Struct proc_macro2::Punct

source · 
pub struct Punct { /* private fields */ }
Expand description

A Punct is a single punctuation character like +, - or #.

Multicharacter operators like += are represented as two instances of Punct with different forms of Spacing returned.

Implementations§

Creates a new Punct from the given character and spacing.

The ch argument must be a valid punctuation character permitted by the language, otherwise the function will panic.

The returned Punct will have the default span of Span::call_site() which can be further configured with the set_span method below.

Examples found in repository?
src/fallback.rs (line 104)
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    fn push_negative_literal(mut vec: RcVecMut<TokenTree>, mut literal: Literal) {
        literal.repr.remove(0);
        let mut punct = crate::Punct::new('-', Spacing::Alone);
        punct.set_span(crate::Span::_new_stable(literal.span));
        vec.push(TokenTree::Punct(punct));
        vec.push(TokenTree::Literal(crate::Literal::_new_stable(literal)));
    }
More examples
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src/parse.rs (line 758)
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fn punct(input: Cursor) -> PResult<Punct> {
    let (rest, ch) = punct_char(input)?;
    if ch == '\'' {
        if ident_any(rest)?.0.starts_with("'") {
            Err(Reject)
        } else {
            Ok((rest, Punct::new('\'', Spacing::Joint)))
        }
    } else {
        let kind = match punct_char(rest) {
            Ok(_) => Spacing::Joint,
            Err(Reject) => Spacing::Alone,
        };
        Ok((rest, Punct::new(ch, kind)))
    }
}

fn punct_char(input: Cursor) -> PResult<char> {
    if input.starts_with("//") || input.starts_with("/*") {
        // Do not accept `/` of a comment as a punct.
        return Err(Reject);
    }

    let mut chars = input.chars();
    let first = match chars.next() {
        Some(ch) => ch,
        None => {
            return Err(Reject);
        }
    };
    let recognized = "~!@#$%^&*-=+|;:,<.>/?'";
    if recognized.contains(first) {
        Ok((input.advance(first.len_utf8()), first))
    } else {
        Err(Reject)
    }
}

fn doc_comment<'a>(input: Cursor<'a>, trees: &mut TokenStreamBuilder) -> PResult<'a, ()> {
    #[cfg(span_locations)]
    let lo = input.off;
    let (rest, (comment, inner)) = doc_comment_contents(input)?;
    let span = crate::Span::_new_stable(Span {
        #[cfg(span_locations)]
        lo,
        #[cfg(span_locations)]
        hi: rest.off,
    });

    let mut scan_for_bare_cr = comment;
    while let Some(cr) = scan_for_bare_cr.find('\r') {
        let rest = &scan_for_bare_cr[cr + 1..];
        if !rest.starts_with('\n') {
            return Err(Reject);
        }
        scan_for_bare_cr = rest;
    }

    let mut pound = Punct::new('#', Spacing::Alone);
    pound.set_span(span);
    trees.push_token_from_parser(TokenTree::Punct(pound));

    if inner {
        let mut bang = Punct::new('!', Spacing::Alone);
        bang.set_span(span);
        trees.push_token_from_parser(TokenTree::Punct(bang));
    }

    let doc_ident = crate::Ident::new("doc", span);
    let mut equal = Punct::new('=', Spacing::Alone);
    equal.set_span(span);
    let mut literal = crate::Literal::string(comment);
    literal.set_span(span);
    let mut bracketed = TokenStreamBuilder::with_capacity(3);
    bracketed.push_token_from_parser(TokenTree::Ident(doc_ident));
    bracketed.push_token_from_parser(TokenTree::Punct(equal));
    bracketed.push_token_from_parser(TokenTree::Literal(literal));
    let group = Group::new(Delimiter::Bracket, bracketed.build());
    let mut group = crate::Group::_new_stable(group);
    group.set_span(span);
    trees.push_token_from_parser(TokenTree::Group(group));

