lean4-htt/src/Init/MetaTypes.lean
Kim Morrison 69340297be chore: add simp configuration to norm_cast syntax
chore: define NormCastConfig earlier
2024-12-03 17:59:23 +11:00

274 lines
9.2 KiB
Text

/-
Copyright (c) Leonardo de Moura. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
prelude
import Init.Core
namespace Lean
structure NameGenerator where
namePrefix : Name := `_uniq
idx : Nat := 1
deriving Inhabited
/-- Syntax objects for a Lean module. -/
structure Module where
header : Syntax
commands : Array Syntax
namespace Meta
inductive TransparencyMode where
/-- unfold all constants, even those tagged as `@[irreducible]`. -/
| all
/-- unfold all constants except those tagged as `@[irreducible]`. -/
| default
/-- unfold only constants tagged with the `@[reducible]` attribute. -/
| reducible
/-- unfold reducible constants and constants tagged with the `@[instance]` attribute. -/
| instances
deriving Inhabited, BEq
inductive EtaStructMode where
/-- Enable eta for structure and classes. -/
| all
/-- Enable eta only for structures that are not classes. -/
| notClasses
/-- Disable eta for structures and classes. -/
| none
deriving Inhabited, BEq
namespace DSimp
/--
The configuration for `dsimp`.
Passed to `dsimp` using, for example, the `dsimp (config := {zeta := false})` syntax.
Implementation note: this structure is only used for processing the `(config := ...)` syntax, and it is not used internally.
It is immediately converted to `Lean.Meta.Simp.Config` by `Lean.Elab.Tactic.elabSimpConfig`.
-/
structure Config where
/--
When `true` (default: `true`), performs zeta reduction of let expressions.
That is, `let x := v; e[x]` reduces to `e[v]`.
See also `zetaDelta`.
-/
zeta : Bool := true
/--
When `true` (default: `true`), performs beta reduction of applications of `fun` expressions.
That is, `(fun x => e[x]) v` reduces to `e[v]`.
-/
beta : Bool := true
/--
TODO (currently unimplemented). When `true` (default: `true`), performs eta reduction for `fun` expressions.
That is, `(fun x => f x)` reduces to `f`.
-/
eta : Bool := true
/--
Configures how to determine definitional equality between two structure instances.
See documentation for `Lean.Meta.EtaStructMode`.
-/
etaStruct : EtaStructMode := .all
/--
When `true` (default: `true`), reduces `match` expressions applied to constructors.
-/
iota : Bool := true
/--
When `true` (default: `true`), reduces projections of structure constructors.
-/
proj : Bool := true
/--
When `true` (default: `false`), rewrites a proposition `p` to `True` or `False` by inferring
a `Decidable p` instance and reducing it.
-/
decide : Bool := false
/--
When `true` (default: `false`), unfolds definitions.
This can be enabled using the `simp!` syntax.
-/
autoUnfold : Bool := false
/--
If `failIfUnchanged` is `true` (default: `true`), then calls to `simp`, `dsimp`, or `simp_all`
will fail if they do not make progress.
-/
failIfUnchanged : Bool := true
/--
If `unfoldPartialApp` is `true` (default: `false`), then calls to `simp`, `dsimp`, or `simp_all`
will unfold even partial applications of `f` when we request `f` to be unfolded.
-/
unfoldPartialApp : Bool := false
/--
When `true` (default: `false`), local definitions are unfolded.
That is, given a local context containing entry `x : t := e`, the free variable `x` reduces to `e`.
-/
zetaDelta : Bool := false
/--
When `index` (default : `true`) is `false`, `simp` will only use the root symbol
to find candidate `simp` theorems. It approximates Lean 3 `simp` behavior.
-/
index : Bool := true
deriving Inhabited, BEq
end DSimp
namespace Simp
def defaultMaxSteps := 100000
/--
The configuration for `simp`.
Passed to `simp` using, for example, the `simp (config := {contextual := true})` syntax.
See also `Lean.Meta.Simp.neutralConfig` and `Lean.Meta.DSimp.Config`.
-/
structure Config where
/--
The maximum number of subexpressions to visit when performing simplification.
The default is 100000.
-/
maxSteps : Nat := defaultMaxSteps
/--
When simp discharges side conditions for conditional lemmas, it can recursively apply simplification.
The `maxDischargeDepth` (default: 2) is the maximum recursion depth when recursively applying simplification to side conditions.
