anchor_attribute_program/
lib.rs

1extern crate proc_macro;
2
3mod declare_program;
4
5use declare_program::DeclareProgram;
6use quote::ToTokens;
7use syn::parse_macro_input;
8
9/// The `#[program]` attribute defines the module containing all instruction
10/// handlers defining all entries into a Solana program.
11#[proc_macro_attribute]
12pub fn program(
13    _args: proc_macro::TokenStream,
14    input: proc_macro::TokenStream,
15) -> proc_macro::TokenStream {
16    let program = parse_macro_input!(input as anchor_syn::Program);
17    let program_tokens = program.to_token_stream();
18
19    #[cfg(feature = "idl-build")]
20    {
21        use anchor_syn::idl::gen_idl_print_fn_program;
22        let idl_tokens = gen_idl_print_fn_program(&program);
23        return proc_macro::TokenStream::from(quote::quote! {
24            #program_tokens
25            #idl_tokens
26        });
27    }
28
29    #[allow(unreachable_code)]
30    proc_macro::TokenStream::from(program_tokens)
31}
32
33/// Declare an external program based on its IDL.
34///
35/// The IDL of the program must exist in a directory named `idls`. This directory can be at any
36/// depth, e.g. both inside the program's directory (`<PROGRAM_DIR>/idls`) and inside Anchor
37/// workspace root directory (`<PROGRAM_DIR>/../../idls`) are valid.
38///
39/// # Usage
40///
41/// ```rs
42/// declare_program!(program_name);
43/// ```
44///
45/// This generates a module named `program_name` that can be used to interact with the program
46/// without having to add the program's crate as a dependency.
47///
48/// Both on-chain and off-chain usage is supported.
49///
50/// Use `cargo doc --open` to see the generated modules and their documentation.
51///
52/// # Note
53///
54/// Re-defining the same program to use the same definitions should be avoided since this results
55/// in a larger binary size.
56///
57/// A program should only be defined once. If you have multiple programs that depend on the same
58/// definition, you should consider creating a separate crate for the external program definition
59/// and reusing it in your programs.
60///
61/// # Example
62///
63/// A full on-chain CPI usage example can be found [here].
64///
65/// [here]: https://github.com/coral-xyz/anchor/tree/v1.0.0-rc.2/tests/declare-program
66#[proc_macro]
67pub fn declare_program(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
68    parse_macro_input!(input as DeclareProgram)
69        .to_token_stream()
70        .into()
71}
72
73/// This attribute is used to override the Anchor defaults of program instructions.
74///
75/// # Arguments
76///
77/// - `discriminator`: Override the default 8-byte discriminator
78///
79///     **Usage:** `discriminator = <CONST_EXPR>`
80///
81///     All constant expressions are supported.
82///
83///     **Examples:**
84///
85///     - `discriminator = 1` (shortcut for `[1]`)
86///     - `discriminator = [1, 2, 3, 4]`
87///     - `discriminator = b"hi"`
88///     - `discriminator = MY_DISC`
89///     - `discriminator = get_disc(...)`
90///
91/// # Example
92///
93/// ```ignore
94/// use anchor_lang::prelude::*;
95///
96/// declare_id!("CustomDiscriminator111111111111111111111111");
97///
98/// #[program]
99/// pub mod custom_discriminator {
100///     use super::*;
101///
102///     #[instruction(discriminator = [1, 2, 3, 4])]
103///     pub fn my_ix(_ctx: Context<MyIx>) -> Result<()> {
104///         Ok(())
105///     }
106/// }
107///
108/// #[derive(Accounts)]
109/// pub struct MyIx<'info> {
110///     pub signer: Signer<'info>,
111/// }
112/// ```
113#[proc_macro_attribute]
114pub fn instruction(
115    _args: proc_macro::TokenStream,
116    input: proc_macro::TokenStream,
117) -> proc_macro::TokenStream {
118    // This macro itself is a no-op, but the `#[program]` macro will detect this attribute and use
119    // the arguments to transform the instruction.
120    input
121}
anchor_attribute_program/lib.rs

anchor_attribute_program/
lib.rs
