Importing types from cip 57 files

[nicolasLuduena]

This pull request introduces support for imports in the tx3-lang language, allowing programs to reference external files such as JSON blueprints. It adds a new cip-57 crate for Cardano CIP-57 compatibility, updates parsing and AST structures to handle imports, and demonstrates the feature with a new example. The most important changes are grouped below.

Import system integration

• Added ImportDef struct to the AST and updated Program to support a list of imports. Parsing logic and grammar were extended to recognize and process import statements.

CIP-57 blueprint support

• Added the new cip-57 crate, including its Cargo.toml and a comprehensive lib.rs defining blueprint structures for JSON parsing and serialization according to CIP-57.
• Registered the cip-57 crate as a workspace member and as a dependency in tx3-lang.

Example and test coverage

• Added examples/imported_datum.tx3 to demonstrate how an external JSON blueprint can be imported and used in a transaction definition.
• Expanded parsing tests to include import handling and updated test fixtures for the new import feature.

These changes collectively enable the tx3-lang language to import and reference external data and schemas, improving extensibility and interoperability with Cardano standards.

[Copilot]

Pull request overview

This PR adds an import system to tx3-lang and introduces a new cip-57 crate to parse Cardano CIP-57 Plutus blueprints, enabling external JSON-defined types to be referenced from Tx3 programs.

Changes:

• Extended the Tx3 grammar/AST/parser to support import "path" as alias;.
• Added an import resolver that loads CIP-57 JSON blueprints and converts definitions into Tx3 TypeDefs.
• Added a new cip-57 crate plus an example Tx3 program and snapshot fixture demonstrating the feature.

Reviewed changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
examples/imported_datum.tx3	Demonstrates importing a CIP-57 blueprint and constructing imported types.
examples/imported_datum.ast	New AST snapshot fixture for the example program.
crates/tx3-lang/src/tx3.pest	Adds import_def grammar and allows imports at program top-level.
crates/tx3-lang/src/parsing.rs	Parses import statements into the AST and updates tests/fixtures.
crates/tx3-lang/src/lib.rs	Exposes the new importing module.
crates/tx3-lang/src/importing.rs	Implements CIP-57 JSON loading + mapping definitions to Tx3 types, with tests.
crates/tx3-lang/src/facade.rs	Resolves imports during Workspace::parse() when a filesystem root is available.
crates/tx3-lang/src/cardano.rs	Minor test import cleanup.
crates/tx3-lang/src/ast.rs	Adds Program.imports and new ImportDef AST node.
crates/tx3-lang/Cargo.toml	Adds cip-57 and serde_json dependencies.
crates/cip-57/src/lib.rs	Implements CIP-57 blueprint structures for serde (de)serialization.
crates/cip-57/examples/plutus.json	Adds a sample Plutus blueprint JSON used by examples/tests.
crates/cip-57/Cargo.toml	New crate manifest for cip-57.
Cargo.toml	Registers crates/cip-57 as a workspace member.
Cargo.lock	Adds cip-57 to the lockfile and updates dependency graph.

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[Copilot]

FsLoader::load_source allows absolute paths (where PathBuf::join ignores root) and .. path traversal, so an import can read files outside the intended project root. Consider rejecting absolute paths and normalizing/canonicalizing the joined path, then enforcing it stays under root before reading.

[Copilot]

Definitions without anyOf (and without a primitive/list/map dataType) are currently skipped unless the key is exactly Data. However resolve_ref_to_type will still return Type::Custom for these refs (e.g. cardano/transaction/Redeemer in the included example blueprint), which can lead to unresolved types during analysis. Consider importing such definitions as an opaque placeholder (e.g. a single empty Default case) or mapping them to an existing "any data" type, instead of skipping them here.

Suggested change

	if key == "Data" {
	return Ok(Some(TypeDef {
	name: Identifier::new(import_type_name(key, alias)),
	cases: vec![VariantCase {
	name: Identifier::new("Default"),
	fields: vec![],
	span: Span::DUMMY,
	}],
	span: Span::DUMMY,
	}));
	}
	return Ok(None);
	return Ok(Some(TypeDef {
	name: Identifier::new(import_type_name(key, alias)),
	cases: vec![VariantCase {
	name: Identifier::new("Default"),
	fields: vec![],
	span: Span::DUMMY,
	}],
	span: Span::DUMMY,
	}));