diff options
Diffstat (limited to 'vendor/rustversion/src/token.rs')
-rw-r--r-- | vendor/rustversion/src/token.rs | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/vendor/rustversion/src/token.rs b/vendor/rustversion/src/token.rs new file mode 100644 index 000000000..ebb6f1c01 --- /dev/null +++ b/vendor/rustversion/src/token.rs @@ -0,0 +1,78 @@ +use crate::error::{Error, Result}; +use crate::iter::Iter; +use proc_macro::{Delimiter, Group, Ident, Literal, Span, TokenTree}; + +pub fn parse_punct(iter: Iter, ch: char) -> Result<()> { + match iter.next() { + Some(TokenTree::Punct(ref punct)) if punct.as_char() == ch => Ok(()), + unexpected => { + let span = unexpected + .as_ref() + .map_or_else(Span::call_site, TokenTree::span); + Err(Error::new(span, format!("expected `{}`", ch))) + } + } +} + +pub fn parse_optional_punct(iter: Iter, ch: char) -> Option<()> { + match iter.peek() { + Some(TokenTree::Punct(punct)) if punct.as_char() == ch => iter.next().map(drop), + _ => None, + } +} + +pub fn parse_optional_keyword(iter: Iter, keyword: &str) -> Option<Span> { + match iter.peek() { + Some(TokenTree::Ident(ident)) if ident.to_string() == keyword => { + Some(iter.next().unwrap().span()) + } + _ => None, + } +} + +pub fn parse_literal(iter: Iter) -> Result<Literal> { + match iter.next() { + Some(TokenTree::Literal(literal)) => Ok(literal), + unexpected => { + let span = unexpected + .as_ref() + .map_or_else(Span::call_site, TokenTree::span); + Err(Error::new(span, "expected literal")) + } + } +} + +pub fn parse_paren(introducer: &Ident, iter: Iter) -> Result<Group> { + match iter.peek() { + Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Parenthesis => { + match iter.next() { + Some(TokenTree::Group(group)) => Ok(group), + _ => unreachable!(), + } + } + Some(unexpected) => Err(Error::new(unexpected.span(), "expected `(`")), + None => Err(Error::new( + introducer.span(), + format!("expected `(` after `{}`", introducer), + )), + } +} + +pub fn parse_optional_paren(iter: Iter) -> Option<Group> { + match iter.peek() { + Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Parenthesis => { + match iter.next() { + Some(TokenTree::Group(group)) => Some(group), + _ => unreachable!(), + } + } + _ => None, + } +} + +pub fn parse_end(iter: Iter) -> Result<()> { + match iter.next() { + None => Ok(()), + Some(unexpected) => Err(Error::new(unexpected.span(), "unexpected token")), + } +} |