Macro handlebars::handlebars_helper [−][src]
macro_rules! handlebars_helper { ($struct_name : ident : | $($name : ident : $tpe : tt), * $($(,) ? { $($hash_name : ident : $hash_tpe : tt = $dft_val : literal), * }) ? $($(,) ? * $args : ident) ? $($(,) ? * * $kwargs : ident) ? | $body : expr) => { ... }; (@ as_json_value $x : ident, object) => { ... }; (@ as_json_value $x : ident, array) => { ... }; (@ as_json_value $x : ident, str) => { ... }; (@ as_json_value $x : ident, i64) => { ... }; (@ as_json_value $x : ident, u64) => { ... }; (@ as_json_value $x : ident, f64) => { ... }; (@ as_json_value $x : ident, bool) => { ... }; (@ as_json_value $x : ident, null) => { ... }; (@ as_json_value $x : ident, Json) => { ... }; }
Expand description
Macro that allows you to quickly define a handlebars helper by passing a name and a closure.
There are several types of arguments available to closure:
- Parameters are mapped to closure arguments one by one. Any declared parameters are required
- Hash are mapped as named arguments and declared in a bracket block. All named arguments are optional so default value is required.
- An optional
*args
provides a vector of all helper parameters. - An optional
**kwargs
provides a map of all helper hash.
Examples
#[macro_use] extern crate handlebars; #[macro_use] extern crate serde_json; handlebars_helper!(is_above_10: |x: u64| x > 10); handlebars_helper!(is_above: |x: u64, { compare: u64 = 10 }| x > compare); let mut handlebars = handlebars::Handlebars::new(); handlebars.register_helper("is-above-10", Box::new(is_above_10)); handlebars.register_helper("is-above", Box::new(is_above)); let result = handlebars .render_template("{{#if (is-above-10 12)}}great!{{else}}okay{{/if}}", &json!({})) .unwrap(); assert_eq!(&result, "great!"); let result2 = handlebars .render_template("{{#if (is-above 12 compare=10)}}great!{{else}}okay{{/if}}", &json!({})) .unwrap(); assert_eq!(&result2, "great!");