    Ok((rest, ()))
}
src/wrapper.rs (line 336)
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    fn next(&mut self) -> Option<TokenTree> {
        let token = match self {
            TokenTreeIter::Compiler(iter) => iter.next()?,
            TokenTreeIter::Fallback(iter) => return iter.next(),
        };
        Some(match token {
            proc_macro::TokenTree::Group(tt) => crate::Group::_new(Group::Compiler(tt)).into(),
            proc_macro::TokenTree::Punct(tt) => {
                let spacing = match tt.spacing() {
                    proc_macro::Spacing::Joint => Spacing::Joint,
                    proc_macro::Spacing::Alone => Spacing::Alone,
                };
                let mut o = Punct::new(tt.as_char(), spacing);
                o.set_span(crate::Span::_new(Span::Compiler(tt.span())));
                o.into()
            }
            proc_macro::TokenTree::Ident(s) => crate::Ident::_new(Ident::Compiler(s)).into(),
            proc_macro::TokenTree::Literal(l) => crate::Literal::_new(Literal::Compiler(l)).into(),
        })
    }

Returns the value of this punctuation character as char.

Examples found in repository?
src/wrapper.rs (line 161)
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fn into_compiler_token(token: TokenTree) -> proc_macro::TokenTree {
    match token {
        TokenTree::Group(tt) => tt.inner.unwrap_nightly().into(),
        TokenTree::Punct(tt) => {
            let spacing = match tt.spacing() {
                Spacing::Joint => proc_macro::Spacing::Joint,
                Spacing::Alone => proc_macro::Spacing::Alone,
            };
            let mut punct = proc_macro::Punct::new(tt.as_char(), spacing);
            punct.set_span(tt.span().inner.unwrap_nightly());
            punct.into()
        }
        TokenTree::Ident(tt) => tt.inner.unwrap_nightly().into(),
        TokenTree::Literal(tt) => tt.inner.unwrap_nightly().into(),
    }
}

Returns the spacing of this punctuation character, indicating whether it’s immediately followed by another Punct in the token stream, so they can potentially be combined into a multicharacter operator (Joint), or it’s followed by some other token or whitespace (Alone) so the operator has certainly ended.

Examples found in repository?
src/fallback.rs (line 215)
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    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let mut joint = false;
        for (i, tt) in self.inner.iter().enumerate() {
            if i != 0 && !joint {
                write!(f, " ")?;
            }
            joint = false;
            match tt {
                TokenTree::Group(tt) => Display::fmt(tt, f),
                TokenTree::Ident(tt) => Display::fmt(tt, f),
                TokenTree::Punct(tt) => {
                    joint = tt.spacing() == Spacing::Joint;
                    Display::fmt(tt, f)
                }
                TokenTree::Literal(tt) => Display::fmt(tt, f),
            }?;
        }

        Ok(())
    }
More examples
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src/wrapper.rs (line 157)
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fn into_compiler_token(token: TokenTree) -> proc_macro::TokenTree {
    match token {
        TokenTree::Group(tt) => tt.inner.unwrap_nightly().into(),
        TokenTree::Punct(tt) => {
            let spacing = match tt.spacing() {
                Spacing::Joint => proc_macro::Spacing::Joint,
                Spacing::Alone => proc_macro::Spacing::Alone,
            };
            let mut punct = proc_macro::Punct::new(tt.as_char(), spacing);
            punct.set_span(tt.span().inner.unwrap_nightly());
            punct.into()
        }
        TokenTree::Ident(tt) => tt.inner.unwrap_nightly().into(),
        TokenTree::Literal(tt) => tt.inner.unwrap_nightly().into(),
    }
}

Returns the span for this punctuation character.

Examples found in repository?
src/lib.rs (line 583)
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    pub fn span(&self) -> Span {
        match self {
            TokenTree::Group(t) => t.span(),
            TokenTree::Ident(t) => t.span(),
            TokenTree::Punct(t) => t.span(),
            TokenTree::Literal(t) => t.span(),
        }
    }
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src/wrapper.rs (line 162)
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fn into_compiler_token(token: TokenTree) -> proc_macro::TokenTree {
    match token {
        TokenTree::Group(tt) => tt.inner.unwrap_nightly().into(),
        TokenTree::Punct(tt) => {
            let spacing = match tt.spacing() {
                Spacing::Joint => proc_macro::Spacing::Joint,
                Spacing::Alone => proc_macro::Spacing::Alone,
            };
            let mut punct = proc_macro::Punct::new(tt.as_char(), spacing);
            punct.set_span(tt.span().inner.unwrap_nightly());
            punct.into()
        }
        TokenTree::Ident(tt) => tt.inner.unwrap_nightly().into(),
        TokenTree::Literal(tt) => tt.inner.unwrap_nightly().into(),
    }
}

Configure the span for this punctuation character.

