Adds namespace fix for nested sequence and adds support for nested ty…

…pes in Sequence and Scalar ADT (#163)

* Modified generator to fix bug for nested sequence namespace
* Modified `fully_qualified_type_ref` method to return `FullyQualifiedTypeReference`
Previously this returned `Option<FullyQualifiedTypeReference>`
* Modified templates for nested types in sequence
* Adds tests for nested enums
* Adds changes for using enum in namespace
* Adds `NamespaceNode` for `FullyQualifiedName`

Cargo.toml

@@ -36,6 +36,7 @@ thiserror = "1.0.50"
 zstd = "0.13.0"
 termcolor = "1.4.1"
 derive_builder = "0.20.0"
+itertools = "0.13.0"
 
 [target.'cfg(not(target_os = "windows"))'.dependencies]
 pager = "0.16.1"

code-gen-projects/input/bad/sequence_with_enum_element/invalid_value.ion

@@ -0,0 +1 @@
+[foobar] // expected values are either foo , bar or baz, found foobar.

code-gen-projects/input/good/sequence_with_enum_element/valid_value.ion

@@ -0,0 +1 @@
+[foo, bar, baz]

code-gen-projects/java/code-gen-demo/src/test/java/org/example/CodeGenTest.java

@@ -137,6 +137,12 @@ void roundtripBadTestForEnumType() throws IOException {
         runRoundtripBadTest("/bad/enum_type", EnumType::readFrom);
     }
 
+
+    @Test
+    void roundtripBadTestForSequenceWithEnumElement() throws IOException {
+        runRoundtripBadTest("/bad/sequence_with_enum_element", SequenceWithEnumElement::readFrom);
+    }
+
     private <T> void runRoundtripBadTest(String path, ReaderFunction<T> readerFunction) throws IOException {
         File dir = new File(System.getenv("ION_INPUT") + path);
         String[] fileNames = dir.list();
@@ -182,6 +188,11 @@ void roundtripGoodTestForEnumType() throws IOException {
         runRoundtripGoodTest("/good/enum_type", EnumType::readFrom, (item, writer) -> item.writeTo(writer));
     }
 
+    @Test
+    void roundtripGoodTestForSequenceWithEnumElement() throws IOException {
+        runRoundtripGoodTest("/good/sequence_with_enum_element", SequenceWithEnumElement::readFrom, (item, writer) -> item.writeTo(writer));
+    }
+
     private <T> void runRoundtripGoodTest(String path, ReaderFunction<T> readerFunction, WriterFunction<T> writerFunction) throws IOException {
         File dir = new File(System.getenv("ION_INPUT") + path);
         String[] fileNames = dir.list();

code-gen-projects/schema/sequence_with_enum_element.isl

@@ -0,0 +1,5 @@
+type::{
+    name: sequence_with_enum_element,
+    type: list,
+    element: { valid_values: [foo, bar, baz] }
+}