diff --git a/DESCRIPTION b/DESCRIPTION
index 84630662..d9697736 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -60,6 +60,7 @@ Roxygen: list(markdown = TRUE, r6 = TRUE)
 RoxygenNote: 7.1.2
 Collate:
     'Condition.R'
+    'ContextPV.R'
     'Design.R'
     'NoDefault.R'
     'Param.R'
diff --git a/NAMESPACE b/NAMESPACE
index 6153cbcd..7df28f76 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -2,6 +2,7 @@
 
 S3method(as.data.table,Param)
 S3method(as.data.table,ParamSet)
+S3method(print,ContextPV)
 S3method(print,Domain)
 S3method(print,FullTuneToken)
 S3method(print,ObjectTuneToken)
@@ -10,6 +11,7 @@ S3method(rd_info,ParamSet)
 export(CondAnyOf)
 export(CondEqual)
 export(Condition)
+export(ContextPV)
 export(Design)
 export(NO_DEF)
 export(NoDefault)
diff --git a/R/ContextPV.R b/R/ContextPV.R
new file mode 100644
index 00000000..bf4cf953
--- /dev/null
+++ b/R/ContextPV.R
@@ -0,0 +1,45 @@
+
+#' @title ParamSet Value that Depends on Context
+#'
+#' @description
+#' Set a [`ParamSet`]`$value` slot to this. The `.fn` function will
+#' be called with the respective function arguments. The function argument
+#' names of `.fn` must be a subset of the [`ParamSet`]'s `$context_available` slot.
+#'
+#' @param .fn `function`\cr
+#'   Function to be executed in the context where [`ParamSet`] values
+#'   are retrieved.
+#' @param ... any\cr
+#'   Variable names to make available to function. Functions are run in
+#'   the [`.GlobalEnv`][base::.GlobalEnv] scope and only the variables
+#'   named in `...` will be available.
+#' @examples
+#' p = ps(x = p_dbl(), y = p_dbl())
+#' p$context_available = c("a", "x")
+#'
+#' b = 10
+#'
+#' p$values$x = ContextPV(function(a) a * b, b)
+#' p$values$y = ContextPV(function(x) x^2)
+#' # ContextPV uses the value of b right at this moment
+#' b = 20
+#'
+#' p$values$x(1)  # 1 * 10
+#'
+#' p$get_values(context = list(a = 10, x = 20))  # using 'a' from context: 10 * 10
+#'
+#' @export
+ContextPV = function(.fn, ...) {
+  assert_function(.fn)
+  set_class(crate(.fn, ...), c("ContextPV", "function"))
+}
+
+#' @export
+print.ContextPV = function(x, ...) {
+  y = x
+  cat("ContextPV ")
+  environment(y) = .GlobalEnv
+  print(unclass(y), ...)
+  cat("Using following environment:\n")
+  print(as.list(environment(x)))
+}
diff --git a/R/Param.R b/R/Param.R
index a004c4d2..648a9600 100644
--- a/R/Param.R
+++ b/R/Param.R
@@ -77,6 +77,7 @@ Param = R6Class("Param",
           TRUE
         }, error = function(e) paste("tune token invalid:", conditionMessage(e))))
       }
+      if (inherits(x, "ContextPV")) return(TRUE)
       ch = private$.check(x)
       ifelse(isTRUE(ch) || has_element(self$special_vals, x), TRUE, ch)
     },
diff --git a/R/ParamSet.R b/R/ParamSet.R
index 103efceb..526569cb 100644
--- a/R/ParamSet.R
+++ b/R/ParamSet.R
@@ -45,6 +45,13 @@ ParamSet = R6Class("ParamSet",
     #' Default is `TRUE`, only switch this off if you know what you are doing.
     assert_values = TRUE,
 
