lean4-htt/src/Lean/Compiler/Util.lean
2022-08-07 22:05:19 -07:00

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/-
Copyright (c) 2019 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
import Lean.Compiler.CompilerM
import Lean.Meta.Match.MatcherInfo
namespace Lean.Compiler
/--
Return `true` if `mdata` should be preserved.
Right now, we don't preserve any `MData`, but this may
change in the future when we add support for debugging information
-/
def isCompilerRelevantMData (_mdata : MData) : Bool :=
false
/--
Return `true` if `e` is a `lcProof` application.
Recall that we use `lcProof` to erase all nested proofs.
-/
def isLCProof (e : Expr) : Bool :=
e.isAppOfArity ``lcProof 1
/--
Return `true` if `e` is a `lcUnreachable` application.
-/
def isLcUnreachable (e : Expr) : Bool :=
e.isAppOfArity ``lcUnreachable 1
/--
Return `true` if `e` is a `lcCast` application.
-/
def isLcCast? (e : Expr) : Option Expr :=
if e.isAppOfArity ``lcCast 3 then
some e.appArg!
else
none
/-- Create `lcProof p` -/
def mkLcProof (p : Expr) :=
mkApp (mkConst ``lcProof []) p
/-- Create `lcUnreachable type` -/
def mkLcUnreachable (type : Expr) : CompilerM Expr := do
liftMetaM do
let u ← Meta.getLevel type
return .app (.const ``lcUnreachable [u]) type
/-- Create `lcCast expectedType e : expectedType` -/
def mkLcCast (e : Expr) (expectedType : Expr) : CompilerM Expr := do
liftMetaM do
let type ← Meta.inferType e
let u ← Meta.getLevel type
let v ← Meta.getLevel expectedType
return mkApp3 (.const ``lcCast [u, v]) type expectedType e
/--
Store information about `matcher` and `casesOn` declarations.
We treat them uniformly in the code generator.
-/
structure CasesInfo where
arity : Nat
discrsRange : Std.Range
altsRange : Std.Range
altNumParams : Array Nat
motivePos : Nat
private def getCasesOnInductiveVal? (declName : Name) : CoreM (Option InductiveVal) := do
unless isCasesOnRecursor (← getEnv) declName do return none
let .inductInfo val ← getConstInfo declName.getPrefix | return none
return some val
private def getCasesOnInfo? (declName : Name) : CoreM (Option CasesInfo) := do
let some val ← getCasesOnInductiveVal? declName | return none
let motivePos := val.numParams
let arity := val.numIndices + val.numParams + 1 /- motive -/ + 1 /- major -/ + val.numCtors
let majorPos := val.numIndices + val.numParams + 1 /- motive -/
let discrsRange := { start := majorPos, stop := majorPos + 1 }
let altsRange := { start := majorPos + 1, stop := arity }
let altNumParams ← val.ctors.toArray.mapM fun ctor => do
let .ctorInfo ctorVal ← getConstInfo ctor | unreachable!
return ctorVal.numFields
return some { motivePos, arity, discrsRange, altsRange, altNumParams }
def getCasesInfo? (declName : Name) : CoreM (Option CasesInfo) := do
if let some matcherInfo ← Meta.getMatcherInfo? declName then
return some {
motivePos := matcherInfo.getMotivePos
arity := matcherInfo.arity
discrsRange := matcherInfo.getDiscrRange
altsRange := matcherInfo.getAltRange
altNumParams := matcherInfo.altNumParams
}
else
getCasesOnInfo? declName
def isCasesApp? (e : Expr) : CoreM (Option CasesInfo) := do
let .const declName _ := e.getAppFn | return none
if let some info ← getCasesInfo? declName then
assert! info.arity == e.getAppNumArgs
return some info
else
return none
def updateMotive (casesInfo : CasesInfo) (args : Array Expr) (newResultingType : Expr) : MetaM (Array Expr) := do
-- TODO: make it more robust, it is assuming the motive is eta-expanded
args.modifyM casesInfo.motivePos fun motive => do
Meta.lambdaTelescope motive fun xs _ => Meta.mkLambdaFVars xs newResultingType
def getCtorArity? (declName : Name) : CoreM (Option Nat) := do
let .ctorInfo val ← getConstInfo declName | return none
return val.numParams + val.numFields
/--
List of types that have builtin runtime support
-/
def builtinRuntimeTypes : List Name := [
``String,
``UInt8, ``UInt16, ``UInt32, ``UInt64, ``USize,
``Float,
``Thunk, ``Task,
``Array, ``ByteArray, ``FloatArray,
``Nat, ``Int
]
/--
Return `true` iff `declName` is the name of a type with builtin support in the runtime.
-/
def isRuntimeBultinType (declName : Name) : Bool :=
builtinRuntimeTypes.contains declName
end Lean.Compiler