brodieG

In writing a string manipulation library I ran into what I think is a bug in how substr handles malformed UTF8 strings. I was testing corner cases, in particular the following case of a string that ends with the first byte of a UTF8 sequence:

string <- "abc\xEE"    # \xEE indicates the start of a 3 byte UTF-8 sequence
Encoding(string) <- "UTF-8"
substr(string, 1, 10)

When run under valgrind with level 2 instrumentation, we get:

> string <- "abc\xEE"    # \xEE indicates the start of a 3 byte UTF-8 sequence

brodieG

Starts off with:

On Sunday, March 25, 2018, 3:03:26 AM EDT, Prof Brian Ripley ripley@stats.ox.ac.uk wrote: See https://cran.r-project.org/web/checks/check_results_fansi.html . valgrind is reporting the use of uninitialized strings.

Please correct ASAP and before April 20 to safely retain the package on CRAN.

We look at the fansi valgrind test run, and see errors like the following:

brodieG

# Test your passwords against the "Pwned Passwords" V2 database
# as described in <https://www.troyhunt.com/ive-just-launched-pwned-passwords-version-2/>
#
# USE AT YOUR OWN RISK.  I MAKE NO GUARANTEES THAT THIS CODE
# PROTECTS YOUR PASSWORDS.
#
# requires `digest` package (thanks @eddelbuettel)
#
# This code is published under the GPL-2 License
# <https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>

brodieG

State	GDP
California 	2622731835.09
Colorado 	322644574.0735
Florida 	926049669.5
Hawaii 	84671360.816540
Mississippi 	108495598.4982
Montana 	46227205.9303
New Mexico 	93594132.5471
New York 	1500055297.281
Tennessee 	331868896.1153

brodieG

`%>%` <- function(lhs, rhs) UseMethod("%>%")
`%>%.default` <- magrittr::`%>%`
`%>%.gg` <- function(lhs, rhs) ggplot2:::`+.gg`(lhs, rhs)

# WARNING: IF YOU DO THE FOLLOWING YOU SHOULD PROBABLY EXIT AND
# RESTART YOUR R SESSION SO THAT MAGRITTR IS RESTORED TO ITS
# ORIGINAL STATE.

assignInNamespace("is_pipe", 
  function (pipe) 

brodieG

blinkyverse_logo <- function() {
  logo <- c(tidyverse::tidyverse_logo(unicode=FALSE))

  logoa <- gsub("*", "\u2b22", logo, fixed=TRUE)
  logoa <- gsub("o", "\u2b21", logoa, fixed=TRUE)

  logob <- gsub("o", "\u2b22", logo, fixed=TRUE)
  logob <- gsub("*", "\u2b21", logob, fixed=TRUE)
  logob <- gsub(".", "*", logob, fixed=TRUE)

brodieG

date.2 <- rep(Sys.Date(), 2) # length 2 date object
date.1 <- date.2[1]
valid_identifier_regex <- function() "^\\w+$"

date_between <- function(column_name, date_range) {
  vetr(
    character(1L) && grepl(valid_identifier_regex(), .),
    (date.2 || date.1) && !anyNA(.)
  )
  TRUE

brodieG

Snippet used to compare valaddin to vetr performance. This is not actually generated as part of vignettes because it will then require valaddin as part of the build package, which brings in unwanted dependencies (via suggests) that make the build process slow on travis.

secant <- function(f, x, dx) (f(x + dx) - f(x)) / dx

secant_valaddin <- valaddin::firmly(secant, list(~x, ~dx) ~ is.numeric)

brodieG

reg <- "(A|B)*"   # overflow
reg <- "([AB])*"  # works
string <- paste0(rep("A", 1e4), collapse="")
grep(reg, string, perl=TRUE)

brodieG

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application: