Expand description
§mattro-rs
mattro
is a proc_macro attribute parser for Rust.
§Usage
Add this to your Cargo.toml:
[dependencies]
mattro = "0.1.2"
You can parse:
Attribute
usingMacroAttribute::new(attribute)
AttributeArgs
usingMacroAttribute::from_attribute_args(path, args, style)
§Example
Parsing AttributeArgs
:
main.rs
#[my_attribute(text="some text", number=120, array=1,2,3)]
fn main() {}
lib.rs
use mattro::MacroAttribute;
use proc_macro::TokenStream;
#[proc_macro_attribute]
pub fn my_attribute(attribute: TokenStream, item: TokenStream) -> TokenStream {
let tokens = attribute.clone();
let attribute_args: syn::AttributeArgs = syn::parse_macro_input!(tokens);
// Creates a `MacroAttribute` from `AttributeArgs`.
let attr = MacroAttribute::from_attribute_args(
// Path of the attribute
"my_attribute",
// The `AttributeArgs`
attribute_args,
// The attribute style `inner` or `outer`
syn::AttrStyle::Outer
);
// Prints all the `MetaItem`s
for meta_item in &attr {
println!("{:#?}", meta_item);
}
// Returns the decorated item
item
}
This prints out:
NameValue(
NameValue {
name: "text",
value: Literal(
Str(
LitStr {
token: "some text",
},
),
),
},
)
NameValue(
NameValue {
name: "number",
value: Literal(
Int(
LitInt {
token: 120,
},
),
),
},
)
NameValue(
NameValue {
name: "array",
value: Array(
[
Int(
LitInt {
token: 1,
},
),
Int(
LitInt {
token: 2,
},
),
Int(
LitInt {
token: 3,
},
),
],
),
},
)
§You could convert the attribute into a name-value
pairs
// Converts the attribute into a `name-value` attribute
let name_values_attributes = attr.into_name_values().unwrap();
// Iterate over the `name-value` pairs
for (name, value) in &name_values_attributes {
println!("{:7} => {}", name, value);
}
This prints out:
text => "some text"
number => 120
array => [1, 2, 3]
Structs§
- An iterator over the values of a
NameValueAttribute
. - An iterator by reference over the values of a
NameValueAttribute
. - Represents a macro attribute and its arguments like:
- Represents an attribute name-value:
name="value"
. - Represents a
name-value
attribute like#[attribute(name="value")]
.
Enums§
- Represents the data in an attribute.
- Represents an error when parsing a name-value attribute.
- Represents a value for a
name-value
attribute.