Lean migration: Phase 5 (language, CFGs, traces, Program)

- Spa.Language.Base: Expr/BasicStmt/Stmt + HasVar relations; StringSet
  lifts to Finset String
- Spa.Language.Semantics: Value/Env/Env.Mem, big-step relations,
  LatticeInterpretation (respects-≈ field drops out with =)
- Spa.Language.Graphs: Graph with nodes : Fin size → List BasicStmt
  (Vec lookup lemmas lift to Fin.append_left/right), comp/link/loop/
  skipto/singleton/wrap/buildCfg, predecessors via List.finRange
- Spa.Language.Traces: Trace + EndToEndTrace (Prop-valued)
- Spa.Language.Properties: trace embeddings, loop lemmas,
  buildCfg_sufficient; the 80-line Fin-disjointness block reduces to
  castAdd_ne_natAdd + mathlib list lemmas
- Spa.Language: Program (vars via Finset.sort — toList is noncomputable)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
2026-06-09 19:30:42 -07:00
parent 781d7947e0
commit 2cfd0a2fb7
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/-
Port of `Language/Properties.agda`.
Correspondence:
-≢ (and the whole "ugly" Fin-disjointness block:
idx→f∉↑ʳᵉ, idx→f∉pair, idx→f∉cart, help, helpAll)
↦ Fin.castAdd_ne_natAdd + not_mem_edges_castAdd_link
(mathlib `List.mem_append`/`mem_map`/`mem_product`
replace the hand-rolled membership eliminations)
wrap-preds-∅ ↦ wrap_predecessors_eq_nil
wrap-input, wrap-output ↦ Graph.wrapInput/wrapOutput + wrap_inputs/wrap_outputs
Trace-∙ˡ/ʳ ↦ Trace.comp_left / Trace.comp_right
Trace-↦ˡ/ʳ ↦ Trace.link_left / Trace.link_right
Trace-loop ↦ Trace.loop
EndToEndTrace-∙ˡ/ʳ ↦ EndToEndTrace.comp_left / .comp_right
loop-edge-groups,
loop-edge-help ↦ (inlined: the four edge groups are reached through
`List.mem_append` directly)
EndToEndTrace-loop ↦ EndToEndTrace.loop
EndToEndTrace-loop² ↦ EndToEndTrace.loop_concat
EndToEndTrace-loop⁰ ↦ EndToEndTrace.loop_empty
_++_ ↦ EndToEndTrace.concat
EndToEndTrace-singleton ↦ EndToEndTrace.singleton (+ .singleton_nil)
EndToEndTrace-wrap ↦ EndToEndTrace.wrap
buildCfg-sufficient ↦ buildCfg_sufficient
-/
import Spa.Language.Traces
namespace Spa
open Graph
/-- Agda: `↑-≢`. -/
theorem Fin.castAdd_ne_natAdd {n m : } (i : Fin n) (j : Fin m) :
Fin.castAdd m i Fin.natAdd n j := by
intro h
have := congrArg Fin.val h
simp only [Fin.coe_castAdd, Fin.coe_natAdd] at this
omega
/-! ### Trace embeddings -/
section Embeddings
variable {g₁ g₂ : Graph} {ρ₁ ρ₂ : Env}
/-- Agda: `Trace-∙ˡ`. -/
theorem Trace.comp_left {idx₁ idx₂ : g₁.Index}
(tr : Trace g₁ idx₁ idx₂ ρ₁ ρ₂) :
Trace (g₁ g₂) (idx₁.castAdd g₂.size) (idx₂.castAdd g₂.size) ρ₁ ρ₂ := by
induction tr with
| single hbs =>
exact Trace.single (by rwa [show (g₁ g₂).nodes = Fin.append g₁.nodes g₂.nodes from rfl,
Fin.append_left])
| edge hbs he _ ih =>
refine Trace.edge ?_ ?_ ih
· rwa [show (g₁ g₂).nodes = Fin.append g₁.nodes g₂.nodes from rfl, Fin.append_left]
· exact List.mem_append_left _ (List.mem_map_of_mem _ he)
/-- Agda: `Trace-∙ʳ`. -/
theorem Trace.comp_right {idx₁ idx₂ : g₂.Index}
(tr : Trace g₂ idx₁ idx₂ ρ₁ ρ₂) :
