_what; ctx.in_frames <- in_frames;
|
||||
ctx.caught <- caught; ctx.place_ok <- place_ok; ctx.envslot <- envslot;
|
||||
ctx.loops <- loops; ctx.tail <- tail; ctx.in_defer <- in_defer;
|
||||
ctx.loops <- loops; ctx.tail <- tail; ctx.used <- used;
|
||||
ctx.in_defer <- in_defer;
|
||||
Error d
|
||||
| exception e -> keep (); raise e
|
||||
|
||||
@ -14590,10 +14848,13 @@ let builtins : (string * string * string) list =
|
||||
("put", "put [(Map K V) K V] ()",
|
||||
"Inserts or replaces. Unit rather than an error code, and \
|
||||
(set (get m k) v) is not map syntax.");
|
||||
("get", "get [(Map K V) K] (Option V)",
|
||||
("get", "get [(Map K V) K]|[collection i32 ...] (Option V)|(Option T)",
|
||||
"The value at the key, or None. Nothing signals here — a lookup that \
|
||||
finds nothing is an answer — and the value comes back as a copy of \
|
||||
its bytes.");
|
||||
its bytes. Over an array, a slice, a string or a Vec it is at that \
|
||||
answers None for an index out of range, negative included, one index \
|
||||
per dimension. Over a dyn it answers nil for an absent key or index, \
|
||||
and more keys walk a level each.");
|
||||
("map-remove", "map-remove [(Map K V) K] (Option V)",
|
||||
"Removes the entry and answers the value it held, or None if there was \
|
||||
none.");
|
||||
@ -15597,6 +15858,9 @@ let escaping_names ~returns (body : Ast.expr list) : string list =
|
||||
| Ast.Do es | Ast.Let (_, es) ->
|
||||
(match List.rev es with x :: _ -> tails x | [] -> ())
|
||||
| Ast.If (_, a, b) -> tails a; Option.iter tails b
|
||||
| Ast.IfLet (_, a, b) ->
|
||||
(match List.rev a.Ast.body with x :: _ -> tails x | [] -> ());
|
||||
Option.iter tails b
|
||||
| Ast.Match (_, arms) ->
|
||||
List.iter
|
||||
(fun (a : Ast.arm) ->
|
||||
|
||||
@ -5021,6 +5021,7 @@ declare void @flan_dyn_class_hook(ptr)
|
||||
declare i64 @flan_dyn_kw(ptr, i64)
|
||||
declare i64 @flan_dyn_map_get(i64, i64)
|
||||
declare i64 @flan_dyn_get(i64, i64, ptr, i64)
|
||||
declare i64 @flan_dyn_get_at(i64, i64, ptr, i64)
|
||||
declare void @flan_dyn_map_set(i64, i64, i64)
|
||||
declare i64 @flan_dyn_map_contains(i64, i64)
|
||||
declare i64 @flan_dyn_map_contains_at(i64, i64, ptr, i64)
|
||||
|
||||
@ -432,8 +432,19 @@ and list f h args =
|
||||
("fn(" ^ commas ps ^ ") => " ^ unit_text body, 0)
|
||||
| Form.Sym "if", [ c; a; b ] ->
|
||||
("if " ^ at 1 c ^ " then " ^ inline_text ~lvl:1 a ^ " else " ^ inline_text b, 0)
|
||||
(* A used when is a value, [when c then a]. *)
|
||||
| Form.Sym "when", [ c; a ] -> ("when " ^ at 1 c ^ " then " ^ inline_text a, 0)
|
||||
| Form.Sym "if-let", ({ v = Form.Vec [ _; _ ]; _ } as hd) :: a :: ([] | [ _ ] as b) ->
|
||||
(if_let_head hd ^ " then " ^ inline_text ~lvl:1 a
|
||||
^ (match b with [ b ] -> " else " ^ inline_text b | _ -> ""), 0)
|
||||
| _ -> call ()
|
||||
|
||||
(* [if let P = v], the head (if-let [P v] ...) is written with. *)
|
||||
and if_let_head (hd : Form.t) =
|
||||
match hd.v with
|
||||
| Form.Vec [ pat; v ] -> "if let " ^ at 8 pat ^ " = " ^ at 1 v
|
||||
| _ -> assert false
|
||||
|
||||
(* A one-line slot's text — an arm's value, a then or an else, what follows
|
||||
