Adds support for imports in code generation (#169)

* Modifies `generate_code_for_authorities` to traverse through all
subdirectories of a schema authority to generate code
* Modifies `generate` to generate code for header and inline imports
* Adds a change for scalar template
* Adds tests for inline and header imports
* Remove `--schema` option

code-gen-projects/input/bad/sequence_with_import/mismatched_sequence_element_type.ion

@@ -0,0 +1 @@
+[ mango ] // expected apple, banana or strawberry, found mango

code-gen-projects/input/bad/sequence_with_import/mismatched_sequence_type.ion

@@ -0,0 +1 @@
+(apple banana) // expected list, found sexp

code-gen-projects/input/bad/struct_with_inline_import/mismatched_import_type.ion

@@ -0,0 +1,5 @@
+// simple struct with type mismatched import field
+{
+ A: "hello",
+ B: false, // expected field type symbol
+}

code-gen-projects/input/good/sequence_with_import/empty_sequence.ion

@@ -0,0 +1 @@
+[]

code-gen-projects/input/good/sequence_with_import/valid_elements.ion

@@ -0,0 +1 @@
+[ apple, strawberry ]

code-gen-projects/input/good/struct_with_inline_import/valid_fields.ion

@@ -0,0 +1,5 @@
+// simple struct with all valid fields
+{
+ A: "hello",
+ B: apple,
+}

code-gen-projects/input/good/struct_with_inline_import/valid_optional_fields.ion

@@ -0,0 +1,5 @@
+// simple struct with all valid fields
+{
+ A: "hello",
+ // B: apple, // since `B` is an optional field, this is a valid struct
+}

code-gen-projects/input/good/struct_with_inline_import/valid_unordered_fields.ion

@@ -0,0 +1,5 @@
+// struct with unordered fields
+{
+ B: banana,
+ A: "hello",
+}

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

@@ -150,12 +150,21 @@ void roundtripBadTestForEnumType() throws IOException {
         runRoundtripBadTest("/bad/enum_type", EnumType::readFrom);
     }
 
-
     @Test
     void roundtripBadTestForSequenceWithEnumElement() throws IOException {
         runRoundtripBadTest("/bad/sequence_with_enum_element", SequenceWithEnumElement::readFrom);
     }
 
+    @Test
+    void roundtripBadTestForSequenceWithImport() throws IOException {
+        runRoundtripBadTest("/bad/sequence_with_import", SequenceWithImport::readFrom);
+    }
+
+    @Test
+    void roundtripBadTestForStructWithInlineImport() throws IOException {
+        runRoundtripBadTest("/bad/struct_with_inline_import", StructWithInlineImport::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();
@@ -206,6 +215,16 @@ void roundtripGoodTestForSequenceWithEnumElement() throws IOException {
         runRoundtripGoodTest("/good/sequence_with_enum_element", SequenceWithEnumElement::readFrom, (item, writer) -> item.writeTo(writer));
     }
 
+    @Test
+    void roundtripGoodTestForSequenceWithImport() throws IOException {
+        runRoundtripGoodTest("/good/sequence_with_import", SequenceWithImport::readFrom, (item, writer) -> item.writeTo(writer));
+    }
+
+    @Test
+    void roundtripGoodTestForStructWithInlineImport() throws IOException {
+        runRoundtripGoodTest("/good/struct_with_inline_import", StructWithInlineImport::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_import.isl

@@ -0,0 +1,13 @@
+schema_header::{
+    imports: [
+        { id: "utils/fruits.isl", type: fruits }
+    ]
+}
+
+type::{
+    name: sequence_with_import,
+    type: list,
+    element: fruits
+}
+
+schema_footer::{}

code-gen-projects/schema/struct_with_inline_import.isl

@@ -0,0 +1,8 @@
+type::{
+ name: struct_with_inline_import,
+ type: struct,
+ fields: {
+    A: string,
+    B: { id: "utils/fruits.isl", type: fruits }
+ }
+}

code-gen-projects/schema/utils/fruits.isl

@@ -0,0 +1,4 @@
+type::{
+   name: fruits,
+   valid_values: [apple, banana, strawberry]
+}

src/bin/ion/commands/generate/generator.rs

@@ -277,30 +277,51 @@ impl<'a, L: Language + 'static> CodeGenerator<'a, L> {
         schema_system: &mut SchemaSystem,
     ) -> CodeGenResult<()> {
         for authority in authorities {
-            // Sort the directory paths to ensure nested type names are always ordered based
-            // on directory path. (nested type name uses a counter in its name to represent that type)
-            let mut paths = fs::read_dir(authority)?.collect::<Result<Vec<_>, _>>()?;
-            paths.sort_by_key(|dir| dir.path());
-            for schema_file in paths {
-                let schema_file_path = schema_file.path();
-                let schema_id = schema_file_path.file_name().unwrap().to_str().unwrap();
-
-                let schema = schema_system.load_isl_schema(schema_id).unwrap();
-
-                self.generate(schema)?;
-            }
+            self.generate_code_for_directory(authority, None, schema_system)?;
         }
         Ok(())
     }
 