Trace (g₁ g₂) (idx₁.natAdd g₁.size) (idx₂.natAdd g₁.size) ρ₁ ρ₂ := by
induction tr with
| single hbs =>
exact Trace.single (by rwa [show (g₁ g₂).nodes = Fin.append g₁.nodes g₂.nodes from rfl,
Fin.append_right])
| edge hbs he _ ih =>
refine Trace.edge ?_ ?_ ih
· rwa [show (g₁ g₂).nodes = Fin.append g₁.nodes g₂.nodes from rfl, Fin.append_right]
· exact List.mem_append_right _ (List.mem_map_of_mem _ he)
/-- Agda: `Trace-↦ˡ`. -/
theorem Trace.link_left {idx₁ idx₂ : g₁.Index}
(tr : Trace g₁ idx₁ idx₂ ρ₁ ρ₂) :
Trace (g₁ g₂) (idx₁.castAdd g₂.size) (idx₂.castAdd g₂.size) ρ₁ ρ₂ := by
induction tr with
| single hbs =>
exact Trace.single (by rwa [show (g₁ g₂).nodes = Fin.append g₁.nodes g₂.nodes from rfl,
Fin.append_left])
| edge hbs he _ ih =>
refine Trace.edge ?_ ?_ ih
· rwa [show (g₁ g₂).nodes = Fin.append g₁.nodes g₂.nodes from rfl, Fin.append_left]
· exact List.mem_append_left _ (List.mem_append_left _ (List.mem_map_of_mem _ he))
/-- Agda: `Trace-↦ʳ`. -/
theorem Trace.link_right {idx₁ idx₂ : g₂.Index}
(tr : Trace g₂ idx₁ idx₂ ρ₁ ρ₂) :
Trace (g₁ g₂) (idx₁.natAdd g₁.size) (idx₂.natAdd g₁.size) ρ₁ ρ₂ := by
induction tr with
| single hbs =>
exact Trace.single (by rwa [show (g₁ g₂).nodes = Fin.append g₁.nodes g₂.nodes from rfl,
Fin.append_right])
| edge hbs he _ ih =>
refine Trace.edge ?_ ?_ ih
· rwa [show (g₁ g₂).nodes = Fin.append g₁.nodes g₂.nodes from rfl, Fin.append_right]
· exact List.mem_append_left _
(List.mem_append_right _ (List.mem_map_of_mem _ he))
/-- Agda: `EndToEndTrace-∙ˡ`. -/
theorem EndToEndTrace.comp_left (etr : EndToEndTrace g₁ ρ₁ ρ₂) :
EndToEndTrace (g₁ g₂) ρ₁ ρ₂ := by
obtain i₁, h₁, i₂, h₂, tr := etr
exact i₁.castAdd g₂.size, List.mem_append_left _ (List.mem_map_of_mem _ h₁),
i₂.castAdd g₂.size, List.mem_append_left _ (List.mem_map_of_mem _ h₂),
tr.comp_left
/-- Agda: `EndToEndTrace-∙ʳ`. -/
theorem EndToEndTrace.comp_right (etr : EndToEndTrace g₂ ρ₁ ρ₂) :
EndToEndTrace (g₁ g₂) ρ₁ ρ₂ := by
obtain i₁, h₁, i₂, h₂, tr := etr
exact i₁.natAdd g₁.size, List.mem_append_right _ (List.mem_map_of_mem _ h₁),
i₂.natAdd g₁.size, List.mem_append_right _ (List.mem_map_of_mem _ h₂),
tr.comp_right
/-- Agda: `_++_` — sequencing end-to-end traces over `⤳`. -/
theorem EndToEndTrace.concat {ρ₃ : Env} (etr₁ : EndToEndTrace g₁ ρ₁ ρ₂)
(etr₂ : EndToEndTrace g₂ ρ₂ ρ₃) : EndToEndTrace (g₁ g₂) ρ₁ ρ₃ := by
obtain i₁, h₁, i₂, h₂, tr₁ := etr₁
obtain j₁, k₁, j₂, k₂, tr₂ := etr₂
refine i₁.castAdd g₂.size, List.mem_map_of_mem _ h₁,
j₂.natAdd g₁.size, List.mem_map_of_mem _ k₂,
Trace.concat tr₁.link_left ?_ tr₂.link_right
exact List.mem_append_right _
(List.mem_product.mpr List.mem_map_of_mem _ h₂, List.mem_map_of_mem _ k₁)
end Embeddings
/-! ### Loops -/
section Loop
variable {g : Graph} {ρ₁ ρ₂ ρ₃ : Env}
/-- Agda: `Trace-loop`. -/
theorem Trace.loop {idx₁ idx₂ : g.Index} (tr : Trace g idx₁ idx₂ ρ₁ ρ₂) :
Trace (Graph.loop g) (idx₁.natAdd 2) (idx₂.natAdd 2) ρ₁ ρ₂ := by
induction tr with
| single hbs =>
exact Trace.single (by
