Struct CodegenBuilder

pub struct CodegenBuilder { /* private fields */ }

Generate a type safe interface to use with subxt. The options exposed here are similar to those exposed via the #[subxt] macro or via the subxt codegen CLI command. Both use this under the hood.

Example

Generating an interface using all of the defaults:

use codec::Decode;
use subxt_codegen::{ Metadata, CodegenBuilder };

// Get hold of and decode some metadata:
let encoded = std::fs::read("../artifacts/polkadot_metadata_full.scale").unwrap();
let metadata = Metadata::decode(&mut &*encoded).unwrap();

// Generate a TokenStream representing the code for the interface.
// This can be converted to a string, displayed as-is or output from a macro.
let token_stream = CodegenBuilder::new().generate(metadata);

Implementations

impl CodegenBuilder

pub fn new() -> Self

Construct a builder to configure and generate a type-safe interface for Subxt.

pub fn disable_default_derives(&mut self)

Disable the default derives that are applied to all types.

Warning

This is not recommended, and is highly likely to break some part of the generated interface. Expect compile errors.

pub fn disable_default_substitutes(&mut self)

Disable the default type substitutions that are applied to the generated code.

Warning

This is not recommended, and is highly likely to break some part of the generated interface. Expect compile errors.

pub fn no_docs(&mut self)

Disable the output of doc comments associated with the generated types and methods. This can reduce the generated code size at the expense of losing documentation.

pub fn runtime_types_only(&mut self)

Only generate the types, and don’t generate the rest of the Subxt specific interface.

pub fn set_additional_global_derives(&mut self, derives: Vec<Path>)

Set the additional derives that will be applied to all types. By default, a set of derives required for Subxt are automatically added for all types.

Warning

Invalid derives, or derives that cannot be applied to all of the generated types (taking into account that some types are substituted for hand written ones that we cannot add extra derives for) will lead to compile errors in the generated code.

pub fn set_additional_global_attributes(&mut self, attributes: Vec<Attribute>)

Set the additional attributes that will be applied to all types. By default, a set of attributes required for Subxt are automatically added for all types.

Warning

Invalid attributes can very easily lead to compile errors in the generated code.

pub fn add_derives_for_type( &mut self, ty: TypePath, derives: impl IntoIterator<Item = Path>, recursive: bool, )

Set additional derives for a specific type at the path given.

If you want to set the additional derives on all contained types recursively as well, you can set the recursive argument to true. If you don’t do that, there might be compile errors in the generated code, if the derived trait relies on the fact that contained types also implement that trait.

pub fn add_attributes_for_type( &mut self, ty: TypePath, attributes: impl IntoIterator<Item = Attribute>, recursive: bool, )

Set additional attributes for a specific type at the path given.

Setting the recursive argument to true will additionally add the specified attributes to all contained types recursively.

pub fn set_type_substitute(&mut self, ty: Path, with: Path)

Substitute a type at the given path with some type at the second path. During codegen, we will avoid generating the type at the first path given, and instead point any references to that type to the second path given.

The substituted type will need to implement the relevant traits to be compatible with the original, and it will need to SCALE encode and SCALE decode in a compatible way.

pub fn set_target_module(&mut self, item_mod: ItemMod)

By default, all of the code is generated inside a module pub mod api {}. We decorate this module with a few attributes to reduce compile warnings and things. You can provide a target module here, allowing you to add additional attributes or inner code items (with the warning that duplicate identifiers will lead to compile errors).

pub fn set_subxt_crate_path(&mut self, crate_path: Path)

Set the path to the subxt crate. By default, we expect it to be at ::subxt::ext::subxt_core.

Panics

Panics if the path provided is not an absolute path.

pub fn generate(self, metadata: Metadata) -> Result<TokenStream2, CodegenError>

Generate an interface, assuming that the default path to the subxt crate is ::subxt::ext::subxt_core. If the subxt crate is not available as a top level dependency, use generate and provide a valid path to the `subxt¦ crate.

Trait Implementations

impl Default for CodegenBuilder

fn default() -> Self

Returns the “default value” for a type.