added expand_bash_syntax_vars function

git-svn-id: svn://svn.alpinelinux.org/acf/core/trunk@1473 ab2d0c66-481e-0410-8bed-d214d4d58bed

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/format.lua b/lib/format.lua
index 60fda82..5b3e220 100644
--- a/lib/format.lua
+++ b/lib/format.lua
@@ -159,3 +159,27 @@ function md5sum_string ( str)
 	f:close()
 	return checksum[1]
 end
+
+
+-- Takes a str and expands any ${...} constructs with the Lua variable
+-- ex: a="foo"; print(expand_bash_syntax_vars("a=${a}) - > "a=foo"
+
+expand_bash_syntax_vars = function ( str )
+
+  local deref = function ( f)
+    local v = _G
+    for w in string.gfind(f, "[%w_]+") do
+      v = v[w]
+    end
+  return v
+  end
+
+  for w in string.gmatch (str, "${[^}]*}" ) do
+        local rvar = string.sub(w,3,-2)
+        local rval = ( deref(rvar) or "nil" )
+        str = string.gsub (str, w, rval)
+  end
+ return (str)
+end
+
+