defer: the statements that fit on a line are written as statements,
|
||||
everything else as a value. [lvl] is what a value in the slot needs. *)
|
||||
@ -595,7 +606,7 @@ let body_guess (h : Form.t) args =
|
||||
let stmt_like (a : Form.t) =
|
||||
match a.v with
|
||||
| Form.List ({ v = Form.Sym h; _ } :: _) ->
|
||||
List.mem h [ "let"; "set"; "when"; "unless"; "cond"; "while";
|
||||
List.mem h [ "let"; "set"; "when"; "if-let"; "unless"; "cond"; "while";
|
||||
"until"; "dotimes"; "match"; "handler-case";
|
||||
"handler-bind"; "restart-case"; "return"; "defer";
|
||||
"do"; "break"; "continue" ]
|
||||
@ -666,7 +677,7 @@ let body_split (h : Form.t) args =
|
||||
| Some k, _ -> Some (k, false)
|
||||
|
||||
let sugar_heads =
|
||||
[ "let"; "set"; "if"; "when"; "cond"; "while"; "until"; "dotimes"; "match";
|
||||
[ "let"; "set"; "if"; "when"; "if-let"; "cond"; "while"; "until"; "dotimes"; "match";
|
||||
"handler-case"; "handler-bind"; "restart-case"; "return"; "defer"; "do";
|
||||
"quasiquote"; "update" ]
|
||||
|
||||
@ -978,6 +989,49 @@ and sugar n (f : Form.t) : string list option =
|
||||
@ [ Source_text.tag b.loc.Loc.line (i ^ "else") ] @ slot (n + 2) b)
|
||||
| Form.List ({ v = Form.Sym "when"; _ } :: c :: (_ :: _ as body)) ->
|
||||
Some ((i ^ "if " ^ at 1 c) :: block (n + 2) body)
|
||||
(* [if let P = v] and its block; an else that is a cond is its elif
|
||||
chain, which is what the reader makes of one. *)
|
||||
| Form.List
|
||||
({ v = Form.Sym "if-let"; _ } :: ({ v = Form.Vec [ _; _ ]; _ } as hd) :: a
|
||||
:: ([] | [ _ ] as b)) ->
|
||||
let simple (x : Form.t) =
|
||||
match x.v with
|
||||
| Form.List ({ v = Form.Sym ("return" | "set" | "break" | "continue"); _ } :: _) -> true
|
||||
| Form.List ({ v = Form.Sym h; _ } :: _) -> not (List.mem h sugar_heads)
|
||||
| _ -> true
|
||||
in
|
||||
let line = i ^ fst (expr f) in
|
||||
if simple a && List.for_all simple b && String.length line <= width
|
||||
&& not (!inside f)
|
||||
then Some [ line ]
|
||||
else
|
||||
let head = (i ^ if_let_head hd) :: slot (n + 2) a in
|
||||
(match b with
|
||||
| [] -> Some head
|
||||
| [ ({ v = Form.List ({ v = Form.Sym "cond"; _ } :: args); _ } as e) ] ->
|
||||
(match pairs args with
|
||||
| Some (_ :: _ as prs) ->
|
||||
let tests, else_ =
|
||||
match List.rev prs with
|
||||
| (k, e) :: rest when is_else k -> (List.rev rest, Some (k, e))
|
||||
| _ -> (prs, None)
|
||||
in
|
||||
Some
|
||||
(head
|
||||
@ List.concat_map
|
||||
(fun ((c : Form.t), b) ->
|
||||
Source_text.tag c.loc.Loc.line (i ^ "elif " ^ at 1 c)
|
||||
:: slot (n + 2) b)
|
||||
tests
|
||||
@ (match else_ with
|
||||
| Some ((k : Form.t), e) ->
|
||||
Source_text.tag k.loc.Loc.line (i ^ "else") :: slot (n + 2) e
|
||||
| None -> []))
|
||||
| _ ->
|
||||
Some (head @ [ Source_text.tag e.loc.Loc.line (i ^ "else") ] @ slot (n + 2) e))
|
||||
| [ e ] ->
|
||||
Some (head @ [ Source_text.tag e.loc.Loc.line (i ^ "else") ] @ slot (n + 2) e)
|
||||
| _ -> None)
|
||||
| Form.List ({ v = Form.Sym "cond"; _ } :: args) ->
|
||||
(match pairs args with
|
||||
| None -> None
|
||||
|
||||
@ -670,6 +670,13 @@ let no_loop loc word =
|
||||
break leaves the loop early, and continue goes on to the next round."
