gapt.proofs.context.update.SkolemFunction.scala Maven / Gradle / Ivy

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General Architecture for Proof Theory

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package gapt.proofs.context.update

import gapt.expr.Abs
import gapt.expr.Const
import gapt.expr.Expr
import gapt.expr.formula.Quant
import gapt.expr.ty.FunctionType
import gapt.expr.util.freeVariables
import gapt.logic.hol.SkolemFunctions
import gapt.proofs.context.Context
import gapt.proofs.context.facet.Constants
import gapt.proofs.context.facet.skolemFunsFacet
import gapt.proofs.context.State

case class SkolemFunction(sym: Const, defn: Expr) extends Update {
  val Abs.Block(argumentVariables, strongQuantifier @ Quant(boundVariable, matrix, isForall)) = defn: @unchecked
  require(sym.ty == FunctionType(boundVariable.ty, argumentVariables.map(_.ty)))
  require(freeVariables(defn).isEmpty)

  override def apply(ctx: Context): State = {
    ctx.check(sym.ty)
    ctx.check(defn)
    ctx.state.update[Constants](_ + sym)
      .update[SkolemFunctions](_.+(sym, defn))
  }
}