Function syn::parse_str

pub fn parse_str<T: Parse>(s: &str) -> Result<T>

Available on crate feature parsing only.

Parse a string of Rust code into the chosen syntax tree node.

This function is available only if Syn is built with the "parsing" feature.

Hygiene

Every span in the resulting syntax tree will be set to resolve at the macro call site.

Examples

use syn::{Expr, Result};

fn run() -> Result<()> {
    let code = "assert_eq!(u8::max_value(), 255)";
    let expr = syn::parse_str::<Expr>(code)?;
    println!("{:#?}", expr);
    Ok(())
}

Examples found in repository

src/lib.rs (line 981)

pub fn parse_file(mut content: &str) -> Result<File> {
    // Strip the BOM if it is present
    const BOM: &str = "\u{feff}";
    if content.starts_with(BOM) {
        content = &content[BOM.len()..];
    }

    let mut shebang = None;
    if content.starts_with("#!") {
        let rest = whitespace::skip(&content[2..]);
        if !rest.starts_with('[') {
            if let Some(idx) = content.find('\n') {
                shebang = Some(content[..idx].to_string());
                content = &content[idx..];
            } else {
                shebang = Some(content.to_string());
                content = "";
            }
        }
    }

    let mut file: File = parse_str(content)?;
    file.shebang = shebang;
    Ok(file)
}

src/expr.rs (line 2904)

    fn multi_index(e: &mut Expr, dot_token: &mut Token![.], float: LitFloat) -> Result<bool> {
        let mut float_repr = float.to_string();
        let trailing_dot = float_repr.ends_with('.');
        if trailing_dot {
            float_repr.truncate(float_repr.len() - 1);
        }
        for part in float_repr.split('.') {
            let index = crate::parse_str(part).map_err(|err| Error::new(float.span(), err))?;
            #[cfg(not(syn_no_const_vec_new))]
            let base = mem::replace(e, Expr::DUMMY);
            #[cfg(syn_no_const_vec_new)]
            let base = mem::replace(e, Expr::Verbatim(TokenStream::new()));
            *e = Expr::Field(ExprField {
                attrs: Vec::new(),
                base: Box::new(base),
                dot_token: Token![.](dot_token.span),
                member: Member::Unnamed(index),
            });
            *dot_token = Token![.](float.span());
        }
        Ok(!trailing_dot)
    }