|
||||
word
|
||||
|
||||
(* A [when] has one branch; an else under one is an if's. *)
|
||||
let when_else p =
|
||||
failk "when-else" (peek p).loc
|
||||
"a when has no else — it answers Some of its value when the test holds \
|
||||
and None when it does not. For two branches write if c then a else b, \
|
||||
or an if with an else block"
|
||||
|
||||
let rec expr p : Form.t * int = binary p 1
|
||||
|
||||
and binary p lvl : Form.t * int =
|
||||
@ -774,7 +781,7 @@ and primary p : Form.t * int =
|
||||
| NAME s ->
|
||||
let nxt = peek_at p 1 in
|
||||
let glued_lp = nxt.tok = LP && not nxt.sp in
|
||||
if s = "if" && nxt.sp && starts_value nxt.tok then if_expr p
|
||||
if (s = "if" || s = "when") && nxt.sp && starts_value nxt.tok then if_expr p
|
||||
else if s = "fn" && glued_lp then fn_expr p
|
||||
(* Only the Lisp loop's spellings are refused here, for a message at the
|
||||
word: [loop x = a, ...], [loop([...]):], a bare [loop] over a block
|
||||
@ -849,30 +856,76 @@ and primary p : Form.t * int =
|
||||
failk "expected-value" (where_ p) "expected a value here, and found %s"
|
||||
(show tk)
|
||||
|
||||
(* [if c then a else b]: the one-line form, for a value. *)
|
||||
(* [if c then a else b]: the one-line form, for a value. [if let P = v then
|
||||
a else b] and [when c then a] too. *)
|
||||
and if_expr p =
|
||||
let t = advance p in
|
||||
let c, _ = binary p 1 in
|
||||
let word = match t.tok with NAME w -> w | _ -> "if" in
|
||||
let letp = if word = "if" then if_let_head p else None in
|
||||
let c = match letp with Some m -> m | None -> fst (binary p 1) in
|
||||
(match (peek p).tok with
|
||||
| NAME "then" -> ignore (advance p)
|
||||
| _ ->
|
||||
failk "if-then" (where_ p)
|
||||
"an if inside a line is if c then a else b, and there is no then \
|
||||
after %s. Write the then, or start the if on its own line with its \
|
||||
"an %s inside a line is %s, and there is no then \
|
||||
after %s. Write the then, or start the %s on its own line with its \
|
||||
branches indented under it"
|
||||
(text_of c));
|
||||
word
|
||||
(if word = "when" then "when c then a" else "if c then a else b")
|
||||
(text_of c) word);
|
||||
let a = inline_stmt p in
|
||||
match (peek p).tok with
|
||||
| NAME ("else" | "elif") when word = "when" -> when_else p
|
||||
| NAME "else" ->
|
||||
ignore (advance p);
|
||||
let b = inline_stmt p in
|
||||
(mk p t.loc (Form.List [ sym t.loc "if"; c; a; b ]), 0)
|
||||
(if_let_wrap letp (mk p t.loc (Form.List [ sym t.loc "if"; c; a; b ])), 0)
|
||||
| NAME "elif" ->
|
||||
failk "one-line-elif" (peek p).loc
|
||||
"a one-line if has then and else and no elif. Chain another if after \
|
||||
the else — if a then x else if b then y else z — or write the if over \
|
||||
several lines, where elif goes"
|
||||
| _ -> (mk p t.loc (Form.List [ sym t.loc "when"; c; a ]), 0)
|
||||
| _ -> (if_let_wrap letp (mk p t.loc (Form.List [ sym t.loc "when"; c; a ])), 0)
|
||||
|
||||
(* [if let P = v]: after the [if], the pattern and the value, as the one form
|
||||
[[P v]] that stands where the test would. [None] when no [let] follows. *)
|
||||
and if_let_head p =
|
||||
match (peek p).tok, (peek_at p 1) with
|
||||
| NAME "let", n when n.sp ->
|
||||
let lt = advance p in
|
||||
let pat, _ = unary p in
|
||||
expect_name p "=" ~what:"= and the value the pattern is matched against";
|
||||
let v, _ = binary p 1 in
|
||||
Some (mk p lt.loc (Form.Vec [ pat; v ]))
|
||||
| _ -> None
|
||||
|
||||
(* The if an [if let] head was read into, rewritten to (if-let [P v] then
|
||||
else): [(if [P v] a b)], [(when [P v] body ...)] and an elif chain's
|
||||
[(cond [P v] a c2 b2 ...)], whose rest is the else. *)
|
||||
and if_let_wrap letp (f : Form.t) =
|
||||
match letp with
|
||||
| None -> f
|
||||
| Some m ->
|
||||
let il (h : Form.t) items =
|
||||
{ f with Form.v = Form.List (sym h.Form.loc "if-let" :: m :: items) }
|
||||
in
|
||||
let body (h : Form.t) = function
|
||||
| [ x ] -> x
|
||||
| (x : Form.t) :: _ as xs ->
|
||||
Form.make (Form.List (sym x.Form.loc "do" :: xs)) x.Form.loc
|
||||
