auto merge of #10832 : chris-morgan/rust/let's-lop-lang-item-line-count, r=alexcrichton

This should make maintenance of lang items simpler and also reduces the
line count by about 201 lines.

Author: bors

src/librustc/middle/lang_items.rs

@@ -34,66 +34,26 @@ use std::hashmap::HashMap;
 use std::iter::Enumerate;
 use std::vec;
 
+// The actual lang items defined come at the end of this file in one handy table.
+// So you probably just want to nip down to the end.
+macro_rules! lets_do_this {
+    (
+        There are $num_lang_items:expr lang items.
+        $( $num:pat, $variant:ident, $name:expr, $method:ident; )*
+    ) => {
+
 pub enum LangItem {
-    FreezeTraitLangItem,               // 0
-    SendTraitLangItem,                 // 1
-    SizedTraitLangItem,                // 2
-
-    DropTraitLangItem,                 // 3
-
-    AddTraitLangItem,                  // 4
-    SubTraitLangItem,                  // 5
-    MulTraitLangItem,                  // 6
-    DivTraitLangItem,                  // 7
-    RemTraitLangItem,                  // 8
-    NegTraitLangItem,                  // 9
-    NotTraitLangItem,                  // 10
-    BitXorTraitLangItem,               // 11
-    BitAndTraitLangItem,               // 12
-    BitOrTraitLangItem,                // 13
-    ShlTraitLangItem,                  // 14
-    ShrTraitLangItem,                  // 15
-    IndexTraitLangItem,                // 16
-
-    EqTraitLangItem,                   // 17
-    OrdTraitLangItem,                  // 18
-
-    StrEqFnLangItem,                   // 19
-    UniqStrEqFnLangItem,               // 20
-    FailFnLangItem,                    // 21
-    FailBoundsCheckFnLangItem,         // 22
-    ExchangeMallocFnLangItem,          // 23
-    ClosureExchangeMallocFnLangItem,   // 24
-    ExchangeFreeFnLangItem,            // 25
-    MallocFnLangItem,                  // 26
-    FreeFnLangItem,                    // 27
-    BorrowAsImmFnLangItem,             // 28
-    BorrowAsMutFnLangItem,             // 29
-    ReturnToMutFnLangItem,             // 30
-    CheckNotBorrowedFnLangItem,        // 31
-    StrDupUniqFnLangItem,              // 32
-    RecordBorrowFnLangItem,            // 33
-    UnrecordBorrowFnLangItem,          // 34
-
-    StartFnLangItem,                   // 35
-
-    TyDescStructLangItem,              // 36
-    TyVisitorTraitLangItem,            // 37
-    OpaqueStructLangItem,              // 38
-
-    EventLoopFactoryLangItem,          // 39
-
-    TypeIdLangItem,                    // 40
+    $($variant),*
 }
 
 pub struct LanguageItems {
-    items: [Option<ast::DefId>, ..41]
+    items: [Option<ast::DefId>, ..$num_lang_items]
 }
 
 impl LanguageItems {
     pub fn new() -> LanguageItems {
         LanguageItems {
-            items: [ None, ..41 ]
+            items: [ None, ..$num_lang_items ]
         }
     }
 
@@ -103,61 +63,11 @@ impl LanguageItems {
 
     pub fn item_name(index: uint) -> &'static str {
         match index {
-            0  => "freeze",
-            1  => "send",
-            2  => "sized",
-
-            3  => "drop",
-
-            4  => "add",
-            5  => "sub",
-            6  => "mul",
-            7  => "div",
-            8  => "rem",
-            9  => "neg",
-            10 => "not",
-            11 => "bitxor",
-            12 => "bitand",
-            13 => "bitor",
-            14 => "shl",
-            15 => "shr",
-            16 => "index",
-            17 => "eq",
-            18 => "ord",
-
-            19 => "str_eq",
-            20 => "uniq_str_eq",
-            21 => "fail_",
-            22 => "fail_bounds_check",
-            23 => "exchange_malloc",
-            24 => "closure_exchange_malloc",
-            25 => "exchange_free",
-            26 => "malloc",
-            27 => "free",
-            28 => "borrow_as_imm",
-            29 => "borrow_as_mut",
-            30 => "return_to_mut",
-            31 => "check_not_borrowed",
-            32 => "strdup_uniq",
-            33 => "record_borrow",
-            34 => "unrecord_borrow",
-
-            35 => "start",
-
-            36 => "ty_desc",
-            37 => "ty_visitor",
-            38 => "opaque",
-
-            39 => "event_loop_factory",
-
-            40 => "type_id",
-
+            $( $num => $name, )*
             _ => "???"
         }
     }
 
-    // FIXME #4621: Method macros sure would be nice here.
-
     pub fn require(&self, it: LangItem) -> Result<ast::DefId, ~str> {
         match self.items[it as uint] {
             Some(id) => Ok(id),
@@ -178,133 +88,11 @@ impl LanguageItems {
         }
     }
 