+    #' @field context_available (`character`)\cr
+    #' Context that [`ContextPV`] values can rely on being present. When assigning a [`ContextPV`]
+    #' to a `$values` element, its argument names must be a subset of `$context_available`.
+    #' Conversely, the `context` argument of `$get_values()` must contain named elements
+    #' corresponding to all `$context_available` entries.
+    context_available = character(0),
+
     #' @description
     #' Creates a new instance of this [R6][R6::R6Class] class.
     #'
@@ -138,15 +145,20 @@ ParamSet = R6Class("ParamSet",
     #' Return values `with_token`, `without_token` or `only_token`?
     #' @param check_required (`logical(1)`)\cr
     #' Check if all required parameters are set?
+    #' @param context (`environment` | named `list`)\cr
+    #'   Must have elements named by `$context_available`, which are then given to the
+    #'   respective arguments of [`ContextPV`] values.
     #' @return Named `list()`.
     get_values = function(class = NULL, is_bounded = NULL, tags = NULL,
-      type = "with_token", check_required = TRUE) {
+      type = "with_token", check_required = TRUE, context = parent.frame()) {
       assert_choice(type, c("with_token", "without_token", "only_token"))
       assert_flag(check_required)
       values = self$values
       params = self$params_unid
       ns = names(values)
 
+      if (type != "only_token") assert_names(names(context), type = "unique", must.include = self$context_available)
+
       if (type == "without_token") {
         values = discard(values, is, "TuneToken")
       } else if (type == "only_token") {
@@ -160,7 +172,23 @@ ParamSet = R6Class("ParamSet",
         }
       }
 
-      values[intersect(names(values), self$ids(class = class, is_bounded = is_bounded, tags = tags))]
+      values = values[intersect(names(values), self$ids(class = class, is_bounded = is_bounded, tags = tags))]
+
+      if (type == "only_token") return(values)
+
+      imap(values, function(x, name) {
+        if (!inherits(x, "ContextPV")) return(x)
+        x = do.call(x, lapply(names(formals(args(x))), get, pos = context))
+        checked = params[[name]]$check(x)
+        if (!isTRUE(checked)) {
+          stopf("ContextPV for %s resulted in infeasible value:\n%s",
+            name, checked)
+        }
+        if (!has_element(params[[name]]$special_vals, x)) {
+          x = params[[name]]$convert(x)
+        }
+        x
+      })
     },
 
     #' @description
@@ -225,11 +253,18 @@ ParamSet = R6Class("ParamSet",
         return(sprintf("Parameter '%s' not available.%s", ns[extra], did_you_mean(extra, ids)))
       }
 
-      # check each parameters feasibility
-      for (n in ns) {
-        ch = params[[n]]$check(xs[[n]])
-        if (test_string(ch)) { # we failed a check, return string
-          return(paste0(n, ": ", ch))
+      # check each parameters feasibility, only necessary if we are a leaf ParamSet
+      if (!inherits(self, "ParamSetCollection")) {
+        for (n in ns) {
+          if (inherits(xs[[n]], "ContextPV")) {
+            ch = check_names(names(formals(args(xs[[n]]))), type = "unique", subset.of = self$context_available)
+            if (!isTRUE(ch)) ch = sprintf("Argument names of ContextPV %s", ch)
+          } else {
+            ch = params[[n]]$check(xs[[n]])
+          }
+          if (test_string(ch)) { # we failed a check, return string
+            return(paste0(n, ": ", ch))
+          }
         }
       }
 
@@ -247,7 +282,9 @@ ParamSet = R6Class("ParamSet",
           # - if param is there, then parent must be there, then cond must be true
           # - if param is not there
           cond = deps$cond[[j]]
-          ok = (p1id %in% ns && p2id %in% ns && cond$test(xs[[p2id]])) ||
+          ok = (p1id %in% ns && p2id %in% ns &&
+                !inherits(xs[[p2id]], "ContextPV") &&
+                cond$test(xs[[p2id]])) ||
             (p1id %nin% ns)
           if (isFALSE(ok)) {
             message = sprintf("The parameter '%s' can only be set if the following condition is met '%s'.",
@@ -256,6 +293,8 @@ ParamSet = R6Class("ParamSet",
             if (is.null(val)) {
               message = sprintf(paste("%s Instead the parameter value for '%s' is not set at all.",
                   "Try setting '%s' to a value that satisfies the condition"), message, p2id, p2id)
+            } else if (inherits(val, "ContextPV")) {
+              message = sprintf("%s However, %s is a ContextPV. Conditions on ContextPV values default to FALSE / unmet.", message, p2id)
             } else {
               message = sprintf("%s Instead the current parameter value is: %s=%s", message, p2id, val)
             }
@@ -584,7 +623,7 @@ ParamSet = R6Class("ParamSet",
         for (n in names(xs)) {
           p = params[[n]]
           x = xs[[n]]
-          if (inherits(x, "TuneToken")) next
+          if (inherits(x, "TuneToken") || inherits(x, "ContextPV")) next
           if (has_element(p$special_vals, x)) next
           xs[[n]] = p$convert(x)
         }
diff --git a/R/Sampler.R b/R/Sampler.R
index 8b7c5e34..528773cc 100644
--- a/R/Sampler.R
+++ b/R/Sampler.R
@@ -19,7 +19,7 @@ Sampler = R6Class("Sampler",
     #' Note that this object is typically constructed via derived classes,
     #' e.g., [Sampler1D].
     initialize = function(param_set) {
-      assert_param_set(param_set, no_untyped = TRUE)
+      assert_param_set(param_set)
       self$param_set = param_set$clone(deep = TRUE)
     },
 
