wch

# This code uses later's C API to schedule callbacks as quickly as possible, and
# it tests if the callbacks execute in the same order that they are scheduled.
# In Docker on Mac, they sometimes do not.

docker run --rm -ti rocker/shiny /bin/bash
R
install.packages(c('cpp11', 'later', 'brio', 'callr', 'cli', 'decor', 'desc',
  'tibble', 'vctrs'))

library(cpp11)

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docker run --rm -ti --security-opt seccomp=unconfined wch1/r-debug

# =====================================================================
# Setup
# =====================================================================
RD -e 'install.packages(c("cpp11", "decor", "igraph"))'
RD -e 'remotes::install_github("r-lib/memtools", build_manual = FALSE, build_vignettes = FALSE)'


# ==============================================================================

wch

Keybase proof

I hereby claim:

• I am wch on github.
• I am winston (https://keybase.io/winston) on keybase.
• I have a public key ASBIcD-b7Mr5y30DdA4AfVp_I263JfDKgLboP2DYCHpfvwo

To claim this, I am signing this object:

wch

library(rlang)
library(pryr)

# ===========================
# Normal quosures
# ===========================
# as_function() with a quosure: OK
a <- 1
x <- quo(a + 10)
a <- 2

wch

library(digest)
library(promises)
library(cache)

# Given a list with items named `value` and `visible`, return `x$value` either
# visibly, or invisibly, depending on the value of `x$visible`.
valueWithVisible <- function(x) {
  if (x$visible) x$value else invisible(x$value)
}

wch

library(profvis)
library(microbenchmark)
library(memoise)
library(digest)

# Bare function
f <- function(a, b) {
  a + b
}

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library(httpuv)

# Create a web server app which returns the time and prints out the value of
# a header named "test-header".
handle_request <- function(req) {
  list(
    status = 200L,
    headers = list('Content-Type' = 'text/plain'),
    body = paste0(
      "The time is: ", Sys.time(), "\n",

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> install.packages("Rcpp")
Installing package into ‘/Users/winston/R/3.6’
(as ‘lib’ is unspecified)
trying URL 'https://cloud.r-project.org/bin/macosx/el-capitan/contrib/3.6/Rcpp_1.0.4.tgz'
Content type 'application/x-gzip' length 3124401 bytes (3.0 MB)
==================================================
downloaded 3.0 MB


The downloaded binary packages are in

wch

This is an example of C code calling an R function, by building a function call and then evaluating it.

wch

# First, need to install crandb
# devtools::install_github('r-hub/crandb')

# Memoize crandb::package because we end up making a lot of repetitive calls.
package <- memoise::memoise(crandb::package)

# Get a list of built-in packages. We don't need to check the version
# information for these packages.
builtin_pkgs <- memoise::memoise(function() {
  pkgs <- installed.packages()