-    /// Generates code for given Ion Schema
-    pub fn generate_code_for_schema(
+    /// Helper method to generate code for all schema files in a directory
+    /// `relative_path` is used to provide a relative path to the authority for a nested directory
+    pub fn generate_code_for_directory<P: AsRef<Path>>(
         &mut self,
+        directory: P,
+        relative_path: Option<&str>,
         schema_system: &mut SchemaSystem,
-        schema_id: &str,
     ) -> CodeGenResult<()> {
-        let schema = schema_system.load_isl_schema(schema_id).unwrap();
-        self.generate(schema)
+        let paths = fs::read_dir(&directory)?.collect::<Result<Vec<_>, _>>()?;
+        for schema_file in paths {
+            let schema_file_path = schema_file.path();
+
+            // if this is a nested directory then load schema files from it
+            if schema_file_path.is_dir() {
+                self.generate_code_for_directory(
+                    &schema_file_path,
+                    Some(
+                        schema_file_path
+                            .strip_prefix(&directory)
+                            .unwrap()
+                            .to_str()
+                            .unwrap(),
+                    ),
+                    schema_system,
+                )?;
+            } else {
+                let schema = if let Some(path) = relative_path {
+                    let relative_path_with_schema_id = Path::new(path)
+                        .join(schema_file_path.file_name().unwrap().to_str().unwrap());
+                    schema_system
+                        .load_isl_schema(relative_path_with_schema_id.as_path().to_str().unwrap())
+                } else {
+                    schema_system
+                        .load_isl_schema(schema_file_path.file_name().unwrap().to_str().unwrap())
+                }?;
+                self.generate(schema)?;
+            }
+        }
+
+        Ok(())
     }
 
     fn generate(&mut self, schema: IslSchema) -> CodeGenResult<()> {
@@ -328,7 +349,6 @@ impl<'a, L: Language + 'static> CodeGenerator<'a, L> {
             let isl_type_name = isl_type.name().unwrap().to_string();
             self.generate_abstract_data_type(&isl_type_name, isl_type)?;
         }
-
         Ok(())
     }
 
@@ -597,24 +617,10 @@ impl<'a, L: Language + 'static> CodeGenerator<'a, L> {
         type_name_suggestion: Option<&str>,
     ) -> CodeGenResult<Option<FullyQualifiedTypeReference>> {
         Ok(match isl_type_ref {
-            IslTypeRef::Named(name, _) => {
-                let schema_type: IonSchemaType = name.into();
-                L::target_type(&schema_type)
-                    .as_ref()
-                    .map(|type_name| FullyQualifiedTypeReference {
-                        type_name: vec![NamespaceNode::Type(type_name.to_string())],
-                        parameters: vec![],
-                    })
-                    .map(|t| {
-                        if field_presence == FieldPresence::Optional {
-                            L::target_type_as_optional(t)
-                        } else {
-                            t
-                        }
-                    })
-            }
-            IslTypeRef::TypeImport(_, _) => {
-                unimplemented!("Imports in schema are not supported yet!");
+            IslTypeRef::Named(name, _) => Self::target_type_for(field_presence, name),
+            IslTypeRef::TypeImport(isl_import_type, _) => {
+                let name = isl_import_type.type_name();
+                Self::target_type_for(field_presence, name)
             }
             IslTypeRef::Anonymous(type_def, _) => {
                 let name = type_name_suggestion.map(|t| t.to_string()).ok_or(
@@ -637,6 +643,27 @@ impl<'a, L: Language + 'static> CodeGenerator<'a, L> {
         })
     }
 
