1. 01|# Double nested function/n
02|z <- 8
03|y <- 7
04|u <- 2
05|n <- function(x) {
06| y <- x
07| function(v) {
08| z + y + v # which z, y are used?
09| }
10|}
11|z <- 1
12|y <- 5
13|u <- 4
14|cat("n(y)(u)=",n(y)(u),"\n",sep="")
15|#
2. 01|# Nested functions, lexical scoping
02|k1 <- function(x) {
03| k2 <- function(z) {
04| return(x * z)
05| }
06| return(k2)
07|}
08|cat("k1(7)(9)=",k1(7)(9),"\n",sep="")
09|#
3. 01|# Inner closure
02|u <- 1
03|y <- 10
04|z <- 4
05|k2 <- function(u) {
06| k1 <- function(u) {
07| u <<- 3
08| y <<- 8
09| z <<- 9
10| k3 <- function(y) {
11| y * 10
12| }
13| k3(u) + 10
14| }
15| k1(u) * z
16|}
17|cat("k2(4)=",k2(4),"\n",sep='')
18|#
4. 01|# Double nested function/n
02|y <- 3
03|u <- 6
04|x <- 2
05|n <- function(z) {
06| u <- z
07| function(v) {
08| y + u + v # which y, u are used?
09| }
10|}
11|y <- 5
12|u <- 0
13|x <- 10
14|cat("n(u)(x)=",n(u)(x),"\n",sep="")
15|#
5. 01|# Double nested function using global x/k3
02|x <- 2
03|k3 <- function( ) {
04| function( ) x
05|}
06|x <- 9
07|cat("k3( )( )=",k3( )( ),"\n",sep="")
08|#
6. 01|# Double nested function using global y/k3
02|x <- 2
03|y <- 3
04|k3 <- function(x) {
05| function( ) {
06| x + y # which x is used (global x or k3(x))?
07| }
08|}
09|x <- 6
10|y <- 9
11|cat("k3(1)( )=",k3(1)( ),"\n",sep="")
12|#
7. 01|# Two functions, lexical scoping
02|a <- 1
03|k2 <- function(y) {
04| a * y
05|}
06|a <- 10
07|k3 <- function(x) {
08| a <- 100
09| k2(x)
10|}
11|cat("k3(3)=",k3(3),"\n",sep="")
12|#
8. 01|# Double nested identity function/k2
02|y <- 4
03|k2 <- function(y) { # y unused
04| function(y) y
05|}
06|y <- 10
07|cat("k2(y)(y)=",k2(y)(y),"\n",sep="")
08|#
9. 01|# Global modified, local returned.
02|y <- 6
03|u <- 2 # unused
04|k3 <- function(u){
05| y <<- u + 5
06| y # local y returned
07|}
08|cat("k3(1)=",k3(1),'\n',sep="")
09|#
10. 01|# Triple nested function/k1
02|k1 <- function(x) {
03| k2 <- function(x) {
04| k3 <- function(x) {
05| x + 3
06| }
07| k3(x) + 5
08| }
09| k2(x) + 5
10|}
11|cat("k1(10)=",k1(10),"\n",sep="")
12|#
11. 01|# Double nested identity function/k3
02|x <- 7
03|k3 <- function(x) { # x unused
04| function(x) x
05|}
06|x <- 2
07|cat("k3(x)(x)=",k3(x)(x),"\n",sep="")
08|#
12. 01|# Inner closure
02|z <- 1
03|u <- 7
04|y <- 4
05|k2 <- function(z) {
06| k1 <- function(z) {
07| z <<- 8
08| u <<- 0
09| y <<- 6
10| k3 <- function(u) {
11| u * 10
12| }
13| k3(z) + 7
14| }
15| k1(z) * y
16|}
17|cat("k2(4)=",k2(4),"\n",sep='')
18|#
13. 01|# Double nested function/n
02|y <- 9
03|z <- 2
04|u <- 7
05|n <- function(x) {
06| z <- x
07| function(v) {
08| y + z + v # which y, z are used?
09| }
10|}
11|y <- 10
12|z <- 0
13|u <- 8
14|cat("n(z)(u)=",n(z)(u),"\n",sep="")
15|#
14. 01|# Double nested function using global u/k2
02|y <- 1
03|u <- 2
04|k2 <- function(y) {
05| function( ) {
06| y + u # which y is used (global y or k2(y))?
07| }
08|}
09|y <- 5
10|u <- 4
11|cat("k2(6)( )=",k2(6)( ),"\n",sep="")
12|#
15. 01|# Closure substractor
02|k2 <- function(y=0) {
03| function(z) {
04| z - y
05| }
06|}
07|cat("k2(6)(0)=",k2(6)(0),"\n")
08|#
16. 01|# Nested functions, lexical scoping
02|k2 <- function(x) {
03| k1 <- function(u) {
04| return(x * u)
05| }
06| return(k1)
07|}
08|cat("k2(7)(9)=",k2(7)(9),"\n",sep="")
09|#
17. 01|## Global y returned
02|y <- 9
03|n <- function(y){
04| y <<- y + 1
05|}
06|cat("n(6)=",n(6),'\n',sep="")
07|#
18. 01|# Triple nested function/k3
02|k3 <- function(x) {
03| k2 <- function(x) {
04| k1 <- function(x) {
05| x + 9
06| }
07| k1(x) + 10
08| }
09| k2(x) + 10
10|}
11|cat("k3(4)=",k3(4),"\n",sep="")
12|#
19. 01|# Nested functions, lexical scoping
02|k2 <- function(u) {
03| k3 <- function(y) {
04| return(u * y)
05| }
06| return(k3)
07|}
08|cat("k2(7)(9)=",k2(7)(9),"\n",sep="")
09|#
20. 01|# Nested functions, lexical scoping
02|k3 <- function(u) {
03| k2 <- function(x) {
04| return(u * x)
05| }
06| return(k2)
07|}
08|cat("k3(7)(9)=",k3(7)(9),"\n",sep="")
09|#
