diff --git a/src/lib.rs b/src/lib.rs
index 0b25ec2..f917e30 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -568,6 +568,8 @@
 }
 pub use gen::*;
 
+pub mod next;
+
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(feature = "parsing")]
diff --git a/src/next/error.rs b/src/next/error.rs
new file mode 100644
index 0000000..05473f3
--- /dev/null
+++ b/src/next/error.rs
@@ -0,0 +1,86 @@
+use std;
+use std::fmt::{self, Display};
+use std::iter::FromIterator;
+
+use proc_macro2::{
+    Delimiter, Group, Ident, LexError, Literal, Punct, Spacing, Span, TokenStream, TokenTree,
+};
+
+use buffer::Cursor;
+
+/// The result of a Syn parser.
+pub type Result<T> = std::result::Result<T, Error>;
+
+/// Error returned when a Syn parser cannot parse the input tokens.
+#[derive(Debug)]
+pub struct Error {
+    span: Span,
+    message: String,
+}
+
+impl Error {
+    pub fn new<T: Display>(span: Span, message: T) -> Self {
+        Error {
+            span: span,
+            message: message.to_string(),
+        }
+    }
+
+    /// Render the error as an invocation of [`compile_error!`].
+    ///
+    /// The [`parse_macro_input!`] macro provides a convenient way to invoke
+    /// this method correctly in a procedural macro.
+    ///
+    /// [`compile_error!`]: https://doc.rust-lang.org/std/macro.compile_error.html
+    /// [`parse_macro_input!`]: ../macro.parse_macro_input.html
+    pub fn into_compile_error(self) -> TokenStream {
+        // compile_error!($message)
+        TokenStream::from_iter(vec![
+            TokenTree::Ident(Ident::new("compile_error", self.span)),
+            TokenTree::Punct({
+                let mut punct = Punct::new('!', Spacing::Alone);
+                punct.set_span(self.span);
+                punct
+            }),
+            TokenTree::Group({
+                let mut group = Group::new(Delimiter::Brace, {
+                    TokenStream::from_iter(vec![TokenTree::Literal({
+                        let mut string = Literal::string(&self.message);
+                        string.set_span(self.span);
+                        string
+                    })])
+                });
+                group.set_span(self.span);
+                group
+            }),
+        ])
+    }
+}
+
+// Not public API.
+#[doc(hidden)]
+pub fn new_at<T: Display>(scope: Span, cursor: Cursor, message: T) -> Error {
+    if cursor.eof() {
+        Error::new(scope, format!("unexpected end of input, {}", message))
+    } else {
+        Error::new(cursor.span(), message)
+    }
+}
+
+impl Display for Error {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str(&self.message)
+    }
+}
+
+impl std::error::Error for Error {
+    fn description(&self) -> &str {
+        "parse error"
+    }
+}
+
+impl From<LexError> for Error {
+    fn from(err: LexError) -> Self {
+        Error::new(Span::call_site(), format!("{:?}", err))
+    }
+}
diff --git a/src/next/export.rs b/src/next/export.rs
new file mode 100644
index 0000000..cceed14
--- /dev/null
+++ b/src/next/export.rs
@@ -0,0 +1,4 @@
+pub use std::result::Result::{Err, Ok};
+
+#[cfg(feature = "proc-macro")]
+pub use proc_macro::TokenStream;
diff --git a/src/next/group.rs b/src/next/group.rs
new file mode 100644
index 0000000..40317bf
--- /dev/null
+++ b/src/next/group.rs
@@ -0,0 +1,90 @@
+use proc_macro2::Delimiter;
+
+use super::parse::{ParseBuffer, Result};
+use super::token;
+
+pub struct Braces<'a> {
+    pub token: token::Brace,
+    pub content: ParseBuffer<'a>,
+}
+
+impl<'a> ParseBuffer<'a> {
+    // Not public API.
