Date last run: 11Mar2020 (correction typo)
Introduction
Often having problems with non-standard evaluation I decided to read Hadley Wickham Advanced R chapters about metaprogramming.
Problem
An example of a problem I met was the case that I wanted to silently load the packages glue and purrr with the function HOQCutil::silent_library. This function accepted both a name and a character string (i.e as well knitr as 'knitr' ) but apparently not a list element containing the name of a package. With HOQCutil_0.1.16 we got the following results:
packages_to_load <- c('glue','purrr')
HOQCutil::silent_library
#> function (package_name,mywarnings = FALSE) {
#> suppressWarnings({
#> suppressPackageStartupMessages({
#> library(
#> as.character(as.name(substitute(package_name))) ,
#> character.only = TRUE,
#> warn.conflicts = mywarnings,
#> quietly = !mywarnings,
#> verbose = mywarnings
#> )
#> })
#> })
#> }
#> <bytecode: 0x0000000017edff08>
#> <environment: namespace:HOQCutil>
HOQCutil::silent_library(knitr)
HOQCutil::silent_library('knitr')
purrr::walk(packages_to_load,HOQCutil::silent_library)
#> Error in as.name(substitute(package_name)): 'pairlist' object cannot be coerced to type 'symbol'
Solution
Reading the metaprogramming chapter I saw that I could use some rlang functions to fix the HOQCutil::silent_library function. It works now for all cases: a character string, a name and a variable with as value a character or name. The function is now included in the HOQCutil package (version 0.1.17). The following chunk shows how this works:
HOQCutil::silent_library
#> function (package_name,mywarnings = FALSE) {
#> package_name2 <- rlang::enexpr(package_name)
#> if (rlang::is_symbol(package_name2)) {
#> package_name <- rlang::as_string(package_name2)
#> }
#> suppressWarnings({
#> suppressPackageStartupMessages({
#> library(
#> package_name,
#> character.only = TRUE,
#> warn.conflicts = FALSE,
#> quietly = TRUE,
#> verbose = FALSE
#> )
#> })
#> })
#> }
#> <bytecode: 0x00000000186aa9d0>
#> <environment: namespace:HOQCutil>
search()
#> [1] ".GlobalEnv" "package:stats" "package:graphics"
#> [4] "package:grDevices" "package:utils" "package:datasets"
#> [7] "package:methods" "Autoloads" "package:base"
HOQCutil::silent_library(tabr)
HOQCutil::silent_library('tabraux')
packages_to_load <- c('glue','FactoMineR','dplyr')
purrr::walk(packages_to_load[1:2],HOQCutil::silent_library)
HOQCutil::silent_library(packages_to_load[[3]])
search()
#> [1] ".GlobalEnv" "package:dplyr" "package:FactoMineR"
#> [4] "package:glue" "package:tabraux" "package:tabr"
#> [7] "package:stats" "package:graphics" "package:grDevices"
#> [10] "package:utils" "package:datasets" "package:methods"
#> [13] "Autoloads" "package:base"
While testing I realized that using the argument mywarnings=TRUE makes no sense. For compatibility reasons I will keep this argument but ignore it.
Session Info
This document was produced on 11Mar2020 with the following R environment:
#> R version 3.6.0 (2019-04-26)
#> Platform: x86_64-w64-mingw32/x64 (64-bit)
#> Running under: Windows 10 x64 (build 18363)
#>
#> Matrix products: default
#>
#> locale:
#> [1] LC_COLLATE=English_United States.1252
#> [2] LC_CTYPE=English_United States.1252
#> [3] LC_MONETARY=English_United States.1252
#> [4] LC_NUMERIC=C
#> [5] LC_TIME=English_United States.1252
#>
#> attached base packages:
#> [1] stats graphics grDevices utils datasets methods base
#>
#> other attached packages:
#> [1] dplyr_0.8.5 FactoMineR_2.3 glue_1.3.1 tabraux_0.0.3 tabr_0.4.1
#>
#> loaded via a namespace (and not attached):
#> [1] Rcpp_1.0.3 pillar_1.4.3 compiler_3.6.0
#> [4] tools_3.6.0 digest_0.6.23 evaluate_0.14
#> [7] tibble_2.1.3 lifecycle_0.1.0 gtable_0.3.0
#> [10] lattice_0.20-38 pkgconfig_2.0.3 rlang_0.4.5
#> [13] ggrepel_0.8.1 xfun_0.10 stringr_1.4.0
#> [16] knitr_1.28 cluster_2.0.8 flashClust_1.01-2
#> [19] grid_3.6.0 tidyselect_0.2.5 scatterplot3d_0.3-41
#> [22] R6_2.4.1 rmarkdown_2.1 purrr_0.3.3
#> [25] ggplot2_3.3.0 magrittr_1.5 scales_1.1.0
#> [28] htmltools_0.4.0 leaps_3.0 MASS_7.3-51.4
#> [31] assertthat_0.2.1 colorspace_1.4-1 stringi_1.4.6
#> [34] HOQCutil_0.1.18 munsell_0.5.0 crayon_1.3.4