From 42fe265dd2c4e6b4689ab14eaecaeebd1820da6b Mon Sep 17 00:00:00 2001
From: Kelvin Sherlock <ksherlock@gmail.com>
Date: Sun, 8 Feb 2015 14:49:08 -0500
Subject: [PATCH] Smarter handling of : after a variable.

Since :: is equivalent to .. in Unix, {$PathVariable}: would expand unexpectedly
if PathVariable had a trailing : (which it usually does) -- i.e., some:path:: == /some/path/.. = /some/.

: after a variable will be dropped if there was already a trailing :
---
 mpw/environment.rl        | 32 ++++++++++++++++++++++++++++----
 verbatim/Environment.text |  5 ++++-
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/mpw/environment.rl b/mpw/environment.rl
index 233889e..5d79bac 100644
--- a/mpw/environment.rl
+++ b/mpw/environment.rl
@@ -82,6 +82,20 @@ namespace {
 	%%{
 		machine variables;	
 
+		coalesce_colon := |*
+
+			':' {
+				if (rv.length() && rv.back() != ':')
+					rv.push_back(':');
+
+				fgoto main;
+			};
+			any {
+				fhold;
+				fgoto main;
+			};
+		*|;
+
 		main := |*
 
 			'{' [A-Za-z0-9_]+ '}' {
@@ -90,15 +104,23 @@ namespace {
 				auto iter = Environment.find(name);
 				if (iter != Environment.end())
 					rv.append(iter->second);
+
+				fgoto coalesce_colon;
 			};
 
 			# backwards compatibility.
 			'${' [A-Za-z0-9_]+ '}' {
 
-				std::string name(ts + 2, te - 1);
-				auto iter = Environment.find(name);
-				if (iter != Environment.end())
-					rv.append(iter->second);
+				if (pathname) {
+					rv.append(ts, te);
+				} else {
+					std::string name(ts + 2, te - 1);
+					auto iter = Environment.find(name);
+					if (iter != Environment.end())
+						rv.append(iter->second);
+
+					fgoto coalesce_colon;
+				}
 			};
 
 			# backwards compatibility.
@@ -112,6 +134,8 @@ namespace {
 					auto iter = Environment.find(name);
 					if (iter != Environment.end())
 						rv.append(iter->second);
+
+					fgoto coalesce_colon;
 				}
 			};
 
diff --git a/verbatim/Environment.text b/verbatim/Environment.text
index 1c387ee..c17a3d9 100644
--- a/verbatim/Environment.text
+++ b/verbatim/Environment.text
@@ -4,7 +4,10 @@
 # $MPW uses MacOS : paths.
 #
 # $MPW includes the trailing ':'.
-#Be mindful of this since '::' is equivalent to '..' in Unix.
+# Since '::' is equivalent to '..' in Unix,
+# A ':'' after a variable (eg, ${MPW}:)
+# will be dropped if it's duplicative.
+#
 #
 # = assigns (replacing any existing value)
 # ?= will not replace an existing value.