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mages / ChainLadder

Claims reserving models in R
https://mages.github.io/ChainLadder/
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Print methods should return their argument invisibly #56

Closed msenn closed 6 years ago

msenn commented 6 years ago

Issue

Some print methods do not return their argument unchanged. For example:

library(ChainLadder)
mcl <- MackChainLadder(RAA)

# Printing changes it's argument
mcl_print <- print(MackChainLadder(RAA))
identical(mcl, mcl_print)              # Returns FALSE

# Brackets change the assinged object
(mcl_brackets <- MackChainLadder(RAA))
identical(mcl, mcl_brackets)           # Returns FALSE

# If object is assigned to a name before printing / brackets, results differ
mcl_print2 <- print(mcl)
identical(mcl_print, mcl_print2)       # Returns TRUE

(mcl_brackets2 <- mcl)
identical(mcl_brackets, mcl_brackets2) # Returns FALSE

This behaviour can lead to confusion and is not in line with the print generic's documentation (?print):

print prints its argument and returns it invisibly (via invisible(x))

Expected behaviour

The behaviour I was expecting, illustrated with summary():

mtc_smry <- summary(mtcars)

# Printing returns it's argument
mtc_smry_print <- print(summary(mtcars))
identical(mtc_smry, mtc_smry_print)              # Returns TRUE

# Brackets have no impact
(mtc_smry_brackets <- summary(mtcars))
identical(mtc_smry, mtc_smry_brackets)           # Returns TRUE

# No impact if object is assigned to a name before printing / brackets
mtc_smry_print2 <- print(mtc_smry)
identical(mtc_smry_print, mtc_smry_print2)       # Returns TRUE

(mtc_smry_brackets2 <- mtc_smry)
identical(mtc_smry_brackets, mtc_smry_brackets2) # Returns TRUE

System info

I am using the current GitHub version of ChainLadder. Here's my sessionInfo()

R version 3.5.0 (2018-04-23)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Red Hat Enterprise Linux Server 7.5 (Maipo)

Matrix products: default
BLAS: /opt/R/3.5.0/lib64/R/lib/libRblas.so
LAPACK: /opt/R/3.5.0/lib64/R/lib/libRlapack.so

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8       
 [4] LC_COLLATE=en_US.UTF-8     LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                  LC_ADDRESS=C              
[10] LC_TELEPHONE=C             LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

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

other attached packages:
[1] ChainLadder_0.2.6

loaded via a namespace (and not attached):
 [1] biglm_0.9-1       statmod_1.4.30    zoo_1.8-2         tidyselect_0.2.4  purrr_0.2.5      
 [6] reshape2_1.4.3    splines_3.5.0     haven_1.1.1       lattice_0.20-35   carData_3.0-1    
[11] colorspace_1.3-2  stats4_3.5.0      yaml_2.1.19       rlang_0.2.1       pillar_1.2.3     
[16] foreign_0.8-70    glue_1.3.0        tweedie_2.3.2     readxl_1.1.0      bindrcpp_0.2.2   
[21] bindr_0.1.1       plyr_1.8.4        stringr_1.3.1     munsell_0.5.0     cplm_0.7-7       
[26] gtable_0.2.0      cellranger_1.1.0  zip_1.0.0         expint_0.1-4      coda_0.19-1      
[31] systemfit_1.1-22  rio_0.5.10        forcats_0.3.0     lmtest_0.9-36     curl_3.2         
[36] Rcpp_0.12.17      scales_0.5.0      abind_1.4-5       ggplot2_3.0.0     stringi_1.2.3    
[41] openxlsx_4.1.0    dplyr_0.7.6       grid_3.5.0        tools_3.5.0       sandwich_2.4-0   
[46] magrittr_1.5      lazyeval_0.2.1    tibble_1.4.2      car_3.0-0         pkgconfig_2.0.1  
[51] MASS_7.3-50       Matrix_1.2-14     data.table_1.11.4 actuar_2.3-1      assertthat_0.2.0 
[56] minqa_1.2.4       R6_2.2.2          nlme_3.1-137      compiler_3.5.0