+    #[doc(hidden)]
+    pub fn parse_braces(&self) -> Result<Braces<'a>> {
+        self.step_cursor(|cursor| {
+            if let Some((content, span, rest)) = cursor.group(Delimiter::Brace) {
+                let braces = Braces {
+                    token: token::Brace(span),
+                    content: ParseBuffer::new(span, cursor.advance(content)),
+                };
+                Ok((braces, rest))
+            } else {
+                Err(cursor.error("expected curly braces"))
+            }
+        })
+    }
+}
+
+/// Parse a set of curly braces and expose their content to subsequent parsers.
+///
+/// ```rust
+/// # extern crate syn;
+/// #
+/// use syn::{braced, Token};
+/// use syn::next::{token, Ident};
+/// use syn::next::parse::{Parse, ParseStream, Result};
+/// #
+/// # mod example {
+/// #     use super::{syn, braced, token, Ident, Parse, ParseStream, Result};
+/// #
+/// #     macro_rules! Token {
+/// #         (struct) => {
+/// #             syn::next::token::Struct
+/// #         };
+/// #     }
+/// #
+/// #     type Field = Ident;
+///
+/// // Parse a simplified struct syntax like:
+/// //
+/// //     struct S {
+/// //         a: A,
+/// //         b: B,
+/// //     }
+/// struct Struct {
+///     pub struct_token: Token![struct],
+///     pub ident: Ident,
+///     pub brace_token: token::Brace,
+///     pub fields: Vec<Field>,
+/// }
+///
+/// impl Parse for Struct {
+///     fn parse(input: ParseStream) -> Result<Self> {
+///         let content;
+///         Ok(Struct {
+///             struct_token: input.parse()?,
+///             ident: input.parse()?,
+///             brace_token: braced!(content in input),
+///             fields: content.parse()?,
+///         })
+///     }
+/// }
+/// # }
+/// #
+/// # fn main() {}
+/// ```
+#[macro_export]
+macro_rules! braced {
+    ($content:ident in $cursor:expr) => {
+        match $crate::next::parse::ParseBuffer::parse_braces(&$cursor) {
+            $crate::next::export::Ok(braces) => {
+                $content = braces.content;
+                braces.token
+            }
+            $crate::next::export::Err(error) => {
+                return $crate::next::export::Err(error);
+            }
+        }
+    };
+}
diff --git a/src/next/lookahead.rs b/src/next/lookahead.rs
new file mode 100644
index 0000000..256ac05
--- /dev/null
+++ b/src/next/lookahead.rs
@@ -0,0 +1,91 @@
+use std::cell::RefCell;
+
+use buffer::Cursor;
+use proc_macro2::Span;
+
+use super::error;
+use super::parse::Error;
+use super::token::Token;
+
+/// Support for checking the next token in a stream to decide how to parse.
+///
+/// Use [`ParseStream::lookahead1`] to construct this object.
+///
+/// [`ParseStream::lookahead1`]: struct.ParseBuffer.html#method.lookahead1
+pub struct Lookahead1<'a> {
+    scope: Span,
+    cursor: Cursor<'a>,
+    comparisons: RefCell<Vec<String>>,
+}
+
+impl<'a> Lookahead1<'a> {
+    // Not public API.
+    #[doc(hidden)]
+    pub fn new(scope: Span, cursor: Cursor<'a>) -> Self {
+        Lookahead1 {
+            scope: scope,
+            cursor: cursor,
+            comparisons: RefCell::new(Vec::new()),
+        }
+    }
+
+    pub fn peek<T: Peek>(&self, token: T) -> bool {
+        let _ = token;
+        if T::Token::peek(self) {
+            return true;
+        }
+        self.comparisons.borrow_mut().push(T::Token::display());
+        false
+    }
+
+    pub fn error(self) -> Error {
+        let comparisons = self.comparisons.borrow();
+        match comparisons.len() {
+            0 => if self.cursor.eof() {
+                Error::new(self.scope, "unexpected end of input")
+            } else {
+                Error::new(self.cursor.span(), "unexpected token")
+            },
+            1 => {
+                let message = format!("expected {}", comparisons[0]);
+                error::new_at(self.scope, self.cursor, message)
+            }
+            _ => {
+                let join = comparisons.join(", ");
+                let message = format!("expected one of: {}", join);
+                error::new_at(self.scope, self.cursor, message)
+            }
+        }
+    }
+}
+
+/// Types that can be parsed by looking at just one token.
