Error when using purrr to map the dfm() function to a list

[EricHe98]

The map() function in the purrr package throws an error when passed a list to convert to dfms. The error appears whether the input is a list of characters or corpora.

a <- "a"
b <- "b"
c <- list(a, b)
map(c, dfm)

# Error in if (who_called_me_first(sys.calls(), "dfm") == "corpus") { : 
missing value where TRUE/FALSE needed

a <- corpus("a")
b <- corpus("b")
c <- list(a, b)
map(c, dfm)
# Error in if (who_called_me_first(sys.calls(), "dfm") == "corpus") { : 
  missing value where TRUE/FALSE needed

This issue does not occur with other quanteda functions, e.g. corpus().

a <- "a"
b <- "b"
c <- list(a, b)
map(c, corpus)
# [[1]]
# Corpus consisting of 1 document and 0 docvars.

# [[2]]
# Corpus consisting of 1 document and 0 docvars.

[EricHe98]

Oh, and here is the session info.

> sessionInfo()
R version 3.3.3 (2017-03-06)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200)

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252    LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                           LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] reshape2_1.4.2  bindrcpp_0.2    readtext_0.50   stringr_1.2.0   purrr_0.2.3     dplyr_0.7.2     quanteda_0.99   devtools_1.13.3

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.12        git2r_0.19.0        plyr_1.8.4          bindr_0.1           tools_3.3.3         digest_0.6.12      
 [7] lubridate_1.6.0     memoise_1.1.0       tibble_1.3.3        gtable_0.2.0        lattice_0.20-34     pkgconfig_2.0.1    
[13] rlang_0.1.2         Matrix_1.2-8        fastmatch_1.1-0     curl_2.8.1          withr_2.0.0         httr_1.3.0         
[19] knitr_1.17          grid_3.3.3          glue_1.1.1          data.table_1.10.4   R6_2.2.2            ggplot2_2.2.1      
[25] magrittr_1.5        scales_0.4.1        assertthat_0.2.0    colorspace_1.3-2    stringi_1.1.5       RcppParallel_4.3.20
[31] lazyeval_0.2.0      munsell_0.4.3