| [] -> Form.make (Form.List [ sym h.Form.loc "do" ]) h.Form.loc
|
||||
in
|
||||
match f.Form.v with
|
||||
| Form.List (({ v = Form.Sym "if"; _ } as h) :: c :: rest) when c == m -> il h rest
|
||||
| Form.List (({ v = Form.Sym "when"; _ } as h) :: c :: b) when c == m ->
|
||||
il h [ body h b ]
|
||||
| Form.List (({ v = Form.Sym "cond"; _ } as h) :: c :: b1 :: rest) when c == m ->
|
||||
(match rest with
|
||||
| [] -> il h [ b1 ]
|
||||
| [ { v = Form.Kw "else"; _ }; e ] -> il h [ b1; e ]
|
||||
| (c2 : Form.t) :: _ ->
|
||||
il h [ b1; Form.make (Form.List (sym c2.Form.loc "cond" :: rest)) c2.Form.loc ])
|
||||
| _ -> f
|
||||
|
||||
(* What a one-line slot takes — a match arm's value, a then or an else, the
|
||||
thing after defer: a value, or one of the statements that fit on a line,
|
||||
@ -1227,7 +1280,7 @@ let header_follow p s =
|
||||
| "fn" | "fn-" | "def" | "once" | "const" | "struct" | "union" | "data"
|
||||
| "enum" | "import" ->
|
||||
n.sp && plain_name n.tok
|
||||
| "if" | "while" | "until" | "match" | "let" | "for" ->
|
||||
| "if" | "when" | "while" | "until" | "match" | "let" | "for" ->
|
||||
n.sp && starts_value n.tok
|
||||
&& (match n.tok with
|
||||
| NAME x when x = "=" || List.mem_assoc x assign_ops -> false
|
||||
@ -1414,7 +1467,8 @@ and value_line ?(block_ok = false) (s : st) ~after : Form.t =
|
||||
| NAME (("match" | "handler-case" | "handler-bind" | "restart-case") as w)
|
||||
when header_follow p w ->
|
||||
header s w
|
||||
| NAME "if" when header_follow p "if" && not (then_on_line p) -> header s "if"
|
||||
| NAME (("if" | "when") as w) when header_follow p w && not (then_on_line p) ->
|
||||
header s w
|
||||
| _ ->
|
||||
let e, _ = expr p in
|
||||
match (peek p).tok with
|
||||
@ -1957,12 +2011,16 @@ and header (s : st) w : Form.t =
|
||||
in
|
||||
expect_eol p ~after:(text_of path);
|
||||
form [ alias; path ]
|
||||
| "if" ->
|
||||
let c, _ = binary p 1 in
|
||||
| "if" | "when" ->
|
||||
let letp = if w = "if" then if_let_head p else None in
|
||||
let c = match letp with Some m -> m | None -> fst (binary p 1) in
|
||||
(* The elif and else clauses at the if's column, then the whole form.
|
||||
[oneline] when the if was [if c then a]: its clauses may then be
|
||||
one-line too, [elif c then x] and [else y], or take blocks. *)
|
||||
let clauses ~oneline body =
|
||||
(match (peek p).tok with
|
||||
| NAME ("else" | "elif") when w = "when" && not (assigns p) -> when_else p
|
||||
| _ -> ());
|
||||
let rec elifs acc =
|
||||
match (peek p).tok with
|
||||
| NAME "elif" when not (assigns p) ->
|
||||
@ -2004,7 +2062,7 @@ and header (s : st) w : Form.t =
|
||||
in
|
||||
match els_, else_ with
|
||||
| [], None -> named "when" (c :: body)
|
||||
| [], Some (el, e) -> form [ c; blk s l0 body; blk s el e ]
|
||||
| [], Some (el, e) -> named "if" [ c; blk s l0 body; blk s el e ]
|
||||
| _ ->
|
||||
let pairs =
|
||||
List.concat_map (fun (c, b) -> [ c; blk s c.Form.loc b ]) ((c, body) :: els_)
|
||||
@ -2016,15 +2074,17 @@ and header (s : st) w : Form.t =
|
||||
in
|
||||
named "cond" (pairs @ tail)
|
||||
in
|
||||
if_let_wrap letp @@
|
||||
(match (peek p).tok with
|
||||
| NAME "then" ->
|
||||
ignore (advance p);
|
||||
let a = inline_stmt p in
|
||||
(match (peek p).tok with
|
||||
| NAME ("else" | "elif") when w = "when" -> when_else p
|
||||
| NAME "else" ->
|
||||
ignore (advance p);
|
||||
let b = inline_stmt p in
|
||||
let f = form [ c; a; b ] in
|
||||
let f = named "if" [ c; a; b ] in
|
||||
expect_eol p ~after:(text_of f);
|
||||
f
|
||||
| NAME "elif" ->
|
||||
|
||||
@ -279,6 +279,14 @@ let rec rename_expr owned alias bound (e : Ast.expr) : Ast.expr =
|
||||
in
|
||||
{ a with Ast.body = List.map (rename_expr owned alias bound)
|
||||
a.Ast.body }) arms)
|
||||
| Ast.IfLet (sc, a, e') ->
|
||||
let inner =
|
||||
match a.Ast.pat with Ast.Pctor (_, ns) -> ns @ bound | _ -> bound
|
||||
in
|
||||
Ast.IfLet (go sc,
|
||||
{ a with Ast.body = List.map (rename_expr owned alias inner)
|
||||
a.Ast.body },
|
||||
Option.map go e')
|
||||
(* A quoted symbol naming something the package declares.
