Reimplement sort / reverse / join function to format language, simplify text annotation variables, add tests

Previously, sort, reverse list, and join functionality was implemented
as special cases in Bonsai itself. Given that it has usecases
(especially in material lists, but any sort of list applies) I've moved
this function into the IOS formatting language.

The IOS formatting language previously wasn't capable of this, but the
awesome addition by @falken10vdl made the formatting language accept
queries inline, so that means it can handle lists. I also added tests
for all the new functions and expression syntax (+-*/ operators).

I simplified the code that gets the evaluated text literal - previously
it seems to call format() multiple times.

src/ifcopenshell-python/test/util/test_selector.py

@@ -35,7 +35,7 @@ import ifcopenshell.util.selector as subject
 import test.bootstrap
 
 
-class TestFormat:
+class TestFormat(test.bootstrap.IFC4):
     def test_no_formatting(self):
         assert subject.format("123") == "123"
         assert subject.format('"123"') == "123"
@@ -78,6 +78,38 @@ class TestFormat:
         assert subject.format('imperial_length(3.0, 4, "foot", "foot", false)') == "3' - 0\""
         assert subject.format('imperial_length(3.0, 4, "foot", "foot", False)') == "3' - 0\""
 
+    def test_variable_formatting(self):
+        assert subject.format('{{undefined}}') is None
+        assert subject.format('upper({{undefined}})') == "NONE"
+        assert subject.format('int({{undefined}})') == "0"
+        element = ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcWall")
+        assert subject.format('{{undefined}}', element) is None
+        assert subject.format('{{class}}', element) == "IfcWall"
+        assert subject.format('{{ class }}', element) == "IfcWall"
+        assert subject.format('upper({{ class }})', element) == "IFCWALL"
+
+    def test_list_formatting(self):
+        element = ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcWall")
+        material = ifcopenshell.api.material.add_material(self.file, name="CON01")
+        material2 = ifcopenshell.api.material.add_material(self.file, name="CON03")
+        material3 = ifcopenshell.api.material.add_material(self.file, name="CON02")
+        material_set = ifcopenshell.api.material.add_material_set(self.file, set_type="IfcMaterialLayerSet")
+        layer = ifcopenshell.api.material.add_layer(self.file, layer_set=material_set, material=material)
+        layer = ifcopenshell.api.material.add_layer(self.file, layer_set=material_set, material=material2)
+        layer = ifcopenshell.api.material.add_layer(self.file, layer_set=material_set, material=material3)
+        ifcopenshell.api.material.assign_material(self.file, products=[element], material=material_set)
+        assert subject.format('{{materials.Name}}', element) == "CON01, CON03, CON02"
+        assert subject.format('sort({{materials.Name}})', element) == "CON01, CON02, CON03"
+        assert subject.format('reverse({{materials.Name}})', element) == "CON02, CON03, CON01"
+        assert subject.format('join("-", {{materials.Name}})', element) == "CON01-CON03-CON02"
+
+    def test_expressions(self):
+        assert subject.format('2+3') == "5"
+        assert subject.format('-2+3') == "1"
+        assert subject.format('2-3') == "-1"
+        assert subject.format('3*2') == "6"
+        assert subject.format('3/2') == "1.5"
+
 
 class TestGetElementValue(test.bootstrap.IFC4):
     def test_selecting_an_elements_class_or_id_using_a_query(self):