Support CSS calc().

5 files changed, 41 insertions, 30 deletions

diff --git a/scss/grammar/expression.g b/scss/grammar/expression.g
index 760358c..026f07a 100644
--- a/scss/grammar/expression.g
+++ b/scss/grammar/expression.g
@@ -71,6 +71,11 @@ parser SassExpression:
     token KWVAR: "\$[-a-zA-Z0-9_]+(?=\s*:)"
     token SLURPYVAR: "\$[-a-zA-Z0-9_]+(?=[.][.][.])"
     token VAR: "\$[-a-zA-Z0-9_]+"
+    # Cheating, to make sure these only match function names.
+    # The last of these is the IE filter nonsense
+    token LITERAL_FUNCTION: "(calc|expression|progid:[\w.]+)(?=[(])"
+    token URL_FUNCTION: "url(?=[(])"
+    # This must come AFTER the above two
     token FNCT: "[-a-zA-Z_][-a-zA-Z0-9_]*(?=\()"
     # TODO Ruby is a bit more flexible here, for example allowing 1#{2}px
     token BAREWORD: "[-a-zA-Z_][-a-zA-Z0-9_]*"
@@ -213,10 +218,10 @@ parser SassExpression:
         # different tokens so yapps can't tell, and it resolves the conflict by
         # picking the first one.
         # TODO Ruby sass somehow allows a full expression in here too
-        | "url" LPAR interpolated_url RPAR
+        | URL_FUNCTION LPAR interpolated_url RPAR
             {{ return interpolated_url }}
-        | "expression" LPAR interpolated_function RPAR
-            {{ return Interpolation.maybe(interpolated_function, type=Function, function_name='expression') }}
+        | LITERAL_FUNCTION LPAR interpolated_function RPAR
+            {{ return Interpolation.maybe(interpolated_function, type=Function, function_name=LITERAL_FUNCTION) }}
         | FNCT LPAR argspec RPAR    {{ return CallOp(FNCT, argspec) }}
         | BANG_IMPORTANT            {{ return Literal(String(BANG_IMPORTANT, quotes=None)) }}
         | interpolated_bareword     {{ return Interpolation.maybe(interpolated_bareword) }}
diff --git a/scss/grammar/expression.py b/scss/grammar/expression.py
index 8edb962..397fa4c 100644
--- a/scss/grammar/expression.py
+++ b/scss/grammar/expression.py
@@ -40,8 +40,6 @@ from scss.grammar import Scanner
 class SassExpressionScanner(Scanner):
     patterns = None
     _patterns = [
-        ('"expression"', 'expression'),
-        ('"url"', 'url'),
         ('":"', ':'),
         ('","', ','),
         ('[ \r\t\n]+', '[ \r\t\n]+'),
@@ -76,6 +74,8 @@ class SassExpressionScanner(Scanner):
         ('KWVAR', '\\$[-a-zA-Z0-9_]+(?=\\s*:)'),
         ('SLURPYVAR', '\\$[-a-zA-Z0-9_]+(?=[.][.][.])'),
         ('VAR', '\\$[-a-zA-Z0-9_]+'),
+        ('LITERAL_FUNCTION', '(calc|expression|progid:[\\w.]+)(?=[(])'),
+        ('URL_FUNCTION', 'url(?=[(])'),
         ('FNCT', '[-a-zA-Z_][-a-zA-Z0-9_]*(?=\\()'),
         ('BAREWORD', '[-a-zA-Z_][-a-zA-Z0-9_]*'),
         ('BANG_IMPORTANT', '!important'),
@@ -317,18 +317,18 @@ class SassExpression(Parser):
                 v = expr_map_or_list
             RPAR = self._scan('RPAR')
             return Parentheses(v)
-        elif _token_ == '"url"':
-            self._scan('"url"')
+        elif _token_ == 'URL_FUNCTION':
+            URL_FUNCTION = self._scan('URL_FUNCTION')
             LPAR = self._scan('LPAR')
             interpolated_url = self.interpolated_url()
             RPAR = self._scan('RPAR')
             return interpolated_url
-        elif _token_ == '"expression"':
-            self._scan('"expression"')
+        elif _token_ == 'LITERAL_FUNCTION':
+            LITERAL_FUNCTION = self._scan('LITERAL_FUNCTION')
             LPAR = self._scan('LPAR')
             interpolated_function = self.interpolated_function()
             RPAR = self._scan('RPAR')
-            return Interpolation.maybe(interpolated_function, type=Function, function_name='expression')
+            return Interpolation.maybe(interpolated_function, type=Function, function_name=LITERAL_FUNCTION)
         elif _token_ == 'FNCT':
             FNCT = self._scan('FNCT')
             LPAR = self._scan('LPAR')
@@ -473,42 +473,42 @@ class SassExpression(Parser):
         return Interpolation.maybe(parts)
 
