Refactor en route to #5027 -- remove usestring parameter from lookupvar

The usestring parameter to lookupvar was objectionable for several reasons;
first, it performed a function orthogonal to the main purpose of the method,
second its default was the least common value, and third it was causing other
code to work for reasons that were not obvious (extlookup).

This refactor breaks the value-transforming function out into a seperate
method which allows the user to specify the value to be used in lieu of :undef
and removes the parameter.  The function, Scope#undef_as(default,exp) is
written so that it can be used in user code (templates, functions, etc.) if
needed.

This refactor will introduce a user-visible behaviour change in the case where
users were counting on lookupvar to return "" for undefined variables.  The
best solution is to have them use undef_as, replacing:

    lookupvar('myvar')

with

    undef_as('',lookupvar('myvar'))

(with the option to specify another default value if desired).  If this is too
objectionable, we could rename the existing lookupvar as raw_lookupvar and
define

    def lookupvar(v)
      undef_as('',raw_lookupvar(v))
    end

to restore the present behaviour.

2 files changed, 10 insertions, 23 deletions

diff --git a/test/language/functions.rb b/test/language/functions.rb
index e882b68f3..84b1b3861 100755
--- a/test/language/functions.rb
+++ b/test/language/functions.rb
@@ -382,17 +382,15 @@ class TestLangFunctions < Test::Unit::TestCase
     }.each do |string, value|
       scope = mkscope
       scope.setvar("yayness", string)
-      assert_equal(string, scope.lookupvar("yayness", false))
+      assert_equal(string, scope.lookupvar("yayness"))
 
       assert_nothing_raised("An empty string was not a valid variable value") do
         ast.evaluate(scope)
       end
 
-
-        assert_equal(
-          "template #{value}\n", scope.lookupvar("output"),
-
-            "#{string.inspect} did not get evaluated correctly")
+      assert_equal(
+        "template #{value}\n", scope.lookupvar("output"),
+        "#{string.inspect} did not get evaluated correctly")
     end
   end
 
diff --git a/test/language/scope.rb b/test/language/scope.rb
index c4154dc27..ccc359651 100755
--- a/test/language/scope.rb
+++ b/test/language/scope.rb
@@ -42,22 +42,22 @@ class TestScope < Test::Unit::TestCase
     # Set a variable in the top and make sure all three can get it
     topscope.setvar("first", "topval")
     scopes.each do |name, scope|
-      assert_equal("topval", scope.lookupvar("first", false), "Could not find var in #{name}")
+      assert_equal("topval", scope.lookupvar("first"), "Could not find var in #{name}")
     end
 
     # Now set a var in the midscope and make sure the mid and bottom can see it but not the top
     midscope.setvar("second", "midval")
-    assert_equal(:undefined, scopes[:top].lookupvar("second", false), "Found child var in top scope")
+    assert_equal(:undefined, scopes[:top].lookupvar("second"), "Found child var in top scope")
     [:mid, :bot].each do |name|
-      assert_equal("midval", scopes[name].lookupvar("second", false), "Could not find var in #{name}")
+      assert_equal("midval", scopes[name].lookupvar("second"), "Could not find var in #{name}")
     end
 
     # And set something in the bottom, and make sure we only find it there.
     botscope.setvar("third", "botval")
     [:top, :mid].each do |name|
-      assert_equal(:undefined, scopes[name].lookupvar("third", false), "Found child var in top scope")
+      assert_equal(:undefined, scopes[name].lookupvar("third"), "Found child var in top scope")
     end
-    assert_equal("botval", scopes[:bot].lookupvar("third", false), "Could not find var in bottom scope")
+    assert_equal("botval", scopes[:bot].lookupvar("third"), "Could not find var in bottom scope")
 
 
     # Test that the scopes convert to hash structures correctly.
@@ -260,18 +260,7 @@ Host <<||>>"
     scope = mkscope
 
     scope.setvar("testing", :undef)
-
-
-      assert_equal(
-        :undef, scope.lookupvar("testing", false),
-
-      "undef was not returned as :undef when not string")
-
-
-        assert_equal(
-          "", scope.lookupvar("testing", true),
-
-      "undef was not returned as '' when string")
+    assert_equal(:undef, scope.lookupvar("testing"), "undef was not returned as :undef")
   end
 end