|
||||
[(Form.Sym {.s "Cursor"})] is what a quasiquote desugars to, and it is
|
||||
the one place a package's name survives into a *string* — which is
|
||||
@ -840,6 +848,7 @@ let rec expr_uses acc (e : Ast.expr) =
|
||||
| Ast.Call (h, args) -> go h; gos args
|
||||
| Ast.Match (sc, arms) ->
|
||||
go sc; List.iter (fun (a : Ast.arm) -> gos a.Ast.body) arms
|
||||
| Ast.IfLet (sc, a, e') -> go sc; gos a.Ast.body; Option.iter go e'
|
||||
| Ast.Struct (n, kvs) ->
|
||||
acc := (n, e.Ast.loc) :: !acc;
|
||||
List.iter (fun (_, v) -> go v) kvs
|
||||
|
||||
12
lib/parse.ml
12
lib/parse.ml
@ -489,6 +489,18 @@ and form f mk (head : Form.t) (args : Form.t list) : Ast.expr =
|
||||
|
||||
| Sym "cond" -> cond f args
|
||||
|
||||
(* (if-let [pattern value] then) and (if-let [pattern value] then else):
|
||||
[value] is matched against [pattern], whose names are bound in [then]
|
||||
only. Any [match] pattern may stand there. *)
|
||||
| Sym "if-let" ->
|
||||
(match args with
|
||||
| { v = Vec [ p; v ]; _ } :: t :: rest when List.length rest <= 1 ->
|
||||
let arm = { Ast.pat = pattern p; body = [ expr t ]; aloc = p.loc } in
|
||||
mk (Ast.IfLet (expr v, arm, Option.map expr (List.nth_opt rest 0)))
|
||||
| _ ->
|
||||
fail f "if-let is (if-let [pattern value] then) or \
|
||||
(if-let [pattern value] then else)")
|
||||
|
||||
(* Short-circuiting, so they cannot be ordinary calls. *)
|
||||
| Sym "and" -> shortcircuit f args ~is_and:true
|
||||
| Sym "or" -> shortcircuit f args ~is_and:false
|
||||
|
||||
@ -4157,6 +4157,22 @@ flan_dyn flan_dyn_get(flan_dyn m, flan_dyn k, const uint8_t *loc,
|
||||
return flan_dyn_map_get(m, k);
|
||||
}
|
||||
|
||||
/* The [get] builtin's, which [.field] does not share: over a map it is
|
||||
* [flan_dyn_get], and over a vec or a text it is [at] that answers nil for an
|
||||
* index out of range, negative included, where [at] traps. The index must
|
||||
* still be an int — a wrong kind of key is a mistake, not an absence. */
|
||||
flan_dyn flan_dyn_get_at(flan_dyn v, flan_dyn i, const uint8_t *loc,
|
||||
int64_t loclen) {
|
||||
int64_t k, len;
|
||||
flan_obj *o;
|
||||
if (!is_text(v) && !is_vec(v)) return flan_dyn_get(v, i, loc, loclen);
|
||||
k = need_index(loc, loclen, "get", v, i);
|
||||
o = dyn_obj(v);
|
||||
len = o->kind == OBJ_VIEW ? view_len(loc, loclen, "get", o) : o->len;
|
||||
if (k < 0 || k >= len) return flan_dyn_nil();
|
||||
return flan_dyn_at(v, i, loc, loclen);
|
||||
}
|
||||
|
||||
static flan_dyn contains_walk(flan_dyn m, flan_dyn k) {
|
||||
flan_obj *o = want_map(walk_loc, walk_len, walk_op, m, k);
|
||||
if (o->kind == OBJ_VIEW) {
|
||||
|
||||
@ -245,6 +245,10 @@ flan_dyn flan_dyn_map_get(flan_dyn m, flan_dyn k);
|
||||
/* [get]'s, and a dyn's [.field]: [flan_dyn_map_get] with a site. */
|
||||
flan_dyn flan_dyn_get(flan_dyn m, flan_dyn k, const uint8_t *loc,
|
||||
int64_t loclen);
|
||||
/* The [get] builtin's: [flan_dyn_get] over a map, and over a vec or a text
|
||||
* the element, or nil for an index out of range. */
|
||||
flan_dyn flan_dyn_get_at(flan_dyn v, flan_dyn i, const uint8_t *loc,
|
||||
int64_t loclen);
|
||||
void flan_dyn_map_set(flan_dyn m, flan_dyn k, flan_dyn v);
|
||||
/* [put]'s: [flan_dyn_map_set], with the site a typed class slot's refusal
|
||||
* prints. */
|
||||
|
||||
@ -214,6 +214,16 @@ Each item: the proposal, then the reason in one line.
|
||||
line after a one-line `if c then a`, at its column, continues it (section
|
||||
3, item 6); each such clause is one-line (`elif c then x`, `else y`) or
|
||||
takes a block.
