Joseph Ferano
a4c6b996ff
The trio the author decided on 2026-09-20 is now all built: def is CL's defparameter — its initialiser runs on every daemon re-run, unguarded, so an edited initialiser repaints the same storage on C-c C-c plus re-run — defonce (Clojure's name for CL's defvar, per the author) initialises once behind the .init~once. flag, and defconst stays the image. One parse arm reads both forms; the difference is Ast.reinit, carried to Tast.global's grerun. Emit.startup_plan gives a def no guard flag, and Check.check_global lifts every def initialiser — zero and literal included — into global/<n>, so the host's startup reaches it through the function cell and a re-evaluated def swaps it (Session's def_inits; Emit.redefinition declares the cell for a non-sibling target). The old defvar spelling is refused with the rename and both compiling spellings, and every program, test, doc and editor list is swept — except sand.flan, the author's live WIP, whose seven defvar lines are flagged in FIX.org and keep its three dependent tests red on this branch.
90 lines
3.5 KiB
Plaintext
90 lines
3.5 KiB
Plaintext
;;;; Computed global initialisers — plan.org, Data model.
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;;;;
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;;;; A global whose value is not something a linker can write into the image.
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;;;; The initialiser is lifted into a function of its own and called at startup,
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;;;; from main, after the runtime is up and before a line of the program's own
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;;;; code — Odin's __$startup_runtime shape rather than a constructor. Both
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;;;; backends do it the same way, which is what the x86 survey is comparing.
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;;;;
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;;;; What each half of this file is asserting:
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;;;;
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;;;; - an arena allocated at startup and used from main, which is the form
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;;;; the author kept writing: (defonce frame Allocator (arena-new N)).
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;;;; - the order. `derived` is written above the global it reads, so the
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;;;; declaration order is the wrong one and the sort is what makes it 30.
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;;;; - a dependency that runs through a call rather than through the text of
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;;;; the initialiser: `via-fn` names no global at all, and the function it
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;;;; calls reads one.
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;;;; - control flow in an initialiser. Every one of these needs a frame, and
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;;;; before the lift there was none — a `let` in an initialiser indexed a
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;;;; slot array of length zero and took the compiler down with it.
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;;;; - a container loaded by its own initialiser, and a data type case
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;;;; written into a global. Both were refused while there was nowhere for
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;;;; an initialiser to run.
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(defdata Shape [Nothing (Circle [r i32]) (Square [side i32])])
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;; Written above `base`, and it reads it.
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(defonce derived i64 (* base 10))
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(defonce base i64 (+ 1 2))
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(defn twice-base [] i64 (* base 2))
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;; Names no global; the function it calls does.
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(defonce via-fn i64 (+ (twice-base) 1))
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;; The author's arena, and the Vec it is meant to hold.
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(defonce frame Allocator (arena-new 262144))
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;; Control flow, each shape in its own global.
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(defn maybe [] (Option i32) (Some 3))
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(defonce matched i32 (match (maybe) (Some x) x None 0))
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(defonce branched i64 (if (> base 2) (let [k (+ base 1)] (* k 2)) 0))
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(defonce counted i64 (let [t (i64 0)] (while (< t 4) (set t (+ t 1))) t))
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;; A data type case: a store at startup, where a constant would have needed a
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;; byte-level encoder for the payload blob.
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(defonce shape Shape (Shape.Circle {.r 7}))
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;; And a container whose real value only exists behind an allocator.
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(defonce names (Vec i64) (vec-new i64))
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;; [def], the re-run form, in a plain run — where there is no re-run, so each
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;; is simply its initialiser's value. What these four pin is that every
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;; spelling lowers and starts identically on both backends, with the
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;; initialiser lifted into [global/<n>] whatever it is (a def's always is,
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;; zero and literal included) rather than written into the image.
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(def d-zero [2 u32])
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(def d-typed i64 (+ base 2))
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(def d-const i64 5)
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(def d-dyn 6)
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(defn main [] i32
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(println derived)
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(println base)
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(println via-fn)
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(println matched)
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(println branched)
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(println counted)
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(match shape
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(Circle r) (println r)
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(Square s) (println s)
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Nothing (println -1))
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;; The Vec was made with the default allocator at startup and is still the
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;; program's when main runs.
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(push names 11)
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(push names 22)
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(println (len (as-slice names)))
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(println (at names 1))
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(free names)
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;; And the arena, used the way sand.flan means to use it.
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(with-allocator frame
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(let [v (vec-new i64)]
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(push v 7)
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(println (at v 0))))
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(free-all frame)
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(println (i32 (at d-zero 0)))
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(println d-typed)
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(println d-const)
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(println d-dyn)
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0)
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