Examples found in repository?
src/lib.rs (line 597)
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    pub fn set_span(&mut self, span: Span) {
        match self {
            TokenTree::Group(t) => t.set_span(span),
            TokenTree::Ident(t) => t.set_span(span),
            TokenTree::Punct(t) => t.set_span(span),
            TokenTree::Literal(t) => t.set_span(span),
        }
    }
More examples
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src/fallback.rs (line 105)
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    fn push_negative_literal(mut vec: RcVecMut<TokenTree>, mut literal: Literal) {
        literal.repr.remove(0);
        let mut punct = crate::Punct::new('-', Spacing::Alone);
        punct.set_span(crate::Span::_new_stable(literal.span));
        vec.push(TokenTree::Punct(punct));
        vec.push(TokenTree::Literal(crate::Literal::_new_stable(literal)));
    }
src/wrapper.rs (line 337)
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    fn next(&mut self) -> Option<TokenTree> {
        let token = match self {
            TokenTreeIter::Compiler(iter) => iter.next()?,
            TokenTreeIter::Fallback(iter) => return iter.next(),
        };
        Some(match token {
            proc_macro::TokenTree::Group(tt) => crate::Group::_new(Group::Compiler(tt)).into(),
            proc_macro::TokenTree::Punct(tt) => {
                let spacing = match tt.spacing() {
                    proc_macro::Spacing::Joint => Spacing::Joint,
                    proc_macro::Spacing::Alone => Spacing::Alone,
                };
                let mut o = Punct::new(tt.as_char(), spacing);
                o.set_span(crate::Span::_new(Span::Compiler(tt.span())));
                o.into()
            }
            proc_macro::TokenTree::Ident(s) => crate::Ident::_new(Ident::Compiler(s)).into(),
            proc_macro::TokenTree::Literal(l) => crate::Literal::_new(Literal::Compiler(l)).into(),
        })
    }
src/parse.rs (line 811)
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fn doc_comment<'a>(input: Cursor<'a>, trees: &mut TokenStreamBuilder) -> PResult<'a, ()> {
    #[cfg(span_locations)]
    let lo = input.off;
    let (rest, (comment, inner)) = doc_comment_contents(input)?;
    let span = crate::Span::_new_stable(Span {
        #[cfg(span_locations)]
        lo,
        #[cfg(span_locations)]
        hi: rest.off,
    });

    let mut scan_for_bare_cr = comment;
    while let Some(cr) = scan_for_bare_cr.find('\r') {
        let rest = &scan_for_bare_cr[cr + 1..];
        if !rest.starts_with('\n') {
            return Err(Reject);
        }
        scan_for_bare_cr = rest;
    }

    let mut pound = Punct::new('#', Spacing::Alone);
    pound.set_span(span);
    trees.push_token_from_parser(TokenTree::Punct(pound));

    if inner {
        let mut bang = Punct::new('!', Spacing::Alone);
        bang.set_span(span);
        trees.push_token_from_parser(TokenTree::Punct(bang));
    }

    let doc_ident = crate::Ident::new("doc", span);
    let mut equal = Punct::new('=', Spacing::Alone);
    equal.set_span(span);
    let mut literal = crate::Literal::string(comment);
    literal.set_span(span);
    let mut bracketed = TokenStreamBuilder::with_capacity(3);
    bracketed.push_token_from_parser(TokenTree::Ident(doc_ident));
    bracketed.push_token_from_parser(TokenTree::Punct(equal));
    bracketed.push_token_from_parser(TokenTree::Literal(literal));
    let group = Group::new(Delimiter::Bracket, bracketed.build());
    let mut group = crate::Group::_new_stable(group);
    group.set_span(span);
    trees.push_token_from_parser(TokenTree::Group(group));

    Ok((rest, ()))
}

Trait Implementations§

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more

Prints the punctuation character as a string that should be losslessly convertible back into the same character.

Formats the value using the given formatter. Read more
Converts to this type from the input type.

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.