when testing if an identifier refers to a calculated aesthetic, check the whole identifier, not a substring

also, define the regex that is used for matching only once, in a hidden global variable

fixes #834

Conflicts:
	R/layer.r

Resolved by combining.

Author: Kirill Müller

NEWS

@@ -7,6 +7,9 @@ ggplot2 0.9.3.1.99
 * `ggpcp()`, `ggfluctuation()`, `ggmissing()`, `ggstructure()`, and
   `ggorder()` are now defunct and have been removed.
 
+* `aes()` no more treats variables like `a..x..b as a calculated aesthetic.
+  (@krlmlr, #834.)
+
 
 ggplot2 0.9.3.1
 ----------------------------------------------------------------

R/labels.r

@@ -65,7 +65,7 @@ ggtitle <- function(label) {
 # Convert aesthetic mapping into text labels
 make_labels <- function(mapping) {
   remove_dots <- function(x) {
-    gsub("\\.\\.([a-zA-z._]+)\\.\\.", "\\1", x)
+    gsub(.calculated_aes_regex, "\\1", x)
   }
 
   lapply(mapping, function(x) remove_dots(deparse(x)))

R/layer.r

@@ -258,17 +258,19 @@ Layer <- proto(expr = {
 #' @export
 layer <- Layer$new
 
+# Regex to determine if an identifier refers to a calculated aesthetic
+.calculated_aes_regex <- "^\\.\\.([a-zA-z._]+)\\.\\.$"
+
 # Determine if aesthetic is calculated
 is_calculated_aes <- function(aesthetics) {
-  match <- "\\.\\.([a-zA-z._]+)\\.\\."
   stats <- rep(FALSE, length(aesthetics))
-  grepl(match, sapply(aesthetics, deparse))
+  grepl(.calculated_aes_regex, sapply(aesthetics, deparse))
 }
 
 # Strip dots from expressions
 strip_dots <- function(aesthetics) {
-  match <- "\\.\\.([a-zA-z._]+)\\.\\."
   strings <- lapply(aesthetics, deparse)
-  strings <- lapply(strings, gsub, pattern = match, replacement = "\\1")
+  strings <- lapply(strings, gsub, pattern = .calculated_aes_regex,
+                    replacement = "\\1")
   lapply(strings, function(x) parse(text = x)[[1]])
 }