diff --git a/man/ContextPV.Rd b/man/ContextPV.Rd
new file mode 100644
index 00000000..06349322
--- /dev/null
+++ b/man/ContextPV.Rd
@@ -0,0 +1,39 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/ContextPV.R
+\name{ContextPV}
+\alias{ContextPV}
+\title{ParamSet Value that Depends on Context}
+\usage{
+ContextPV(.fn, ...)
+}
+\arguments{
+\item{.fn}{\code{function}\cr
+Function to be executed in the context where \code{\link{ParamSet}} values
+are retrieved.}
+
+\item{...}{any\cr
+Variable names to make available to function. Functions are run in
+the \code{\link[base:environment]{.GlobalEnv}} scope and only the variables
+named in \code{...} will be available.}
+}
+\description{
+Set a \code{\link{ParamSet}}\verb{$value} slot to this. The \code{.fn} function will
+be called with the respective function arguments. The function argument
+names of \code{.fn} must be a subset of the \code{\link{ParamSet}}'s \verb{$context_available} slot.
+}
+\examples{
+p = ps(x = p_dbl(), y = p_dbl())
+p$context_available = c("a", "x")
+
+b = 10
+
+p$values$x = ContextPV(function(a) a * b, b)
+p$values$y = ContextPV(function(x) x^2)
+# ContextPV uses the value of b right at this moment
+b = 20
+
+p$values$x(1)  # 1 * 10
+
+p$get_values(context = list(a = 10, x = 20))  # using 'a' from context: 10 * 10
+
+}
diff --git a/man/ParamSet.Rd b/man/ParamSet.Rd
index 14fca66c..ca072097 100644
--- a/man/ParamSet.Rd
+++ b/man/ParamSet.Rd
@@ -53,6 +53,12 @@ ps$check(list(d = 2.1, f = "a", i = 3L))
 \item{\code{assert_values}}{(\code{logical(1)})\cr
 Should values be checked for validity during assigment to active binding \verb{$values}?
 Default is \code{TRUE}, only switch this off if you know what you are doing.}
+
+\item{\code{context_available}}{(\code{character})\cr
+Context that \code{\link{ContextPV}} values can rely on being present. When assigning a \code{\link{ContextPV}}
+to a \verb{$values} element, its argument names must be a subset of \verb{$context_available}.
+Conversely, the \code{context} argument of \verb{$get_values()} must contain named elements
+corresponding to all \verb{$context_available} entries.}
 }
 \if{html}{\out{</div>}}
 }
@@ -259,7 +265,8 @@ Only returns values of parameters that satisfy all conditions.
   is_bounded = NULL,
   tags = NULL,
   type = "with_token",
-  check_required = TRUE
+  check_required = TRUE,
+  context = parent.frame()
 )}\if{html}{\out{</div>}}
 }
 
@@ -277,6 +284,10 @@ Return values \code{with_token}, \code{without_token} or \code{only_token}?}
 
