`seq.int()` error if Stata Code contains `exit`

[MetzgerSK]

R: 4.1.3 64-bit, RStata: 1.1.1, Stata: 17.0 MP6, Win10
(This issue originates from the same line as issues #6, #11, and #12 , but the reason the error occurs is different.)

If the Stata code has an exit statement, stata() will exit with an error when R tries to parse the Stata log's output.

The culprit is stata()'s lines 74-75. The second cutpoint that seq.int() uses will never be be defined because exit precludes line 48's second cut_me_comment from getting printed to Stata's Results pane. I verified this by checking stataLog's contents (included at very end, to help with readability).

This came up in a more complex use case of mine, but for a MWE:

# Assumes Stata path/Stata version set already
library(RStata)

# Base code
stataCode <-
    "
      // load something arbitrarily
      sysuse auto, clear

      // do stuff
      sum mpg

      // do other stuff
      describe

      // if the kill condition's met, stop executing and throw control back to R
      if(`killCondit'==1){
          exit
      }

      // Do a final thing
      tab foreign
    "
      
# Kill condition code - condition won't be met
localAppd <-
    "// an arbitrary local macro, to serve as the stop condition
    local killCondit = 0"

# !! - This will run fine
stata(paste0(localAppd, stataCode))

# Kill condition code - condition WILL be met
localAppd <-
    "// an arbitrary local macro, to serve as the stop condition
    local killCondit = 1"

# !! - This will throw an error
stata(paste0(localAppd, stataCode))

In my specific case, I could implement a workaround by tweaking the conditional and the code encapsulated by it:

stataCode <-
    " // load something arbitrarily
      sysuse auto, clear

      // do stuff
      sum mpg

      // do other stuff
      describe

      ** THIS IS WHAT CHANGED: NEGATE THE CONDITIONAL AND WRAP ALL THE SUBSQ
      ** CODE INSIDE THE IF()
      // if the kill condition's not met, continue executing
      if(`killCondit'!=1){

          // Do a final thing
          tab foreign
      }
    "

# !! - Will now run fine
stata(paste0(localAppd, stataCode))

If others run into the same problem, I'm unsure whether they'd be able to do the same. I suspect it'd depend on the specifics for that use case.

Returning to the root cause (exit): I wasn't sure if this was intended behavior from stata() (and that we, as users, simply needed to be more mindful) or an overlooked edge case. I didn't see anything in stata()'s help file or the GitHub readme suggesting it was the first, so wanted to bring it to your attention.

Thanks for such a useful package!

---

stataLog contents, after executing stata(), line 73:

Browse[2]> stataLog
 [1] ""
 [2] "  ___  ____  ____  ____  ____ ®"
 [3] " /__    /   ____/   /   ____/      17.0"
 [4] "___/   /   /___/   /   /___/       MP—Parallel Edition"
 [5] ""
 [6] " Statistics and Data Science       Copyright 1985-2021 StataCorp LLC"
 [7] "                                   StataCorp"
 [8] "                                   4905 Lakeway Drive"
 [9] "                                   College Station, Texas 77845 USA"
[10] "                                   800-STATA-PC        https://www.stata.com"
[11] "                                   979-696-4600        stata@stata.com"
[12] ""
[13] "Stata license: Single-user 6-core  perpetual"
[14] "Serial number: XXX"
[15] "  Licensed to: XXX"
[16] "               XXX"
[17] ""
[18] "Notes:"
[19] "      1. Stata is running in batch mode."
[20] "      2. Unicode is supported; see help unicode_advice."
[21] "      3. More than 2 billion observations are allowed; see help obs_advice."
[22] "      4. Maximum number of variables is set to 5,000; see help set_maxvar."
[23] ""
[24] ". do RStata.do "
[25] ""
[26] ". set more off"
[27] ". "
[28] ". "
[29] ". "
[30] ". capture noisily {"
[31] ". /*RSTATA: cut me here*/"
[32] ". // an arbitrary local macro, to serve as the stop condition"
[33] ".     local killCondit = 1 "
[34] ". "
[35] ". "
[36] ". "
[37] ".       // load something arbitrarily"
[38] ".       sysuse auto, clear"
[39] "(1978 automobile data)"
[40] ". "
[41] ".       // do stuff"
[42] ".       sum mpg"
[43] ""
[44] "    Variable |        Obs        Mean    Std. dev.       Min        Max"
[45] "-------------+---------------------------------------------------------"
[46] "         mpg |         74     21.2973    5.785503         12         41"
[47] ". "
[48] ".       // do other stuff"
[49] ".       describe"
[50] ""
[51] "Contains data from C:\\Program Files\\Stata17\\ado\\base/a/auto.dta"
[52] " Observations:            74                  1978 automobile data"
[53] "    Variables:            12                  13 Apr 2020 17:45"
[54] "                                              (_dta has notes)"
[55] "-------------------------------------------------------------------------------"
[56] "Variable      Storage   Display    Value"
[57] "    name         type    format    label      Variable label"
[58] "-------------------------------------------------------------------------------"
[59] "make            str18   %-18s                 Make and model"
[60] "price           int     %8.0gc                Price"
[61] "mpg             int     %8.0g                 Mileage (mpg)"
[62] "rep78           int     %8.0g                 Repair record 1978"
[63] "headroom        float   %6.1f                 Headroom (in.)"
[64] "trunk           int     %8.0g                 Trunk space (cu. ft.)"
[65] "weight          int     %8.0gc                Weight (lbs.)"
[66] "length          int     %8.0g                 Length (in.)"
[67] "turn            int     %8.0g                 Turn circle (ft.)"
[68] "displacement    int     %8.0g                 Displacement (cu. in.)"
[69] "gear_ratio      float   %6.2f                 Gear ratio"
[70] "foreign         byte    %8.0g      origin     Car origin"
[71] "-------------------------------------------------------------------------------"
[72] "Sorted by: foreign"
[73] ". "
[74] ".       // if the kill condition's met, stop executing and throw control back t"
[75] "> o R"
[76] ".       if(`killCondit'==1){"
[77] ".           exit"
[78] ""
[79] "end of do-file"