|
||||
- **`when c`** plus a block, or `when c then a`, reads as `when`, which is
|
||||
what an `if` without `else` reads as too. No `else` or `elif` follows it.
|
||||
A `when` whose value is kept (a `let`'s value, an argument, a return) gives
|
||||
`Some(a)` when `c` holds and `None` when it does not; where a `dyn` is
|
||||
wanted, `a` or `nil`. As a statement it gives nothing. **Built.**
|
||||
- **`if let P = v`** plus a block reads as `(if-let [P v] then)`; `elif` and
|
||||
`else` follow as for `if`, the rest of the chain being the `if-let`'s else.
|
||||
`P` is any `match` pattern, and its names are bound in the block only. One
|
||||
line: `if let Some(g) = o then g else 0`. A pattern that cannot fail, a
|
||||
plain name or `_`, is refused toward `let`. **Built.**
|
||||
- **`while c`, `until c`**, optional label first: `while :outer c`. **Built.**
|
||||
- **`for i in range(n)`**, `range(a, b)`, `range(a, b, step)` read as
|
||||
`dotimes`. `range` here is syntax, not a function. `..` is avoided because
|
||||
|
||||
63
test/programs/get-checked.flan
Normal file
63
test/programs/get-checked.flan
Normal file
@ -0,0 +1,63 @@
|
||||
;;;; get over an array, a slice, a string and a Vec is at that answers None
|
||||
;;;; for an index out of range, negative included, one index per dimension.
|
||||
;;;; Over a dyn it answers nil, and more keys walk a level each.
|
||||
|
||||
(defn show [o (Option i32)] ()
|
||||
(match o (Some v) (println v) None (println "none")))
|
||||
|
||||
(defn three [] (Vec i32)
|
||||
(let [v (vec-new i32)] (push v 10) (push v 20) (push v 30) v))
|
||||
|
||||
(defn dvec [] dyn [10 [20 21] 30])
|
||||
(defn dmap [] dyn {:a 1 :b [5 6]})
|
||||
|
||||
(defn main [] ()
|
||||
(let [a [1 2 3]
|
||||
grid [[1 2 3] [4 5 6]]
|
||||
s (slice a)
|
||||
v (three)
|
||||
n (length a)
|
||||
vv (vec-new (Vec i32) context/temp)]
|
||||
(push vv v)
|
||||
;; -1, 0, len-1 and len on an array.
|
||||
(show (get a -1))
|
||||
(show (get a 0))
|
||||
(show (get a (- n 1)))
|
||||
(show (get a n))
|
||||
;; Two dimensions, each tested.
|
||||
(let [r 0 c 1]
|
||||
(show (get grid (+ r 1) (- c 1)))
|
||||
(show (get grid (- r 1) c))
|
||||
(show (get grid r (+ c 2))))
|
||||
(show (get grid 1 2))
|
||||
(show (get grid 2 0))
|
||||
;; A slice.
|
||||
(show (get s 2))
|
||||
(show (get s 3))
|
||||
;; A Vec, and one a call answered.
|
||||
(show (get v -1))
|
||||
(show (get v 0))
|
||||
(show (get v 2))
|
||||
(show (get v 3))
|
||||
(show (get (three) 1))
|
||||
;; A Vec of Vecs: the inner length is tested only once the outer index is.
|
||||
(show (get vv 0 2))
|
||||
(show (get vv 0 3))
|
||||
(show (get vv 1 0))
|
||||
;; A string's byte.
|
||||
(match (get "hey" 1) (Some b) (println b) None (println "none"))
|
||||
(match (get "hey" 3) (Some b) (println b) None (println "none")))
|
||||
;; Dyn.
|
||||
(let [d (dvec) m (dmap)]
|
||||
(println (get d -1))
|
||||
(println (get d 0))
|
||||
(println (get d 2))
|
||||
(println (get d 3))
|
||||
(println (get d 1 1))
|
||||
(println (get d 1 2))
|
||||
(println (get d 5 0))
|
||||
(println (get m :a))
|
||||
(println (get m :z))
|
||||
(println (get m :b 1))
|
||||
(println (get m :z 1))
|
||||
(println (.a m))))
|
||||
56
test/programs/if-let.fln
Normal file
56
test/programs/if-let.fln
Normal file
@ -0,0 +1,56 @@
|
||||
;; if let: the block runs when the pattern matches, its names bound there only.
|
||||
|
||||
data Shape
|
||||
Rect(w: i32, h: i32)
|
||||
Dot
|
||||
|
||||
enum Dir
|
||||
north = 0
|
||||
south = 1
|
||||
|
||||
fn describe(o: Option(i32), k: i32) -> i32
|
||||
if let Some(g) = o
|
||||
g + 1
|
||||
elif k > 5
|
||||
100
|
||||
else
|
||||
0
|
||||
|
||||
fn first(xs: [3 i32]) -> i32
|
||||
if let Some(x) = get(xs, 0) then x else -1
|
||||
|
||||
;; Nested: a pattern tested inside the block of another.
