Shiny values within a function from input - r

Question

I am working on a shiny app, where I need input values to show up in a function.
What I am trying to do is to somehow extract names and values from input, like CL=4, V1=3, and feed them in a function that I need to feed into a model in server later on. The model I am working on only takes function format. Below is my code.
UI:
#Set up
rm(list=ls())
library(shiny)
library(shinydashboard)
library(shinyBS)
library(dplyr)
#Design sidebar
sidebar <- dashboardSidebar(width = 200, collapsed=TRUE,
sidebarMenu(id="tabs",
menuItem("Simulations", tabName = "Sims", icon = icon("line-chart"), selected=TRUE),
menuItem("Placeholder", tabName = "Place", icon = icon("square-o"))
))
#Design body
body <- dashboardBody(
tabItems(
tabItem(tabName = "Sims",
box(collapsible=TRUE, width = 3, status = "success", solidHeader = T, title="Select Your Model",
radioButtons(inputId="PK_Model", label = "PK Model", selected="One_Comp",
choices = c("1 Compartment"="One_Comp", "2 Compartment"="Two_Comp")),
radioButtons(inputId="Clearance_Model",label ="Clearance Mechanism", selected="Linear",
choices = c("Linear"="Linear"))),
box(collapsible=TRUE, status = "success", solidHeader = T, title="Enter Parameter Estimates",
conditionalPanel(condition = "input.Clearance_Model == 'Linear'",
numericInput(label="Clearance (Linear) (CL; L/day)", inputId="CL", min = 0, max = NA, value = 0),
numericInput(label="Central volume of distribution (V1; L)", inputId="V1", min = 0, max = NA, value = 0)),
conditionalPanel(condition = "input.PK_Model == 'Two_Comp'",
numericInput(label="Inter-compartment clearance (Q; L/day)", inputId="Q", min = 0, max = NA, value = 0),
numericInput(label="Peripheral volume of distribution (V2; L)", inputId="V2", min = 0, max = NA, value = 0))),
box(collapsible=T, width=2, status = "success", solidHeader = T, title="Run",
actionButton('gosim','Run Sims',class='btn btn-info', icon=icon('play-circle-o','fg-lg'))),
box(width=5, status = "success", solidHeader = T, title="Simulated", textOutput('testprint')))))
#Show title and the page (includes sidebar and body)
dashboardPage(skin=c("blue"),
dashboardHeader(titleWidth=900, title = "Shiny Test"),
sidebar, body)
UPDATED:
Following PoGibas's answer below, I updated server code to following, but result does not look like what I need.
Server:
library(shiny)
library(shinydashboard)
library(shinyBS)
library(RxODE)
library(parallel)
library(ggplot2)
test <- function (N1, N2, N3, N4) {
mypar <- function(lKa, lKdeg, N1, N2, N3, N4){
Ka=exp(lKa)
Kdeg=exp(lKdeg)
V1=N1
CL=N2
Q=N3
V2=N4}
return(mypar)
}
shinyServer(function(input, output, session){
mypar <-eventReactive(input$goSimPH20, {
N1=as.numeric(input$V1)
N2=as.numeric(input$CL)
N3=as.numeric(input$Q)
N4=as.numeric(input$V2)
par1 = test(N1, N2, N3, N4)
return(par1)
})
output$testprint <- renderText(mypar())
})
What I need result to look like when I call mypar() within server is as below:
test <- function (lKa, lKdeg, V1, CL, Q, V2) {
Ka=exp(lKa)
Kdeg=exp(lKdeg)
V1=xx
V2=xx
CL=xx
Q=xx
}
xx can be any user supplied value in UI.

Answer 1

I simplified server part to this:
test <- function (V1 = 1, CL = 2, lA = 1, lB = 2) {
return(lA + lB + V1 + CL)
}
shinyServer(function(input, output, session) {
mypar <- reactive({
V1 = as.numeric(input$V1)
CL = as.numeric(input$CL)
return(test(V1, CL))
})
output$testprint <- renderText(mypar())
})
In test function add your wanted formula. User input is extracted using V1 = as.numeric(input$V1) and passed to test using test(V1, CL).