-/
maxDischargeDepth : Nat := 2
/--
When `contextual` is true (default: `false`) and simplification encounters an implication `p → q`
it includes `p` as an additional simp lemma when simplifying `q`.
-/
contextual : Bool := false
/--
When true (default: `true`) then the simplifier caches the result of simplifying each subexpression, if possible.
-/
memoize : Bool := true
/--
When `singlePass` is `true` (default: `false`), the simplifier runs through a single round of simplification,
which consists of running pre-methods, recursing using congruence lemmas, and then running post-methods.
Otherwise, when it is `false`, it iteratively applies this simplification procedure.
-/
singlePass : Bool := false
/--
When `true` (default: `true`), performs zeta reduction of let expressions.
That is, `let x := v; e[x]` reduces to `e[v]`.
See also `zetaDelta`.
-/
zeta : Bool := true
/--
When `true` (default: `true`), performs beta reduction of applications of `fun` expressions.
That is, `(fun x => e[x]) v` reduces to `e[v]`.
-/
beta : Bool := true
/--
TODO (currently unimplemented). When `true` (default: `true`), performs eta reduction for `fun` expressions.
That is, `(fun x => f x)` reduces to `f`.
-/
eta : Bool := true
/--
Configures how to determine definitional equality between two structure instances.
See documentation for `Lean.Meta.EtaStructMode`.
-/
etaStruct : EtaStructMode := .all
/--
When `true` (default: `true`), reduces `match` expressions applied to constructors.
-/
iota : Bool := true
/--
When `true` (default: `true`), reduces projections of structure constructors.
-/
proj : Bool := true
/--
When `true` (default: `false`), rewrites a proposition `p` to `True` or `False` by inferring
a `Decidable p` instance and reducing it.
-/
decide : Bool := false
/-- When `true` (default: `false`), simplifies simple arithmetic expressions. -/
arith : Bool := false
/--
When `true` (default: `false`), unfolds definitions.
This can be enabled using the `simp!` syntax.
-/
autoUnfold : Bool := false
/--
When `true` (default: `true`) then switches to `dsimp` on dependent arguments
if there is no congruence theorem that would allow `simp` to visit them.
When `dsimp` is `false`, then the argument is not visited.
-/
dsimp : Bool := true
/--
If `failIfUnchanged` is `true` (default: `true`), then calls to `simp`, `dsimp`, or `simp_all`
will fail if they do not make progress.
-/
failIfUnchanged : Bool := true
/--
If `ground` is `true` (default: `false`), then ground terms are reduced.
A term is ground when it does not contain free or meta variables.
Reduction is interrupted at a function application `f ...` if `f` is marked to not be unfolded.
Ground term reduction applies `@[seval]` lemmas.
-/
ground : Bool := false
/--
If `unfoldPartialApp` is `true` (default: `false`), then calls to `simp`, `dsimp`, or `simp_all`
will unfold even partial applications of `f` when we request `f` to be unfolded.
-/
unfoldPartialApp : Bool := false
/--
When `true` (default: `false`), local definitions are unfolded.
That is, given a local context containing entry `x : t := e`, the free variable `x` reduces to `e`.
-/
zetaDelta : Bool := false
/--
When `index` (default : `true`) is `false`, `simp` will only use the root symbol
to find candidate `simp` theorems. It approximates Lean 3 `simp` behavior.
-/
index : Bool := true
/--
If `implicitDefEqProofs := true`, `simp` does not create proof terms when the
input and output terms are definitionally equal.
-/
implicitDefEqProofs : Bool := true
deriving Inhabited, BEq
-- Configuration object for `simp_all`
structure ConfigCtx extends Config where
contextual := true
/--
A neutral configuration for `simp`, turning off all reductions and other built-in simplifications.
-/
def neutralConfig : Simp.Config := {
zeta := false
beta := false
eta := false
iota := false
proj := false
decide := false
arith := false
autoUnfold := false
ground := false
zetaDelta := false
}
structure NormCastConfig extends Simp.Config where
zeta := false
beta := false
eta := false
proj := false
iota := false
end Simp
/-- Configuration for which occurrences that match an expression should be rewritten. -/
inductive Occurrences where
/-- All occurrences should be rewritten. -/
| all
/-- A list of indices for which occurrences should be rewritten. -/
| pos (idxs : List Nat)
/-- A list of indices for which occurrences should not be rewritten. -/
| neg (idxs : List Nat)
deriving Inhabited, BEq
instance : Coe (List Nat) Occurrences := ⟨.pos⟩
end Lean.Meta