|
||||
fn area(s: Option(Shape)) -> i32
|
||||
if let Some(x) = s
|
||||
if let Rect(w, h) = x
|
||||
w * h
|
||||
else
|
||||
-1
|
||||
else
|
||||
-2
|
||||
|
||||
fn main()
|
||||
let g = 7
|
||||
println(describe(Some(4), 0))
|
||||
println(describe(None, 9))
|
||||
println(describe(None, 1))
|
||||
println(first([9, 8, 7]))
|
||||
;; Shadowing: g is the payload inside the block and the outer g after it.
|
||||
if let Some(g) = Some(1)
|
||||
println(g)
|
||||
println(g)
|
||||
;; Any match pattern.
|
||||
if let None = get([1, 2], 5)
|
||||
println("absent")
|
||||
if let :north = Dir.north
|
||||
println("north")
|
||||
println(area(Some(Shape.Rect{.w 2 .h 3})))
|
||||
println(area(Some(Shape.Dot)))
|
||||
println(area(None))
|
||||
;; when on one line and with a block.
|
||||
let w = when g > 3 then g * 2
|
||||
match w
|
||||
Some(v) -> println(v)
|
||||
None -> println("none")
|
||||
when g > 1
|
||||
println("when block")
|
||||
42
test/programs/when-value.flan
Normal file
42
test/programs/when-value.flan
Normal file
@ -0,0 +1,42 @@
|
||||
;;;; A when whose value is kept answers an Option: Some of its body when the
|
||||
;;;; test holds, None when it does not. As a statement it answers nothing.
|
||||
;;;; Where a dyn is wanted it answers the body or nil, since dyn has no
|
||||
;;;; Option. A body that is already an Option is not flattened.
|
||||
|
||||
(defn show [o (Option i32)] ()
|
||||
(match o (Some v) (println v) None (println "none")))
|
||||
|
||||
;; Returned: the return type is the want.
|
||||
(defn half [n i32] (Option i32) (when (= 0 (% n 2)) (/ n 2)))
|
||||
|
||||
;; Nested, as Rust's bool::then: None from the body stays apart from a
|
||||
;; failed test.
|
||||
(defn wrap [c bool o (Option i32)] (Option (Option i32)) (when c o))
|
||||
|
||||
(defn level [oo (Option (Option i32))] ()
|
||||
(match oo
|
||||
(Some o) (match o (Some v) (println v) None (println "some none"))
|
||||
None (println "none")))
|
||||
|
||||
;; Dyn: the body or nil.
|
||||
(defn dyn-when [x] dyn (when x 5))
|
||||
|
||||
(defn main [] ()
|
||||
(show (half 10))
|
||||
(show (half 7))
|
||||
;; A let's value.
|
||||
(let [a (when (> 3 2) 42)
|
||||
b (when (> 2 3) 42)]
|
||||
(show a)
|
||||
(show b))
|
||||
;; An argument.
|
||||
(show (when true 9))
|
||||
(level (wrap true (Some 1)))
|
||||
(level (wrap true None))
|
||||
(level (wrap false (Some 1)))
|
||||
(println (dyn-when true))
|
||||
(println (dyn-when nil))
|
||||
;; Statements, unchanged.
|
||||
(when true (println "ran"))
|
||||
(when false (println "not run"))
|
||||
(println "end"))
|
||||
@ -2058,6 +2058,29 @@ let () =
|
||||
dyn_if_truthy_out;
|
||||
outputs ~x86:true "dyn if truthiness, --x86" "programs/dyn-if-truthy.flan"
|
||||
dyn_if_truthy_out;
|
||||
(* A kept when is an Option; get is a checked lookup; if let. *)
|
||||
let when_value_out =
|
||||
"5\nnone\n42\nnone\n9\n1\nsome none\nnone\n5\nnil\nran\nend\n"
|
||||
in
|
||||
outputs "when as a value" "programs/when-value.flan" when_value_out;
|
||||
outputs ~opt:"-O0" "when as a value, -O0" "programs/when-value.flan" when_value_out;
|
||||
outputs ~x86:true "when as a value, --x86" "programs/when-value.flan" when_value_out;
|
||||
let get_checked_out =
|
||||
"none\n1\n3\nnone\n4\nnone\nnone\n6\nnone\n3\nnone\n\
|
||||
none\n10\n30\nnone\n20\n30\nnone\nnone\n101\nnone\n\
|
||||
nil\n10\n30\nnil\n21\nnil\nnil\n1\nnil\n6\nnil\n1\n"
|
||||
in
|
||||
outputs "get as a checked lookup" "programs/get-checked.flan" get_checked_out;
|
||||
outputs ~opt:"-O0" "get as a checked lookup, -O0" "programs/get-checked.flan"
|
||||
get_checked_out;
|
||||
outputs ~x86:true "get as a checked lookup, --x86" "programs/get-checked.flan"
|
||||
get_checked_out;