+    /// Returns the target type based on given ISL type name and field presence
+    fn target_type_for(
+        field_presence: FieldPresence,
+        name: &String,
+    ) -> Option<FullyQualifiedTypeReference> {
+        let schema_type: IonSchemaType = name.into();
+        L::target_type(&schema_type)
+            .as_ref()
+            .map(|type_name| FullyQualifiedTypeReference {
+                type_name: vec![NamespaceNode::Type(type_name.to_string())],
+                parameters: vec![],
+            })
+            .map(|t| {
+                if field_presence == FieldPresence::Optional {
+                    L::target_type_as_optional(t)
+                } else {
+                    t
+                }
+            })
+    }
+
     /// Returns error if duplicate constraints are present based `found_constraint` flag
     fn handle_duplicate_constraint(
         &mut self,

src/bin/ion/commands/generate/mod.rs

@@ -45,12 +45,6 @@ impl IonCliCommand for GenerateCommand {
                     .short('o')
                     .help("Output directory [default: current directory]"),
             )
-            .arg(
-                Arg::new("schema")
-                    .long("schema")
-                    .short('s')
-                    .help("Schema file name or schema id"),
-            )
             // `--namespace` is required when Java language is specified for code generation
             .arg(
                 Arg::new("namespace")
@@ -118,49 +112,26 @@ impl IonCliCommand for GenerateCommand {
 
         println!("Started generating code...");
 
-        // Extract schema file provided by user
-        match args.get_one::<String>("schema") {
-            None => {
-                // generate code based on schema and programming language
-                match language {
-                    "java" => {
-                        Self::print_java_code_gen_warnings();
-                        CodeGenerator::<JavaLanguage>::new(output, namespace.unwrap().split('.').map(|s| NamespaceNode::Package(s.to_string())).collect())
-                            .generate_code_for_authorities(&authorities, &mut schema_system)?
-                    },
-                    "rust" => {
-                        Self::print_rust_code_gen_warnings();
-                        CodeGenerator::<RustLanguage>::new(output)
-                            .generate_code_for_authorities(&authorities, &mut schema_system)?
-                    }
-                    _ => bail!(
-                        "Programming language '{}' is not yet supported. Currently supported targets: 'java', 'rust'",
-                        language
-                    )
-                }
-            }
-            Some(schema_id) => {
-                // generate code based on schema and programming language
-                match language {
-                    "java" =>  {
-                        Self::print_java_code_gen_warnings();
-                        CodeGenerator::<JavaLanguage>::new(output, namespace.unwrap().split('.').map(|s| NamespaceNode::Package(s.to_string())).collect()).generate_code_for_schema(&mut schema_system, schema_id)?
-                    },
-                    "rust" => {
-                        Self::print_rust_code_gen_warnings();
-                        CodeGenerator::<RustLanguage>::new(output)
-                            .generate_code_for_authorities(&authorities, &mut schema_system)?
-                    }
-                    _ => bail!(
-                        "Programming language '{}' is not yet supported. Currently supported targets: 'java', 'rust'",
-                        language
-                    )
-                }
+        // generate code based on schema and programming language
+        match language {
+            "java" => {
+                Self::print_java_code_gen_warnings();
+                CodeGenerator::<JavaLanguage>::new(output, namespace.unwrap().split('.').map(|s| NamespaceNode::Package(s.to_string())).collect())
+                    .generate_code_for_authorities(&authorities, &mut schema_system)?
+            },
+            "rust" => {
+                Self::print_rust_code_gen_warnings();
+                CodeGenerator::<RustLanguage>::new(output)
+                    .generate_code_for_authorities(&authorities, &mut schema_system)?
             }
+            _ => bail!(
+                "Programming language '{}' is not yet supported. Currently supported targets: 'java', 'rust'",
+                language
+            )
         }
 
         println!("Code generation complete successfully!");
-        println!("Path to generated code: {}", output.display());
+        println!("All the schema files in authority(s) are generated into a flattened namespace, path to generated code: {}", output.display());
         Ok(())
     }
 }

src/bin/ion/commands/generate/templates/java/scalar.templ

@@ -69,7 +69,7 @@ class {{ model.name }} {
     public void writeTo(IonWriter writer) throws IOException {
         {# Writes `Value` class with a single field `value` as an Ion value #}
         {% if base_type | is_built_in_type == false  %}
-            this.value.writeTo(writer)?;
+            this.value.writeTo(writer);
         {% else %}
             writer.write{{ base_type | replace(from="double", to="float") | replace(from="boolean", to="bool") | upper_camel }}(this.value);
         {% endif %}

tests/cli.rs

@@ -266,8 +266,6 @@ mod code_gen_tests {
         cmd.args([
             "-X",
             "generate",
-            "--schema",
-            "test_schema.isl",
             "--output",
             temp_dir.path().to_str().unwrap(),
             "--language",