 \item{\code{check_required}}{(\code{logical(1)})\cr
 Check if all required parameters are set?}
+
+\item{\code{context}}{(\code{environment} | named \code{list})\cr
+Must have elements named by \verb{$context_available}, which are then given to the
+respective arguments of \code{\link{ContextPV}} values.}
 }
 \if{html}{\out{</div>}}
 }
diff --git a/tests/testthat/test_ContextPV.R b/tests/testthat/test_ContextPV.R
new file mode 100644
index 00000000..77e7d572
--- /dev/null
+++ b/tests/testthat/test_ContextPV.R
@@ -0,0 +1,108 @@
+
+context("ContextPV")
+
+test_that("ContextPV construction", {
+  y = 2
+  fpv = ContextPV(function(x) x * y, y)
+  expect_equal(fpv(10), 20)
+  expect_output(print(fpv), "ContextPV function.*x \\* y.*\\$y.*2")
+})
+
+test_that("ContextPV applied in get_values()", {
+  p = ParamSet$new(list(ParamInt$new("x")))
+  y = 2
+  expect_error({p$values$x = ContextPV(function(x) x * y, y)}, "Argument names of ContextPV Must be a subset of set \\{\\}")
+
+  p$context_available = c("a", "x")
+
+  p$values$x = ContextPV(function(x) x * y, y)
+  expect_output(print(p$values$x), "x \\* y.*\\$y.*2")
+
+  expect_error(p$get_values(), "context.*Must include the elements \\{a,x\\}")
+
+  expect_equal(p$get_values(context = list(x = 10, a = 20)), list(x = 20))
+
+  x = 30
+  a = 20
+  expect_equal(p$get_values(), list(x = 60))  # default context is parent.frame
+
+})
+
+test_that("ContextPV checks range", {
+  p = ParamSet$new(list(ParamInt$new("x", lower = 0, upper = 30)))
+  p$context_available = "x"
+
+  y = 2
+  p$values$x = ContextPV(function(x) x * y, y)
+
+  expect_equal(p$get_values(context = list(x = 10)), list(x = 20))
+  expect_error(p$get_values(context = list(x = 20)), " x resulted in infeasible value.*is not <= 30")
+
+  expect_error(p$get_values(context = list(x = 10.25)), " x resulted in infeasible value.*not 'double'")
+
+})
+
+test_that("ContextPV convert", {
+
+  p = ParamSet$new(list(ParamDbl$new("x", lower = 0, upper = 30)))
+  p$context_available = "x"
+
+  y = 2
+  p$values$x = ContextPV(function(x) x * y, y)
+
+  expect_equal(p$get_values(context = list(x = 10)), list(x = 20))
+  # convert to within range
+  expect_equal(p$get_values(context = list(x = 15.0000000001)), list(x = 30), tolerance = 1e-100)
+})
+
+test_that("ContextPV may not be in variable with dependency", {
+  p = ParamSet$new(list(
+    ParamInt$new("x"),
+    ParamInt$new("y")
+  ))
+  p$add_dep("x", "y", CondEqual$new(0))
+  y = 2
+  expect_error({p$values = list(x = 1, y = 1)}, "can only be set if the following.*y = 0")
+
+  expect_error({p$values = list(x = 1, y = 0)}, NA)
+  expect_error({p$values = list(y = 1)}, NA)
+
+  fpv = ContextPV(function(x) x * y, y)
+  p$context_available = "x"
+  expect_error({p$values = list(y = fpv)}, NA)
+
+  expect_error({p$values = list(x = 1, y = fpv)}, "y is a ContextPV")
+})
+
+test_that("ContextPV in Tuning PS", {
+  p = ParamSet$new(list(
+    ParamInt$new("x"),
+    ParamInt$new("y")
+  ))
+  p$context_available = "scale"
+  p2 = p$search_space(list(
+    x = to_tune(0, 10),
+    y = to_tune(p_dbl(0, 1,
+      trafo = function(x) ContextPV(function(scale) scale * x, x)))
+  ))
+
+  paramval = generate_design_grid(p2, 3)$transpose()[[5]]  # 5, 0.5
+  p$values = paramval
+  expect_equal(p$get_values(context = list(scale = 100)), list(x = 5, y = 50))
+  expect_equal(p$get_values(context = list(scale = 10)), list(x = 5, y = 5))
+  expect_error(p$get_values(context = list(scale = 1)), "infeasible value.*not 'double'")
+
+})
+
+
+test_that("ContextPV with PSC", {
+  p = ps(x = p_dbl())
+  p$context_available = "x"
+  p$set_id = "n"
+  psc = ParamSetCollection$new(list(p))
+  expect_error({psc$values$n.x = ContextPV(function(y) x * 2)}, "Must be a subset of set \\{x\\}")
+  psc$values$n.x = ContextPV(function(x) x * 2)
+
+  expect_equal(p$get_values(context = list(x = 10)), list(x = 20))
+
+})