     atom_chks_ = set(['COLOR', 'VAR'])
-    expr_map_or_list_rsts__ = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'INTERP_START', 'COLOR', '"expression"', 'RPAR', 'BAREWORD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
-    u_expr_chks = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'INTERP_START', 'COLOR', '"expression"', 'BAREWORD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
-    m_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'INTERP_START', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    expr_map_or_list_rsts__ = set(['LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'RPAR', 'VAR', 'NUM', 'FNCT', 'LITERAL_FUNCTION', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
+    u_expr_chks = set(['LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'VAR', 'NUM', 'FNCT', 'LITERAL_FUNCTION', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    m_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     argspec_items_rsts = set(['RPAR', 'END', '","'])
     expr_slst_chks = set(['INTERP_END', 'RPAR', 'END', '":"', '","'])
     expr_lst_rsts = set(['INTERP_END', 'END', '","'])
     expr_map_or_list_rsts = set(['RPAR', '":"', '","'])
-    argspec_item_chks = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'INTERP_START', 'COLOR', '"expression"', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    argspec_item_chks = set(['LPAR', 'DOUBLE_QUOTE', 'VAR', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
     a_expr_chks = set(['ADD', 'SUB'])
     interpolated_function_parens_rsts = set(['LPAR', 'RPAR', 'INTERP_START'])
-    expr_slst_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'END', 'INTERP_START', 'COLOR', '"expression"', 'FNCT', 'SIGN', 'VAR', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
-    interpolated_bareword_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'INTERP_START', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
-    or_expr_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'END', 'SINGLE_QUOTE', 'INTERP_START', 'COLOR', '"expression"', 'FNCT', 'SIGN', 'VAR', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'OR', '","'])
+    expr_slst_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'VAR', 'END', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'FNCT', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
+    interpolated_bareword_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', 'GT', 'END', 'SIGN', 'LITERAL_FUNCTION', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    or_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'VAR', 'END', 'SINGLE_QUOTE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'FNCT', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'OR', '","'])
     argspec_chks_ = set(['END', 'RPAR'])
     interpolated_string_single_rsts = set(['SINGLE_QUOTE', 'INTERP_START'])
-    interpolated_bareword_rsts_ = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'INTERP_START', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
-    and_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'INTERP_START', 'COLOR', '"expression"', 'NUM', '":"', 'BAREWORD', '"url"', 'END', 'SIGN', 'ADD', 'FNCT', 'VAR', 'AND', 'OR', 'NOT', 'SINGLE_QUOTE', '","'])
-    comparison_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'INTERP_START', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'ADD', 'FNCT', 'VAR', 'EQ', 'AND', 'GE', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    interpolated_bareword_rsts_ = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    and_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NUM', '":"', 'BAREWORD', 'END', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'FNCT', 'VAR', 'AND', 'OR', 'NOT', 'SINGLE_QUOTE', '","'])
+    comparison_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'ADD', 'FNCT', 'VAR', 'EQ', 'AND', 'GE', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     argspec_chks = set(['DOTDOTDOT', 'SLURPYVAR'])
-    atom_rsts_ = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'VAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'INTERP_START', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'UNITS', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    atom_rsts_ = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'VAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'UNITS', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     interpolated_string_double_rsts = set(['DOUBLE_QUOTE', 'INTERP_START'])
     expr_map_or_list_rsts_ = set(['RPAR', '","'])
-    u_expr_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'INTERP_START', 'COLOR', '"expression"', 'SIGN', 'BAREWORD', 'ADD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    u_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'LITERAL_FUNCTION', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
     atom_chks = set(['BAREWORD', 'INTERP_START'])
     interpolated_url_rsts = set(['DOUBLE_QUOTE', 'BAREURL', 'SINGLE_QUOTE'])
     comparison_chks = set(['GT', 'GE', 'NE', 'LT', 'LE', 'EQ'])
-    argspec_items_rsts_ = set(['KWVAR', 'LPAR', 'RPAR', 'BAREWORD', 'END', 'SLURPYVAR', 'INTERP_START', 'COLOR', 'DOTDOTDOT', 'DOUBLE_QUOTE', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'SINGLE_QUOTE', 'BANG_IMPORTANT', '"expression"'])
-    a_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'INTERP_START', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    argspec_items_rsts_ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'VAR', 'END', 'SLURPYVAR', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'DOTDOTDOT', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'RPAR', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    a_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     interpolated_string_rsts = set(['DOUBLE_QUOTE', 'SINGLE_QUOTE'])
     m_expr_chks = set(['MUL', 'DIV'])
     goal_interpolated_anything_rsts = set(['END', 'INTERP_START'])
     interpolated_bare_url_rsts = set(['RPAR', 'INTERP_START'])
-    argspec_items_chks = set(['KWVAR', '"url"', 'DOUBLE_QUOTE', 'BAREWORD', 'LPAR', 'COLOR', '"expression"', 'INTERP_START', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
-    argspec_rsts = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'SLURPYVAR', 'INTERP_START', 'COLOR', 'BAREWORD', 'DOTDOTDOT', 'RPAR', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'SINGLE_QUOTE', 'SIGN', '"expression"'])
-    atom_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'INTERP_START', 'COLOR', 'BAREWORD', '"expression"', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'RPAR', 'SINGLE_QUOTE'])
-    argspec_items_rsts__ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'SLURPYVAR', 'INTERP_START', 'COLOR', 'DOTDOTDOT', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'SINGLE_QUOTE', 'BANG_IMPORTANT', '"expression"'])
-    argspec_rsts_ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'INTERP_START', 'COLOR', 'BAREWORD', '"expression"', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'RPAR', 'SINGLE_QUOTE'])
+    argspec_items_chks = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'VAR', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    argspec_rsts = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'SLURPYVAR', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'DOTDOTDOT', 'RPAR', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'VAR', 'FNCT', 'NOT', 'SIGN', 'SINGLE_QUOTE'])
+    atom_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'VAR', 'FNCT', 'NOT', 'RPAR', 'SINGLE_QUOTE'])
+    argspec_items_rsts__ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'VAR', 'SLURPYVAR', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'DOTDOTDOT', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    argspec_rsts_ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'BAREWORD', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'VAR', 'FNCT', 'NOT', 'RPAR', 'SINGLE_QUOTE'])
 