rwa [show (Graph.loop g).nodes = Fin.append (fun _ : Fin 2 => []) g.nodes from rfl,
Fin.append_right])
| edge hbs he _ ih =>
refine Trace.edge ?_ ?_ ih
· rwa [show (Graph.loop g).nodes = Fin.append (fun _ : Fin 2 => []) g.nodes from rfl,
Fin.append_right]
· exact List.mem_append_left _ (List.mem_append_left _
(List.mem_append_left _ (List.mem_map_of_mem _ he)))
private theorem loop_nodes_at_in :
(Graph.loop g).nodes g.loopIn = [] :=
Fin.append_left (fun _ : Fin 2 => []) g.nodes 0
private theorem loop_nodes_at_out :
(Graph.loop g).nodes g.loopOut = [] :=
Fin.append_left (fun _ : Fin 2 => []) g.nodes 1
/-- Agda: `EndToEndTrace-loop`. -/
theorem EndToEndTrace.loop (etr : EndToEndTrace g ρ₁ ρ₂) :
EndToEndTrace (Graph.loop g) ρ₁ ρ₂ := by
obtain i₁, h₁, i₂, h₂, tr := etr
-- the edge in → (2 ↑ʳ i₁), reached through the second edge group
have hin : (g.loopIn, i₁.natAdd 2) (Graph.loop g).edges := by
refine List.mem_append_left _ (List.mem_append_left _ (List.mem_append_right _ ?_))
exact List.mem_map_of_mem _ (List.mem_map_of_mem _ h₁)
-- the edge (2 ↑ʳ i₂) → out, reached through the third edge group
have hout : (i₂.natAdd 2, g.loopOut) (Graph.loop g).edges := by
refine List.mem_append_left _ (List.mem_append_right _ ?_)
exact List.mem_map_of_mem _ (List.mem_map_of_mem _ h₂)
refine g.loopIn, List.mem_singleton_self _, g.loopOut, List.mem_singleton_self _, ?_
exact Trace.concat (Trace.single (loop_nodes_at_in EvalBasicStmts.nil)) hin
(Trace.concat tr.loop hout (Trace.single (loop_nodes_at_out EvalBasicStmts.nil)))
private theorem loop_edge_out_in :
((g.loopOut, g.loopIn) : (Graph.loop g).Edge) (Graph.loop g).edges := by
refine List.mem_append_right _ ?_
exact List.mem_cons_self _ _
/-- Agda: `EndToEndTrace-loop²`. -/
theorem EndToEndTrace.loop_concat (etr₁ : EndToEndTrace (Graph.loop g) ρ₁ ρ₂)
(etr₂ : EndToEndTrace (Graph.loop g) ρ₂ ρ₃) :
EndToEndTrace (Graph.loop g) ρ₁ ρ₃ := by
obtain i₁, h₁, i₂, h₂, tr₁ := etr₁
obtain j₁, k₁, j₂, k₂, tr₂ := etr₂
simp only [Graph.loop_inputs, Graph.loop_outputs, List.mem_singleton] at h₁ h₂ k₁ k₂
subst h₁; subst h₂; subst k₁; subst k₂
exact g.loopIn, List.mem_singleton_self _, g.loopOut, List.mem_singleton_self _,
Trace.concat tr₁ loop_edge_out_in tr₂
/-- Agda: `EndToEndTrace-loop⁰`. -/
theorem EndToEndTrace.loop_empty {ρ : Env} : EndToEndTrace (Graph.loop g) ρ ρ := by
have hedge : ((g.loopIn, g.loopOut) : (Graph.loop g).Edge) (Graph.loop g).edges :=
List.mem_append_right _ (List.mem_cons_of_mem _ (List.mem_cons_self _ _))
exact g.loopIn, List.mem_singleton_self _, g.loopOut, List.mem_singleton_self _,
Trace.concat (Trace.single (loop_nodes_at_in EvalBasicStmts.nil)) hedge
(Trace.single (loop_nodes_at_out EvalBasicStmts.nil))
end Loop
/-! ### Singletons, wrap, and the main result -/
/-- Agda: `EndToEndTrace-singleton`. -/
theorem EndToEndTrace.singleton {bss : List BasicStmt} {ρ₁ ρ₂ : Env}
(h : EvalBasicStmts ρ₁ bss ρ₂) : EndToEndTrace (Graph.singleton bss) ρ₁ ρ₂ :=
(0 : Fin 1), List.mem_singleton_self _, (0 : Fin 1), List.mem_singleton_self _,
