propegate_values: Partially evaluate a code block with given variable values

In dgkf/scriptgloss: Functionality for creating static scripts from shiny apps

Description

Partially evaluate a code block with given variable values

Usage

propegate_values(code, ..., dots = list(), envir = NULL)

Arguments

code	the code block to use as the basis for evaluation
...	named variables and values to be evaluated within the code
dots	optionally specify additional ellipses names as list
envir	the environment in which subtrees should be evaluated. If missing (the default) an environment as a direct child of the base environment is created with only declarations of the ellipses arguments and used for evaluation of the tree.

Value

the input code block with specified variables partially applied

Examples

codeblock <- quote({
  # inserting values into a code block
  my_function_1 <- function() {
    print(paste(input$a, input$b, other_var))
  }

  my_function_2 <- function() {
    print(input$a)
    print(input$b)
  }
  
  # example of behavior when a value is not present
  my_function_2 <- function() {
    print(input$c + other_var)
  }
  
  # example of variable getting declared in a local frame
  my_function_3 <- function() {
    input <- 3
    print(input)
  }
  
  # example of a variable getting declared in a parent frame
  input <- 4
  my_function_4 <- function() {
    print(input)
  }
})


codeblock <- quote({
  output$test <- function() { print("a") }
  output$test()
})

scriptgloss:::propegate_values(
    codeblock, 
    input = list(
      a = list(1, 2, 3, 4), 
      b = "b"))

dgkf/scriptgloss documentation built on June 8, 2019, 8:43 p.m.