Cairo Lang Macro

这个crate为Cairo语言提供了编写Scarb procedural宏的API。

安装

在项目目录中运行以下Cargo命令：

cargo add cairo-lang-macro

或者在Cargo.toml中添加以下行：

cairo-lang-macro = "0.2.0"

示例使用

以下是一个使用cairo-lang-macro创建自定义derive宏的完整示例：

use cairo_lang_macro::proc_macro::TokenStream;
use quote::quote;
use syn::{parse_macro_input, DeriveInput};

#[proc_macro_derive(HelloMacro)]
pub fn hello_macro_derive(input: TokenStream) -> TokenStream {
    // Parse the input tokens into a syntax tree
    let input = parse_macro_input!(input as DeriveInput);
    
    // Get the name of the struct/enum we're deriving for
    let name = input.ident;
    
    // Build the output, possibly using quote! macro
    let output = quote! {
        impl HelloMacro for #name {
            fn hello_macro() {
                println!("Hello, Macro! My name is {}!", stringify!(#name));
            }
        }
    };
    
    // Return the generated code as TokenStream
    TokenStream::from(output)
}

更复杂的示例

这是一个更复杂的示例，展示了如何使用cairo-lang-macro创建属性宏：

use cairo_lang_macro::proc_macro::TokenStream;
use quote::quote;
use syn::{parse_macro_input, ItemFn};

#[proc_mature_attribute]
pub fn log_execution_time(_attr: TokenStream, item: TokenStream) -> TokenStream {
    // Parse the input function
    let input_fn = parse_macro_input!(item as ItemFn);
    
    // Get function details
    let fn_name = &input_fn.sig.ident;
    let fn_block = &input_fn.block;
    
    // Generate the output with timing logic
    let output = quote! {
        fn #fn_name() {
            use std::time::Instant;
            let start = Instant::now();
            
            #fn_block
            
            let duration = start.elapsed();
            println!("Function {} took {:?}", stringify!(#fn_name), duration);
        }
    };
    
    TokenStream::from(output)
}

完整示例

下面是一个完整的项目示例，展示如何使用cairo-lang-macro：

1. 首先创建一个新的库项目：

cargo new --lib cairo_macro_example
cd cairo_macro_example

1. 添加依赖到Cargo.toml：

[lib]
proc-macro = true

[dependencies]
cairo-lang-macro = "0.2.0"
syn = { version = "2.0", features = ["full"] }
quote = "1.0"

1. 在src/lib.rs中实现自定义宏：

use cairo_lang_macro::proc_macro::TokenStream;
use quote::quote;
use syn::{parse_macro_input, DeriveInput};

// 自定义derive宏实现
#[proc_macro_derive(VersionInfo)]
pub fn version_info_derive(input: TokenStream) -> TokenStream {
    let input = parse_macro_input!(input as DeriveInput);
    let name = input.ident;
    
    let output = quote! {
        impl VersionInfo for #name {
            fn version() -> &'static str {
                env!("CARGO_PKG_VERSION")
            }
            
            fn author() -> &'static str {
                env!("CARGO_PKG_AUTHORS")
            }
        }
    };
    
    TokenStream::from(output)
}

// 属性宏实现
#[proc_macro_attribute]
pub fn debug_log(_attr: TokenStream, item: TokenStream) -> TokenStream {
    let input_fn = parse_macro_input!(item as ItemFn);
    let fn_name = &input_fn.sig.ident;
    let fn_block = &input_fn.block;
    
    let output = quote! {
        fn #fn_name() {
            println!("[DEBUG] Entering function: {}", stringify!(#fn_name));
            #fn_block
            println!("[DEBUG] Exiting function: {}", stringify!(#fn_name));
        }
    };
    
    TokenStream::from(output)
}

1. 在另一个项目中使用这些宏：

use cairo_macro_example::{VersionInfo, debug_log};

#[derive(VersionInfo)]
struct MyStruct;

#[debug_log]
fn my_function() {
    println!("Doing some work...");
}

fn main() {
    println!("MyStruct version: {}", MyStruct::version());
    println!("MyStruct author: {}", MyStruct::author());
    my_function();
}

使用场景

cairo-lang-macro特别适用于：

• 为Cairo语言创建自定义derive宏
• 开发代码生成工具
• 实现领域特定语言(DSL)
• 创建编译时验证和转换

版本信息

当前版本：v0.2.0
最小支持Rust版本：v1.73.0
许可证：MIT