cdbe29b46d
An important part of the interface of a function is the parameter names, for making used of named arguments. This PR makes the parameter names print in a reliable way. The parameters of the type now appear as hygienic names if they cannot be used as named arguments. Modifies the heuristic for how parameters are chosen to appear before or after the colon. The rule is now that parameters start appearing after the colon at the first non-dependent non-instance-implicit parameter that has a name unusable as a named argument. This is a refinement of #2846. Fixes the issue where consecutive hygienic names pretty print without a space separating them, so we now have `(x✝ y✝ : Nat)` rather than `(x✝y✝ : Nat)`. Breaking change: `Lean.PrettyPrinter.Formatter.pushToken` now takes an additional boolean `ident` argument, which should be `true` for identifiers. Used to insert discretionary space between consecutive identifiers. Closes #5810
84 lines
2.5 KiB
Text
84 lines
2.5 KiB
Text
/-!
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# `delabConstWithSignature` avoids using inaccessible names
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-/
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/-!
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Defined without named arguments, prints without named arguments.
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-/
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/-- info: String.append : String → String → String -/
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#guard_msgs in #check String.append
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/-!
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The List argument is not named, it is not printed as a named argument.
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-/
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/-- info: List.length.{u_1} {α : Type u_1} : List α → Nat -/
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#guard_msgs in #check List.length
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/-!
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All arguments are named, all are printed as named arguments.
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-/
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/-- info: Nat.pos_pow_of_pos {n : Nat} (m : Nat) (h : 0 < n) : 0 < n ^ m -/
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#guard_msgs in #check Nat.pos_pow_of_pos
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/-!
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The hypothesis is not a named argument, so it's not printed as a named argument.
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-/
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def Nat.pos_pow_of_pos' {n : Nat} (m : Nat) : 0 < n → 0 < n ^ m := Nat.pos_pow_of_pos m
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/-- info: Nat.pos_pow_of_pos' {n : Nat} (m : Nat) : 0 < n → 0 < n ^ m -/
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#guard_msgs in #check Nat.pos_pow_of_pos'
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/-!
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Repetition of a named argument, only the first is printed as a named argument.
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The second is made hygienic.
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-/
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def foo (n n : Nat) : Fin (n + 1) := 0
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/-- info: foo (n n✝ : Nat) : Fin (n✝ + 1) -/
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#guard_msgs in #check foo
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/-!
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Same, but a named argument still follows, and its name is preserved.
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-/
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def foo' (n n : Nat) (a : Fin ((by clear n; exact n) + 1)) : Fin (n + 1) := 0
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/-- info: foo' (n n✝ : Nat) (a : Fin (n + 1)) : Fin (n✝ + 1) -/
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#guard_msgs in #check foo'
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/-!
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Named argument after non-dependent inaccessible name, still stays after the colon.
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Prints with named pi notation.
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-/
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def foo'' : String → (needle : String) → String := fun _ yo => yo
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/-- info: foo'' : String → (needle : String) → String -/
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#guard_msgs in #check foo''
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/-!
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Named argument after inaccessible name that's still a dependent argument.
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Stays before the colon, and the names are grouped.
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-/
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def foo''' : (_ : Nat) → (n : Nat) → Fin (n + by clear n; assumption) := sorry
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/-- info: foo''' (x✝ n : Nat) : Fin (n + x✝) -/
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#guard_msgs in #check foo'''
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/-!
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Named argument after inaccessible name, still stays after the colon.
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Here, because it's a dependent type the named pi notation shows the name.
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-/
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def bar : String → (n : Nat) → Fin (n+1) := fun _ n => ⟨0, Nat.zero_lt_succ n⟩
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/-- info: bar : String → (n : Nat) → Fin (n + 1) -/
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#guard_msgs in #check bar
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/-!
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Instance argument is an inaccessible name, and we assume that it is a nameless instance,
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so it goes before the colon.
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-/
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def bar' [LT α] (x : α) : x < x := sorry
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/-- info: bar'.{u_1} {α : Type u_1} [LT α] (x : α) : x < x -/
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#guard_msgs in #check bar'
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