Internal variable names now have prefix .listenv_var_; assign():ing…

… variables of such names for other purpose is now invalid [#6]

NEWS

@@ -1,7 +1,7 @@
 Package: listenv
 ================
 
-Version: 0.4.0-9000 [2015-10-07]
+Version: 0.4.0-9000 [2015-10-17]
 o Add support for assigning elements when creating list environment
   similarly how to lists work, e.g. x <- listenv(a=1, b=2).
 o DEPRECATED: Deprecated x <- listenv(length=n). Instead use 

R/get_variable.R

@@ -51,8 +51,8 @@ get_variable.listenv <- function(x, name, mustExist=FALSE, create=!mustExist, ..
       extra <- rep(NA_character_, times=i-length(map))
       map <- c(map, extra)
     }
-    ## Create internal variable name
-    var <- tempvar(value=NULL, envir=x, inherits=FALSE)
+    ## Create internal variable
+    var <- new_variable(x, value=NULL)
     map[i] <- var
   }
 

R/listenv.R

@@ -30,13 +30,15 @@ listenv <- function(...) {
   }
 
   ## Allocate internal variables
-  maps <- sprintf("var%004d", seq_len(nargs))
+  maps <- sprintf(".listenv_var_%d", seq_len(nargs))
   names(maps) <- names
   for (kk in seq_len(nargs)) {
     assign(maps[kk], value=args[[kk]], envir=env, inherits=FALSE)
   }
   metaenv$.listenv.map <- maps
 
+  assign(".listenv_var_count", nargs, envir=env, inherits=FALSE)
+
   class(env) <- c("listenv", class(env))
 
   env
@@ -315,6 +317,21 @@ as.list.listenv <- function(x, ...) {
 }
 
 
+new_variable <- function(envir, value) {
+  count <- get(".listenv_var_count", envir=envir, inherits=FALSE)
+
+  count <- count + 1L
+  name <- sprintf(".listenv_var_%f", count)
+
+  if (!missing(value)) {
+    assign(name, value, envir=envir, inherits=FALSE)
+  }
+
+  assign(".listenv_var_count", count, envir=envir, inherits=FALSE)
+
+  name
+} # new_variable()
+
 
 assign_by_name <- function(...) UseMethod("assign_by_name")
 
@@ -387,9 +404,8 @@ assign_by_index.listenv <- function(x, i, value) {
       map <- c(map, extra)
     }
 
-    ## Create internal variable name
-    var <- tempvar(value=value, envir=x, inherits=FALSE)
-    map[i] <- var
+    ## Create internal variable
+    map[i] <- new_variable(x, value=value)
 
     ## Update map
     map(x) <- map

R/utils.R

@@ -1,33 +1,3 @@
-## From R.utils 2.0.2 (2015-05-23)
-tempvar <- function(prefix="var", value, envir=parent.frame(), inherits=FALSE) {
-  maxTries <- 1e6
-  maxInt <- .Machine$integer.max
-
-  ii <- 0L
-  while (ii < maxTries) {
-    # Generate random variable name
-    idx <- sample.int(maxInt, size=1L)
-    name <- sprintf("%s%d", prefix, idx)
-
-    # Is it available?
-    if (!exists(name, envir=envir, inherits=inherits)) {
-      # Assign a value?
-      if (!missing(value)) {
-        assign(name, value, envir=envir, inherits=inherits)
-      }
-      return(name)
-    }
-
-    # Next try
-    ii <- ii + 1L
-  }
-
-  # Failed to find a unique temporary variable name
-  stop(sprintf("Failed to generate a unique non-existing temporary variable with prefix '%s'", prefix))
-} # tempvar()
-
-
-
 ## From R.utils 2.0.2 (2015-05-23)
 hpaste <- function(..., sep="", collapse=", ", lastCollapse=NULL, maxHead=if (missing(lastCollapse)) 3 else Inf, maxTail=if (is.finite(maxHead)) 1 else Inf, abbreviate="...") {
   if (is.null(lastCollapse)) lastCollapse <- collapse