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.
66 lines
2.5 KiB
Plaintext
66 lines
2.5 KiB
Plaintext
;;;; A stopped stack holding two pointers into Vec storage, one of which is
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;;;; already dead. The allocation registry is what lets the inspector tell
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;;;; them apart, and this is the program that shows it:
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;;;;
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;;;; ("live" "(Ptr Enemy)" "<ptr (Enemy {.hp 41 .x 2})>")
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;;;; ("dead" "(Ptr Enemy)" "<ptr dead: was Enemy, freed at step N>")
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;;;;
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;;;; N is the registry's own event counter and is no part of the claim: it
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;;;; moves if anything allocates or frees ahead of this program's two Vecs.
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;;;; `test_dev.ml' matches around it and never on it.
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;;;;
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;;;; Both lines are what `(:op "locals" :frame 1)` answers with, and the
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;;;; `a pointer the registry knows about' case in test_dev.ml is what drives
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;;;; them. They were read off a running session by hand once; they are not
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;;;; read by hand any more.
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;;;;
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;;;; Why a Vec rather than a struct on the stack: a stack address is not in
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;;;; the registry by design — the shadow stack already answers for a local by
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;;;; name — so a pointer to one renders <ptr>, which is neither half of what
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;;;; this is demonstrating.
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(import agent "vendor:agent")
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(defstruct Boom [why i32])
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(defstruct Enemy [hp i32 x i32])
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;;; The address root — `(:op "at" :addr N)' — takes a number, and the things
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;;; that hand out addresses as numbers all live outside the language: a
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;;; debugger, valgrind, a C shim's printf. A Flan program has no cast for it
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;;; on purpose — pointer arithmetic out of an integer is what the type system
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;;; stops describing — so saying one out loud is a declare-c.
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(declare-c ptr-num [p (Ptr Enemy)] i64 "flan_dev_reg_number")
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;;; Where the two addresses are left for a reader to find. Globals rather than
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;;; a printed line because a global is reachable by name from `C-x C-e' while
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;;; the program is stopped, and a local is not: the test asks the session for
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;;; them the way a person at the break loop would.
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(defonce live-addr i64)
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(defonce dead-addr i64)
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(defn deeper [] i64
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(restart-case
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(do (error (Boom {.why 7})) 1)
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(carry-on [] 5)))
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(defn outer [] i64
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(let [v (vec-new Enemy)
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w (vec-new Enemy)]
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(push v (Enemy {.hp 41 .x 2}))
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(push w (Enemy {.hp 7 .x 9}))
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(let [live (addr (at v 0))
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dead (addr (at w 0))]
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(free w)
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(set live-addr (ptr-num live))
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(set dead-addr (ptr-num dead))
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(deeper))))
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(defonce ticks i64)
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(defn main [] i32
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(agent/start "/tmp/flan-dev-ptr-fallback.sock")
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(print (outer)) (println "")
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(dotimes [i 4000]
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(agent/wait 5)
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(set ticks (+ ticks 1)))
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0)
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