ferogram-tl-gen

ferogram-tl-gen

Build-time Rust code generator for Telegram's TL schema.

Runs during cargo build via build.rs. Takes a parsed TL AST from ferogram-tl-parser and writes Rust source to $OUT_DIR. Not a runtime dependency add it to [build-dependencies], not [dependencies].

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Installation

[build-dependencies]
ferogram-tl-gen = "0.3.0"

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Usage in build.rs

use ferogram_tl_gen::{generate, Config};

fn main() {
    let out_dir = std::env::var("OUT_DIR").unwrap();

    generate(
        "tl/api.tl",
        &format!("{out_dir}/generated_api.rs"),
        Config {
            impl_debug:      true,
            impl_from_type:  true,
            impl_from_enum:  true,
            impl_serde:      false,
            name_for_id:     false,
        },
    ).expect("TL code generation failed");

    println!("cargo:rerun-if-changed=tl/api.tl");
}

In lib.rs:

include!(concat!(env!("OUT_DIR"), "/generated_api.rs"));

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Config

Field	Description
impl_debug	#[derive(Debug)] on all types
impl_from_type	From<types::T> for enums::E
impl_from_enum	TryFrom<enums::E> for types::T
impl_serde	serde::Serialize / Deserialize
name_for_id	name_for_id(u32) -> Option<&'static str> CRC32 lookup

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Generated Output

For each TL constructor, generates a Rust struct with Serializable / Deserializable impls. For each abstract type, generates a Rust enum with discriminated deserialization on the 4-byte CRC32 ID. For each function, generates a struct implementing RemoteCall with the correct return type.

Module layout:

generated.rs
├ mod types      one struct per TL constructor
├ mod enums      one enum per TL abstract type
└ mod functions
  ├ mod account
  ├ mod auth
  ├ mod channels
  ├ mod messages
  └ ...

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Stack position

ferogram-tl-types  (consumes generated code)
└ ferogram-tl-gen  <-- here
  └ ferogram-tl-parser

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License

MIT or Apache-2.0, at your option. See LICENSE-MIT and LICENSE-APACHE.

Ankit Chaubey - github.com/ankit-chaubey