Trace.single h
/-- Agda: `EndToEndTrace-singleton[]`. -/
theorem EndToEndTrace.singleton_nil (ρ : Env) :
EndToEndTrace (Graph.singleton []) ρ ρ :=
EndToEndTrace.singleton EvalBasicStmts.nil
/-- Agda: `EndToEndTrace-wrap`. -/
theorem EndToEndTrace.wrap {g : Graph} {ρ₁ ρ₂ : Env}
(etr : EndToEndTrace g ρ₁ ρ₂) : EndToEndTrace (Graph.wrap g) ρ₁ ρ₂ :=
(EndToEndTrace.singleton_nil ρ₁).concat (etr.concat (EndToEndTrace.singleton_nil ρ₂))
/-- Agda: `buildCfg-sufficient` — every terminating execution is witnessed by
an end-to-end trace through the control-flow graph. -/
theorem buildCfg_sufficient {s : Stmt} {ρ₁ ρ₂ : Env}
(h : EvalStmt ρ₁ s ρ₂) : EndToEndTrace (buildCfg s) ρ₁ ρ₂ := by
induction h with
| basic ρ₁ ρ₂ bs hbs =>
exact EndToEndTrace.singleton (EvalBasicStmts.cons hbs EvalBasicStmts.nil)
| andThen ρ₁ ρ₂ ρ₃ s₁ s₂ _ _ ih₁ ih₂ =>
exact ih₁.concat ih₂
| ifTrue ρ₁ ρ₂ e z s₁ s₂ _ _ _ ih =>
exact ih.comp_left
| ifFalse ρ₁ ρ₂ e s₁ s₂ _ _ ih =>
exact ih.comp_right
| whileTrue ρ₁ ρ₂ ρ₃ e z s _ _ _ _ ih₁ ih₂ =>
exact (ih₁.loop).loop_concat ih₂
| whileFalse ρ e s _ =>
exact EndToEndTrace.loop_empty
/-! ### The wrapped graph's entry has no predecessors (Agda's "ugly" block) -/
/-- The input of `wrap g` (Agda: `wrap-input`). -/
def Graph.wrapInput (g : Graph) : (Graph.wrap g).Index :=
(0 : Fin 1).castAdd ((g Graph.singleton []).size)
/-- The output of `wrap g` (Agda: `wrap-output`). -/
def Graph.wrapOutput (g : Graph) : (Graph.wrap g).Index :=
Fin.natAdd 1 ((Fin.natAdd g.size (0 : Fin 1)))
theorem Graph.wrap_inputs (g : Graph) :
(Graph.wrap g).inputs = [g.wrapInput] := rfl
theorem Graph.wrap_outputs (g : Graph) :
(Graph.wrap g).outputs = [g.wrapOutput] := rfl
/-- Agda: `help`/`helpAll` — no edge of `singleton [] ⤳ g₂` ends at a
`castAdd`-injected node (all edge targets are `natAdd`s). -/
private theorem not_mem_edges_castAdd_link {g₂ : Graph} (i : Fin 1)
(idx : (Graph.singleton [] g₂).Index) :
((idx, i.castAdd g₂.size) : (Graph.singleton [] g₂).Edge)
(Graph.singleton [] g₂).edges := by
intro h
rcases List.mem_append.mp h with h' | h'
· rcases List.mem_append.mp h' with h'' | h''
· -- lifted edges of `singleton []`: there are none
simp [Graph.singleton, Graph.liftEdgeL] at h''
· -- lifted edges of g₂: targets are natAdd
obtain e, _, heq := List.mem_map.mp h''
exact Fin.castAdd_ne_natAdd i e.2 (congrArg Prod.snd heq).symm
· -- product edges: targets are natAdd'd inputs of g₂
obtain -, hb := List.mem_product.mp h'
obtain j, -, heq := List.mem_map.mp hb
exact Fin.castAdd_ne_natAdd i j heq.symm
/-- Agda: `wrap-preds-∅` — the entry node of a wrapped graph has no
incoming edges. -/
theorem Graph.wrap_predecessors_eq_nil (g : Graph) (idx : (Graph.wrap g).Index)
(h : idx (Graph.wrap g).inputs) :
(Graph.wrap g).predecessors idx = [] := by
rw [Graph.wrap_inputs, List.mem_singleton] at h
subst h
rw [Graph.predecessors, List.filter_eq_nil_iff]
intro idx' _
simpa using not_mem_edges_castAdd_link (g₂ := g Graph.singleton []) 0 idx'
end Spa