06fb4bec52
This PR wraps the top-level command parser with `withPosition` to enforce indentation in `by` blocks, combined with an empty-by fallback for better error messages. This subsumes #3215 (which introduced `withPosition commandParser` but without the empty-by fallback). It is also related to #9524, which explores elaboration with empty tactic sequences — this PR reuses that idea for the empty-by fallback, so that a `by` not followed by an indented tactic produces an elaboration error (unsolved goals) rather than a parse error. **Changes:** - `topLevelCommandParserFn` now uses `(withPosition commandParser).fn`, setting the saved position at the start of each top-level command - `tacticSeqIndentGt` gains an empty tactic sequence fallback (`pushNone`) so that missing indentation produces an elaboration error (unsolved goals) instead of a parse error - `isEmptyBy` in `goalsAt?` removed: with strict `by` indentation, empty `by` blocks parse successfully via `pushNone` (producing empty nodes) rather than producing `.missing` syntax, making the `isEmptyBy` check dead code. The `isEmpty` helper in `isSyntheticTacticCompletion` continues to work correctly because it handles both `.missing` and empty nodes from `pushNone` (via the vacuously-true `args.all isEmpty` on `#[]`) - Test files updated to indent `by` blocks and expression continuations that were previously at column 0 **Behavior:** - Top-level `by` blocks now require indentation (column > 0 for commands at column 0) - Commands indented inside `section` require proofs to be indented past the command's column - `#guard_msgs in example : True := by` works because tactic indentation is checked against the outermost command's column - Expression continuations (not just `by`) must also be indented past the command, which is slightly more strict but more consistent - `have : True := by` followed by a dedent now correctly puts `this` in scope in the outer tactic block (the `have` is structurally complete with an unsolved-goal error, rather than a parse error) **Code changes observed in practice (lean4 test suite + Mathlib):** - `by` blocks: top-level `theorem ... := by` / `decreasing_by` followed by tactics at column 0 must be indented - `variable` continuations: `variable {A : Type*} [Foo A]\n{B : Type*}` where the second line starts at column 0 must be indented (most common category in Mathlib) - Expression continuations: `def f : T :=\nexpr` or `#synth Foo\n[args]` where the body/arguments start at column 0 - Structure literals: `.symm\n{ toFun := ...` where the struct literal starts at column 0 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
58 lines
1.4 KiB
Text
58 lines
1.4 KiB
Text
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def f (x : Nat) (y : Bool) :=
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x + if y then 1 else 0
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def g (x y : Nat) :=
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x + y
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#check f ?x ?x -- error the first occurrence (?x : Nat) and the second (?x : Bool)
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#check g ?x ?x -- ok
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def h1 (x : Nat) : Nat := by
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refine g ?hole ?hole; -- it is the same hole
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case hole => exact x
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#eval h1 10
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theorem ex1 : h1 10 = 20 :=
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rfl
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def h2 (x : Nat) : Nat := by
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refine g ?hole ?hole;
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exact x+x
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theorem ex2 : h2 10 = 40 :=
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rfl
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def foo (f : Nat → Nat) (x : Nat) := f x
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def bla (x : Nat) (f : Nat → Nat) := f x
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def boo (f : Nat → Nat) (g : Bool → Nat) := f (g true)
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#check foo (fun x => ?hole) ?hole
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#check bla ?hole (fun x => ?hole)
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#check boo (fun x => ?hole) (fun y => ?hole) -- error the local contexts of the two holes are incompatible
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def h3 (x : Nat) : Nat := by
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apply boo;
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case f => refine fun y => ?hole + 1; exact x; -- `fun y => ?hole + 1` and assigned `?hole := x`
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case g => refine fun b => ?hole -- `fun b => ?hole` it works because assignment is compatible
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#eval h3 10
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theorem ex3 : h3 10 = 11 := rfl
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def h4 (x : Nat) : Nat := by
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refine foo (fun y => ?hole + 2) ?hole;
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-- note that the local context of ?hole has be shrunk by the second occurrence
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exact x
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#eval h4 10
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theorem ex4 : h4 10 = 12 := rfl
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def h5 (x : Nat) : Nat := by
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apply boo;
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case f => intro y; refine ?hole + 1; exact y; -- `fun y => ?hole + 1` and assigned `?hole := y`
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case g => refine fun b => ?hole -- error
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