Closes #880. eval(parse(.)) issue in j

R/data.table.R

@@ -25,8 +25,11 @@ deconstruct_and_eval = function(expr, envir = parent.frame(), enclos = parent.fr
     }
     ff <- function(m) {
         if (is.call(m)) {
-            if (m[[1L]] == quote(eval)) 
-                deconstruct_and_eval(eval(m[[2L]], envir, enclos), envir, enclos) 
+            if (m[[1L]] == quote(eval))
+                # fix for #880. Hopefully this resolve the eval(parse(.)) issue for good.
+                if (is.call(m[[2L]]) && m[[2L]][[1L]] == quote(parse)) 
+                    deconstruct_and_eval(m, envir, enclos)
+                else deconstruct_and_eval(eval(m[[2L]], envir, enclos), envir, enclos)
             else deconstruct_and_eval(m, envir, enclos)
         } else m
     }

README.md

@@ -42,7 +42,8 @@
   11. `format.ITime` now handles negative values properly. Closes [#811](https://github.com/Rdatatable/data.table/issues/811). Thanks to @StefanFritsch for the report along with the fix!
 
   12. Compatibility with big endian machines (e.g., SPARC and PowerPC) is restored. Most Windows, Linux and Mac systems are little endian; type `.Platform$endian` to confirm.
-
+
+  13. `DT[, LHS := RHS]` with RHS is of the form `eval(parse(text = foo[1]))` referring to columns in `DT` is now handled properly. Closes [#880](https://github.com/Rdatatable/data.table/issues/880). Thanks to tyner.
 
 #### NOTES
 

inst/tests/tests.Rraw

@@ -5361,6 +5361,11 @@ x = c(1L, -1L, -3700L)
 class(x) = "ITime"
 test(1388, as.character(x), c("00:00:01", "-00:00:01", "-01:01:40"))
 
+# Fix for #880. Another eval(parse(.)) issue.
+DT <- as.data.table(iris)
+DT[, foo := "Species"]
+test(1389, copy(DT)[,bar := eval(parse(text=foo[1]), envir=.SD)], copy(DT)[, bar := Species])
+
 ##########################