 
diff --git a/scss/tests/files/general/css-calc.css b/scss/tests/files/general/css-calc.css
new file mode 100644
index 0000000..6d13266
--- /dev/null
+++ b/scss/tests/files/general/css-calc.css
@@ -0,0 +1,3 @@
+p {
+  width: calc(100% - 10px);
+}
diff --git a/scss/tests/files/general/css-calc.scss b/scss/tests/files/general/css-calc.scss
new file mode 100644
index 0000000..aba10f7
--- /dev/null
+++ b/scss/tests/files/general/css-calc.scss
@@ -0,0 +1,3 @@
+p {
+    width: calc(100% - 10px);
+}
diff --git a/scss/tests/test_expression.py b/scss/tests/test_expression.py
index 0a860cf..de39b01 100644
--- a/scss/tests/test_expression.py
+++ b/scss/tests/test_expression.py
@@ -59,7 +59,7 @@ def test_reference_operations():
     assert calc('opacify($translucent-red, 0.3)') == Color.from_rgb(1, 0, 0, 0.8)
     assert calc('transparentize($translucent-red, 0.25)') == Color.from_rgb(1, 0, 0, 0.25)
     assert calc("progid:DXImageTransform.Microsoft.gradient(enabled='false', startColorstr='#{ie-hex-str($green)}', endColorstr='#{ie-hex-str($translucent-red)}')"
-                ) == String.unquoted("progid:DXImageTransform.Microsoft.gradient(enabled='false', startColorstr='#FF00FF00', endColorstr='#80FF0000')")
+                ).render() == "progid:DXImageTransform.Microsoft.gradient(enabled='false', startColorstr='#FF00FF00', endColorstr='#80FF0000')"
 
     # String operations
     ns.set_variable('$value', Null())