Add macro lifetime specifier

Allows accepting a lifetime as a parameter to a macro

Author: Diggsey

src/libsyntax/ext/tt/macro_parser.rs

@@ -540,6 +540,14 @@ pub fn parse_nt(p: &mut Parser, sp: Span, name: &str) -> Nonterminal {
                              &token_str[..])))
         }
       },
+      "lifetime" => match p.token {
+        token::Lifetime(sn) => { panictry!(p.bump()); token::NtLifetime(Box::new(sn)) }
+        _ => {
+            let token_str = pprust::token_to_string(&p.token);
+            panic!(p.fatal(&format!("expected lifetime, found {}",
+                             &token_str[..])))
+        }
+      },
       "path" => {
         token::NtPath(Box::new(panictry!(p.parse_path(LifetimeAndTypesWithoutColons))))
       }

src/libsyntax/ext/tt/macro_rules.rs

@@ -505,8 +505,8 @@ fn is_in_follow(_: &ExtCtxt, tok: &Token, frag: &str) -> Result<bool, String> {
                     _ => Ok(false)
                 }
             },
-            "ident" => {
-                // being a single token, idents are harmless
+            "ident" | "lifetime" => {
+                // being a single token, idents and lifetimes are harmless
                 Ok(true)
             },
             "meta" | "tt" => {

src/libsyntax/ext/tt/transcribe.rs

@@ -15,7 +15,7 @@ use codemap::{Span, DUMMY_SP};
 use diagnostic::SpanHandler;
 use ext::tt::macro_parser::{NamedMatch, MatchedSeq, MatchedNonterminal};
 use parse::token::{Eof, DocComment, Interpolated, MatchNt, SubstNt};
-use parse::token::{Token, NtIdent, SpecialMacroVar};
+use parse::token::{Token, NtIdent, NtLifetime, SpecialMacroVar};
 use parse::token;
 use parse::lexer::TokenAndSpan;
 
@@ -299,6 +299,11 @@ pub fn tt_next_token(r: &mut TtReader) -> TokenAndSpan {
                                 r.cur_tok = token::Ident(**sn, b);
                                 return ret_val;
                             }
+                            MatchedNonterminal(NtLifetime(ref sn)) => {
+                                r.cur_span = sp;
+                                r.cur_tok = token::Lifetime(**sn);
+                                return ret_val;
+                            }
                             MatchedNonterminal(ref other_whole_nt) => {
                                 // FIXME(pcwalton): Bad copy.
                                 r.cur_span = sp;

src/libsyntax/fold.rs

@@ -679,6 +679,8 @@ pub fn noop_fold_interpolated<T: Folder>(nt: token::Nonterminal, fld: &mut T)
         token::NtTy(ty) => token::NtTy(fld.fold_ty(ty)),
         token::NtIdent(id, is_mod_name) =>
             token::NtIdent(Box::new(fld.fold_ident(*id)), is_mod_name),
+        token::NtLifetime(id) => token::NtLifetime(Box::new(
+            fld.fold_lifetime(ast_util::name_to_dummy_lifetime(id.name)).name.ident())),
         token::NtMeta(meta_item) => token::NtMeta(fld.fold_meta_item(meta_item)),
         token::NtPath(path) => token::NtPath(Box::new(fld.fold_path(*path))),
         token::NtTT(tt) => token::NtTT(P(fld.fold_tt(&*tt))),

src/libsyntax/parse/parser.rs

@@ -537,6 +537,9 @@ impl<'a> Parser<'a> {
             token::Interpolated(token::NtIdent(..)) => {
                 self.bug("ident interpolation not converted to real token");
             }
+            token::Interpolated(token::NtLifetime(..)) => {
+                self.bug("lifetime interpolation not converted to real token");
+            }
             _ => {
                 let token_str = self.this_token_to_string();
                 Err(self.fatal(&format!("expected ident, found `{}`",

src/libsyntax/parse/token.rs

@@ -377,6 +377,7 @@ pub enum Nonterminal {
     NtExpr(P<ast::Expr>),
     NtTy(P<ast::Ty>),
     NtIdent(Box<ast::Ident>, IdentStyle),
+    NtLifetime(Box<ast::Ident>),
     /// Stuff inside brackets for attributes
     NtMeta(P<ast::MetaItem>),
     NtPath(Box<ast::Path>),
@@ -399,6 +400,7 @@ impl fmt::Debug for Nonterminal {
             NtExpr(..) => f.pad("NtExpr(..)"),
             NtTy(..) => f.pad("NtTy(..)"),
             NtIdent(..) => f.pad("NtIdent(..)"),
+            NtLifetime(..) => f.pad("NtLifetime(..)"),
             NtMeta(..) => f.pad("NtMeta(..)"),
             NtPath(..) => f.pad("NtPath(..)"),
             NtTT(..) => f.pad("NtTT(..)"),

src/libsyntax/print/pprust.rs

@@ -296,6 +296,7 @@ pub fn token_to_string(tok: &Token) -> String {
             token::NtStmt(ref e)        => stmt_to_string(&**e),
             token::NtPat(ref e)         => pat_to_string(&**e),
             token::NtIdent(ref e, _)    => ident_to_string(&**e),
+            token::NtLifetime(ref e)    => lifetime_to_string(&ast_util::name_to_dummy_lifetime(e.name)),
             token::NtTT(ref e)          => tt_to_string(&**e),
             token::NtArm(ref e)         => arm_to_string(&*e),
             token::NtImplItem(ref e)    => impl_item_to_string(&**e),

src/test/run-pass/macro-interpolation.rs

@@ -10,8 +10,9 @@
 
 
 macro_rules! overly_complicated {
-    ($fnname:ident, $arg:ident, $ty:ty, $body:block, $val:expr, $pat:pat, $res:path) =>
+    ($fnname:ident, $arg:ident, $ty:ty, $body:block, $val:expr, $pat:pat, $res:path, $label:lifetime) =>
     ({
+        $label: loop { break $label; }
         fn $fnname($arg: $ty) -> Option<$ty> $body
         match $fnname($val) {
           Some($pat) => {
@@ -25,6 +26,6 @@ macro_rules! overly_complicated {
 
 pub fn main() {
     assert!(overly_complicated!(f, x, Option<usize>, { return Some(x); },
-                               Some(8), Some(y), y) == 8)
+                               Some(8), Some(y), y, 'test) == 8)
 
 }