+///
+/// This trait is sealed and cannot be implemented for types outside of Syn.
+pub trait Peek: private::Sealed {
+    // Not public API.
+    #[doc(hidden)]
+    type Token: Token;
+}
+
+impl<F: FnOnce(TokenMarker) -> T, T: Token> Peek for F {
+    type Token = T;
+}
+
+pub enum TokenMarker {}
+
+// Not public API.
+#[doc(hidden)]
+pub fn is_token(lookahead: &Lookahead1, repr: &'static str) -> bool {
+    if let Some((token, _rest)) = lookahead.cursor.token_tree() {
+        token.to_string() == repr
+    } else {
+        false
+    }
+}
+
+mod private {
+    use super::{Token, TokenMarker};
+    pub trait Sealed {}
+    impl<F: FnOnce(TokenMarker) -> T, T: Token> Sealed for F {}
+}
diff --git a/src/next/mod.rs b/src/next/mod.rs
new file mode 100644
index 0000000..c9d4088
--- /dev/null
+++ b/src/next/mod.rs
@@ -0,0 +1,95 @@
+#[macro_use]
+pub mod token;
+
+#[macro_use]
+pub mod parse;
+
+#[macro_use]
+mod group;
+
+mod error;
+mod lookahead;
+mod span;
+
+pub use proc_macro2::Ident;
+
+// Not public API.
+#[doc(hidden)]
+pub mod export;
+
+use std::str::FromStr;
+
+use buffer::TokenBuffer;
+#[cfg(feature = "proc-macro")]
+use proc_macro;
+use proc_macro2::{self, Span};
+
+use self::parse::{Parse, ParseBuffer, Result};
+
+/// Parse tokens of source code into the chosen syntax tree node.
+#[cfg(feature = "proc-macro")]
+pub fn parse<T: Parse>(input: proc_macro::TokenStream) -> Result<T> {
+    parse2(proc_macro2::TokenStream::from(input))
+}
+
+/// Parse a proc-macro2 token stream into the chosen syntax tree node.
+pub fn parse2<T: Parse>(input: proc_macro2::TokenStream) -> Result<T> {
+    let buf = TokenBuffer::new2(input);
+    let state = ParseBuffer::new(Span::call_site(), buf.begin());
+    T::parse(&state)
+}
+
+/// Parse a string of Rust code into the chosen syntax tree node.
+pub fn parse_str<T: Parse>(input: &str) -> Result<T> {
+    let tokens = proc_macro2::TokenStream::from_str(input)?;
+    parse2(tokens)
+}
+
+/// Parse the input TokenStream of a macro, triggering a compile error if the
+/// tokens fail to parse.
+///
+/// # Intended usage
+///
+/// ```rust
+/// # extern crate proc_macro;
+/// # extern crate syn;
+/// #
+/// use proc_macro::TokenStream;
+/// use syn::parse_macro_input;
+/// use syn::next::parse::{Parse, ParseStream, Result};
+///
+/// struct MyMacroInput {
+///     /* ... */
+/// }
+///
+/// impl Parse for MyMacroInput {
+///     fn parse(input: ParseStream) -> Result<Self> {
+///         /* ... */
+/// #       Ok(MyMacroInput {})
+///     }
+/// }
+///
+/// # const IGNORE: &str = stringify! {
+/// #[proc_macro]
+/// # };
+/// pub fn my_macro(tokens: TokenStream) -> TokenStream {
+///     let input = parse_macro_input!(tokens as MyMacroInput);
+///
+///     /* ... */
+/// #   "".parse().unwrap()
+/// }
+/// #
+/// # fn main() {}
+/// ```
+#[cfg(feature = "proc-macro")]
+#[macro_export]
+macro_rules! parse_macro_input {
+    ($tokenstream:ident as $ty:ty) => {
+        match $crate::next::parse::<$ty>($tokenstream) {
+            $crate::next::export::Ok(data) => data,
+            $crate::next::export::Err(err) => {
+                return $crate::next::export::TokenStream::from(err.into_compile_error());
+            }
+        };
+    };
+}
diff --git a/src/next/parse.rs b/src/next/parse.rs
new file mode 100644
index 0000000..447b8e1
--- /dev/null
+++ b/src/next/parse.rs
@@ -0,0 +1,135 @@
+//! Parsing interface for parsing a token stream into a syntax tree node.
+
+use std::cell::Cell;
+use std::fmt::Display;
+use std::marker::PhantomData;
+use std::mem;
+use std::ops::Deref;
+
+use buffer::Cursor;
+use proc_macro2::{Ident, Span};
+
+use super::error;
+
+pub use super::error::{Error, Result};
+pub use super::lookahead::{Lookahead1, Peek};
+
+/// Parsing interface implemented by all types that can be parsed in a default
+/// way from a token stream.
+pub trait Parse: Sized {
+    fn parse(input: ParseStream) -> Result<Self>;
+}
+
+/// Input to a Syn parser function.
+pub type ParseStream<'a> = &'a ParseBuffer<'a>;
+
+/// Cursor position within a buffered token stream.
+#[derive(Clone)]
+pub struct ParseBuffer<'a> {
+    scope: Span,
+    cell: Cell<Cursor<'static>>,
+    marker: PhantomData<Cursor<'a>>,
+}
+
+// Not public API.
+#[doc(hidden)]
+#[derive(Copy, Clone)]
+pub struct StepCursor<'c, 'a> {
+    scope: Span,
+    cursor: Cursor<'c>,
+    marker: PhantomData<fn(Cursor<'c>) -> Cursor<'a>>,
+}
+
+impl<'c, 'a> Deref for StepCursor<'c, 'a> {
+    type Target = Cursor<'c>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.cursor
+    }
+}
+
+impl<'c, 'a> StepCursor<'c, 'a> {
+    // Not public API.
+    #[doc(hidden)]
+    pub fn advance(self, other: Cursor<'c>) -> Cursor<'a> {
+        unsafe { mem::transmute::<Cursor<'c>, Cursor<'a>>(other) }
+    }
+
+    // Not public API.
+    #[doc(hidden)]
+    pub fn error<T: Display>(self, message: T) -> Error {
+        error::new_at(self.scope, self.cursor, message)
+    }
+}
+
+impl<'a> ParseBuffer<'a> {
+    // Not public API.
+    #[doc(hidden)]
+    pub fn new(scope: Span, cursor: Cursor<'a>) -> Self {
+        let extend = unsafe { mem::transmute::<Cursor<'a>, Cursor<'static>>(cursor) };
+        ParseBuffer {
+            scope: scope,
+            cell: Cell::new(extend),
+            marker: PhantomData,
+        }
+    }
+
+    pub fn cursor(&self) -> Cursor<'a> {
+        self.cell.get()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.cursor().eof()
+    }
+
+    pub fn lookahead1(&self) -> Lookahead1<'a> {
+        Lookahead1::new(self.scope, self.cursor())
+    }
+
+    pub fn parse<T: Parse>(&self) -> Result<T> {
+        T::parse(self)
+    }
+
+    // Not public API.
+    #[doc(hidden)]
+    pub fn step_cursor<F, R>(&self, function: F) -> Result<R>
+    where
+        F: for<'c> FnOnce(StepCursor<'c, 'a>) -> Result<(R, Cursor<'c>)>,
+    {
+        match function(StepCursor {
+            scope: self.scope,
+            cursor: self.cell.get(),
+            marker: PhantomData,
+        }) {
+            Ok((ret, cursor)) => {
+                self.cell.set(cursor);
+                Ok(ret)
+            }
+            Err(err) => Err(err),
+        }
+    }
+}
+
+impl Parse for Ident {
+    fn parse(input: ParseStream) -> Result<Self> {
+        input.step_cursor(|cursor| {
+            if let Some((ident, rest)) = cursor.ident() {
+                Ok((ident, rest))
+            } else {
+                Err(cursor.error("expected identifier"))
+            }
+        })
+    }
+}
+
+// In reality the impl would be for Punctuated.
+impl<T: Parse> Parse for Vec<T> {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let mut vec = Vec::new();
+        while !input.is_empty() {
+            let t = input.parse::<T>()?;
+            vec.push(t);
+        }
+        Ok(vec)
+    }
+}
diff --git a/src/next/span.rs b/src/next/span.rs
new file mode 100644
index 0000000..77d4448
--- /dev/null
+++ b/src/next/span.rs
@@ -0,0 +1,73 @@
+use proc_macro2::Span;
+
+use super::lookahead::TokenMarker;
+
+pub trait IntoSpans<S> {
+    // Not public API.
+    #[doc(hidden)]
+    fn into_spans(self) -> S;
+}
+
+impl<S> IntoSpans<S> for TokenMarker {
+    fn into_spans(self) -> S {
+        match self {}
+    }
+}
+
+impl IntoSpans<[Span; 1]> for Span {
+    fn into_spans(self) -> [Span; 1] {
+        [self]
+    }
+}
+
+impl IntoSpans<[Span; 2]> for Span {
+    fn into_spans(self) -> [Span; 2] {
+        [self, self]
+    }
+}
+
+impl IntoSpans<[Span; 3]> for Span {
+    fn into_spans(self) -> [Span; 3] {
+        [self, self, self]
+    }
+}
+
+impl IntoSpans<Self> for [Span; 1] {
+    fn into_spans(self) -> Self {
+        self
+    }
+}
+
+impl IntoSpans<Self> for [Span; 2] {
+    fn into_spans(self) -> Self {
+        self
+    }
+}
+
+impl IntoSpans<Self> for [Span; 3] {
+    fn into_spans(self) -> Self {
+        self
+    }
+}
+
+pub trait FromSpans: Sized {
+    fn from_spans(spans: &[Span]) -> Self;
+}
+
+impl FromSpans for [Span; 1] {
+    fn from_spans(spans: &[Span]) -> Self {
+        [spans[0]]
+    }
+}
+
+impl FromSpans for [Span; 2] {
+    fn from_spans(spans: &[Span]) -> Self {
+        [spans[0], spans[1]]
+    }
+}
+
+impl FromSpans for [Span; 3] {
+    fn from_spans(spans: &[Span]) -> Self {
+        [spans[0], spans[1], spans[2]]
+    }
+}
diff --git a/src/next/token.rs b/src/next/token.rs
new file mode 100644
index 0000000..5b80a14
--- /dev/null
+++ b/src/next/token.rs
@@ -0,0 +1,166 @@
+//! Tokens representing Rust punctuation, keywords, and delimiters.
+
+use std::ops::{Deref, DerefMut};
+
+use proc_macro2::{Spacing, Span};
+
+use super::error::Error;
+use super::lookahead;
+use super::parse::{Lookahead1, Parse, ParseStream, Result};
+use super::span::{FromSpans, IntoSpans};
+
+/// Marker trait for types that represent single tokens.
+///
+/// This trait is sealed and cannot be implemented for types outside of Syn.
+pub trait Token: private::Sealed {
+    // Not public API.
+    #[doc(hidden)]
+    fn peek(lookahead: &Lookahead1) -> bool;
+
+    // Not public API.
+    #[doc(hidden)]
+    fn display() -> String;
+}
+
+mod private {
+    pub trait Sealed {}
+}
+
+macro_rules! impl_token {
+    ($token:tt $name:ident #[$doc:meta]) => {
+        impl Token for $name {
+            fn peek(lookahead: &Lookahead1) -> bool {
+                lookahead::is_token(lookahead, $token)
+            }
+
+            fn display() -> String {
+                concat!("`", $token, "`").to_owned()
+            }
+        }
+
+        impl private::Sealed for $name {}
+    };
+}
+
+macro_rules! define_keywords {
+    ($($token:tt pub struct $name:ident #[$doc:meta])*) => {
+        $(
+            #[$doc]
+            #[derive(Debug)]
+            pub struct $name {
+                pub span: Span,
+            }
+
+            #[doc(hidden)]
+            #[allow(non_snake_case)]
+            pub fn $name<T: IntoSpans<[Span; 1]>>(span: T) -> $name {
+                $name {
+                    span: span.into_spans()[0],
+                }
+            }
+
+            impl_token!($token $name #[$doc]);
+
+            impl Parse for $name {
+                fn parse(input: ParseStream) -> Result<Self> {
+                    parse_keyword(input, $token).map($name)
+                }
+            }
+        )*
+    };
+}
+
+macro_rules! define_punctuation {
+    ($($token:tt pub struct $name:ident/$len:tt #[$doc:meta])*) => {
+        $(
+            #[$doc]
+            #[derive(Debug)]
+            pub struct $name {
+                pub spans: [Span; $len],
+            }
+
+            impl Deref for $name {
+                type Target = [Span; $len];
+
+                fn deref(&self) -> &Self::Target {
+                    &self.spans
+                }
+            }
+
+            impl DerefMut for $name {
+                fn deref_mut(&mut self) -> &mut Self::Target {
+                    &mut self.spans
+                }
+            }
+
+            #[doc(hidden)]
+            #[allow(non_snake_case)]
+            pub fn $name<T: IntoSpans<[Span; $len]>>(spans: T) -> $name {
+                $name {
+                    spans: spans.into_spans(),
+                }
+            }
+
+            impl_token!($token $name #[$doc]);
+
+            impl Parse for $name {
+                fn parse(input: ParseStream) -> Result<Self> {
+                    parse_punctuation(input, $token).map($name::<[Span; $len]>)
+                }
+            }
+        )*
+    };
+}
+
+define_keywords! {
+    "struct" pub struct Struct /// `struct`
+    "enum"   pub struct Enum   /// `enum`
+}
+
+define_punctuation! {
+    ":"  pub struct Colon/1 /// `:`
+    ","  pub struct Comma/1 /// `,`
+    ".." pub struct Dot2/2  /// `..`
+}
+
+/// `{...}`
+#[derive(Debug)]
+pub struct Brace(pub Span);
+
+fn parse_keyword(input: ParseStream, token: &str) -> Result<Span> {
+    input.step_cursor(|cursor| {
+        if let Some((ident, rest)) = cursor.ident() {
+            if ident == token {
+                return Ok((ident.span(), rest));
+            }
+        }
+        Err(cursor.error(format!("expected `{}`", token)))
+    })
+}
+
+fn parse_punctuation<S: FromSpans>(input: ParseStream, token: &str) -> Result<S> {
+    input.step_cursor(|cursor| {
+        let mut cursor = *cursor;
+        let mut spans = [cursor.span(); 3];
+        assert!(token.len() <= spans.len());
+
+        for (i, ch) in token.chars().enumerate() {
+            match cursor.punct() {
+                Some((punct, rest)) => {
+                    spans[i] = punct.span();
+                    if punct.as_char() != ch {
+                        break;
+                    } else if i == token.len() - 1 {
+                        return Ok((S::from_spans(&spans), rest));
+                    } else if punct.spacing() != Spacing::Joint {
+                        break;
+                    }
+                    cursor = rest;
+                }
+                None => break,
+            }
+        }
+
+        Err(Error::new(spans[0], format!("expected `{}`", token)))
+    })
+}