|
||||
let if_let_out =
|
||||
"5\n100\n0\n9\n1\n7\nabsent\nnorth\n6\n-1\n-2\n14\nwhen block\n"
|
||||
in
|
||||
outputs "if let" "programs/if-let.fln" if_let_out;
|
||||
outputs ~opt:"-O0" "if let, -O0" "programs/if-let.fln" if_let_out;
|
||||
outputs ~x86:true "if let, --x86" "programs/if-let.fln" if_let_out;
|
||||
(* format-f64, the first number formatter a caller can steer. The three
|
||||
lines that would ship wrong are pinned deliberately: 0.999995 at five
|
||||
places, where the rounded fraction equals the scale and is the next
|
||||
|
||||
@ -8125,5 +8125,23 @@ let () =
|
||||
parse_rejects "_ in a defgeneric's return slot"
|
||||
~needle:"defgeneric's methods each have their own"
|
||||
"(defgeneric area [s] _)";
|
||||
(* if-let refuses a pattern that cannot fail, toward let; the program half
|
||||
is programs/if-let.flan. *)
|
||||
rejects_check "if-let over a plain name"
|
||||
~needle:"the pattern g is a plain name, which always matches"
|
||||
"(defn main [] () (if-let [g (Some 1)] (println g)))";
|
||||
rejects_check "and says let" ~needle:"(let [g ...] ...)"
|
||||
"(defn main [] () (if-let [g (Some 1)] (println g)))";
|
||||
rejects_check "if-let over _" ~needle:"the pattern _ always matches"
|
||||
"(defn main [] () (if-let [_ (Some 1)] (println 1)))";
|
||||
accepts "if-let over a case with no fields"
|
||||
"(defdata S [(A []) (B [])])\n(defn main [] () (if-let [A S.B] (println 1)))";
|
||||
(* A used when is an Option, and a statement's is nothing. *)
|
||||
accepts "a let's when is an Option"
|
||||
"(defn main [] () (let [x (the (Option i32) (when true 1))] (println x)))";
|
||||
rejects_check "a when is not its branch's type" ~needle:"(Option i32)"
|
||||
"(defn f [] i32 (when true 1))\n(defn main [] ())";
|
||||
rejects_check "a map's get takes one key" ~needle:"a map's get takes one key"
|
||||
"(defn main [] () (let [m (map-new i32 i32)] (println (get m 1 2))))";
|
||||
|
||||
Test_support.report ()
|
||||
|
||||
@ -933,6 +933,26 @@ let () =
|
||||
" sort-by(xs, fn(a, b) =>\n g(a)\n a < b)";
|
||||
round "one closer for a call in a call"
|
||||
"(defn f [] () (println (run (fn [] (g) 1))))" " println(run(fn() =>\n g()\n 1))";
|
||||
(* if let and when, read both ways and printed back. *)
|
||||
round "if let with a block and an else"
|
||||
"(defn f [o (Option i32)] i32 (if-let [(Some g) o] (do (println g) g) 0))"
|
||||
" if let Some(g) = o\n println(g)\n g\n else\n 0";
|
||||
round "if let on one line"
|
||||
"(defn f [o (Option i32)] i32 (if-let [(Some g) o] g 0))"
|
||||
" if let Some(g) = o then g else 0";
|
||||
round "if let with elif"
|
||||
"(defn f [o (Option i32) k i32] i32 (if-let [(Some g) o] (+ g 1) (cond (> k 5) 100 :else 0)))"
|
||||
" elif k > 5\n 100\n else\n 0";
|
||||
round "if let with no else" "(defn f [o (Option i32)] () (if-let [(Some g) o] (do (println g) (println g))))"
|
||||
" if let Some(g) = o\n println(g)";
|
||||
round "a kept when" "(defn f [] () (let [w (when (> a 1) 2)] (g w)))"
|
||||
" let w = when a > 1 then 2";
|
||||
reads "when with a block" "when a\n b()\n c()" "(when a (b) (c))";
|
||||
reads "when on one line" "when a then b()" "(when a (b))";
|
||||
reads "if let with elif and no else" "if let None = o\n a()\nelif c\n b()"
|
||||
"(if-let [None o] (a) (cond c (b)))";
|
||||
refuses "when has no else" "when a then b() else c()" "indent/when-else" "a when has no else";
|
||||
refuses "nor an else block" "when a\n b()\nelse\n c()" "indent/when-else" "a when has no else";
|
||||
round "a typed block lambda in a call"
|
||||
"(defn f [] () (h (the (Fn [C] bool) (fn [c] (g c) (> (.n c) 3)))))"
|
||||
" h(fn(c: C) -> bool =>\n g(c)\n c.n > 3)";
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user