-    pub fn freeze_trait(&self) -> Option<ast::DefId> {
-        self.items[FreezeTraitLangItem as uint]
-    }
-    pub fn send_trait(&self) -> Option<ast::DefId> {
-        self.items[SendTraitLangItem as uint]
-    }
-    pub fn sized_trait(&self) -> Option<ast::DefId> {
-        self.items[SizedTraitLangItem as uint]
-    }
-
-    pub fn drop_trait(&self) -> Option<ast::DefId> {
-        self.items[DropTraitLangItem as uint]
-    }
-
-    pub fn add_trait(&self) -> Option<ast::DefId> {
-        self.items[AddTraitLangItem as uint]
-    }
-    pub fn sub_trait(&self) -> Option<ast::DefId> {
-        self.items[SubTraitLangItem as uint]
-    }
-    pub fn mul_trait(&self) -> Option<ast::DefId> {
-        self.items[MulTraitLangItem as uint]
-    }
-    pub fn div_trait(&self) -> Option<ast::DefId> {
-        self.items[DivTraitLangItem as uint]
-    }
-    pub fn rem_trait(&self) -> Option<ast::DefId> {
-        self.items[RemTraitLangItem as uint]
-    }
-    pub fn neg_trait(&self) -> Option<ast::DefId> {
-        self.items[NegTraitLangItem as uint]
-    }
-    pub fn not_trait(&self) -> Option<ast::DefId> {
-        self.items[NotTraitLangItem as uint]
-    }
-    pub fn bitxor_trait(&self) -> Option<ast::DefId> {
-        self.items[BitXorTraitLangItem as uint]
-    }
-    pub fn bitand_trait(&self) -> Option<ast::DefId> {
-        self.items[BitAndTraitLangItem as uint]
-    }
-    pub fn bitor_trait(&self) -> Option<ast::DefId> {
-        self.items[BitOrTraitLangItem as uint]
-    }
-    pub fn shl_trait(&self) -> Option<ast::DefId> {
-        self.items[ShlTraitLangItem as uint]
-    }
-    pub fn shr_trait(&self) -> Option<ast::DefId> {
-        self.items[ShrTraitLangItem as uint]
-    }
-    pub fn index_trait(&self) -> Option<ast::DefId> {
-        self.items[IndexTraitLangItem as uint]
-    }
-
-    pub fn eq_trait(&self) -> Option<ast::DefId> {
-        self.items[EqTraitLangItem as uint]
-    }
-    pub fn ord_trait(&self) -> Option<ast::DefId> {
-        self.items[OrdTraitLangItem as uint]
-    }
-
-    pub fn str_eq_fn(&self) -> Option<ast::DefId> {
-        self.items[StrEqFnLangItem as uint]
-    }
-    pub fn uniq_str_eq_fn(&self) -> Option<ast::DefId> {
-        self.items[UniqStrEqFnLangItem as uint]
-    }
-    pub fn fail_fn(&self) -> Option<ast::DefId> {
-        self.items[FailFnLangItem as uint]
-    }
-    pub fn fail_bounds_check_fn(&self) -> Option<ast::DefId> {
-        self.items[FailBoundsCheckFnLangItem as uint]
-    }
-    pub fn exchange_malloc_fn(&self) -> Option<ast::DefId> {
-        self.items[ExchangeMallocFnLangItem as uint]
-    }
-    pub fn closure_exchange_malloc_fn(&self) -> Option<ast::DefId> {
-        self.items[ClosureExchangeMallocFnLangItem as uint]
-    }
-    pub fn exchange_free_fn(&self) -> Option<ast::DefId> {
-        self.items[ExchangeFreeFnLangItem as uint]
-    }
-    pub fn malloc_fn(&self) -> Option<ast::DefId> {
-        self.items[MallocFnLangItem as uint]
-    }
-    pub fn free_fn(&self) -> Option<ast::DefId> {
-        self.items[FreeFnLangItem as uint]
-    }
-    pub fn borrow_as_imm_fn(&self) -> Option<ast::DefId> {
-        self.items[BorrowAsImmFnLangItem as uint]
-    }
-    pub fn borrow_as_mut_fn(&self) -> Option<ast::DefId> {
-        self.items[BorrowAsMutFnLangItem as uint]
-    }
-    pub fn return_to_mut_fn(&self) -> Option<ast::DefId> {
-        self.items[ReturnToMutFnLangItem as uint]
-    }
-    pub fn check_not_borrowed_fn(&self) -> Option<ast::DefId> {
-        self.items[CheckNotBorrowedFnLangItem as uint]
-    }
-    pub fn strdup_uniq_fn(&self) -> Option<ast::DefId> {
-        self.items[StrDupUniqFnLangItem as uint]
-    }
-    pub fn record_borrow_fn(&self) -> Option<ast::DefId> {
-        self.items[RecordBorrowFnLangItem as uint]
-    }
-    pub fn unrecord_borrow_fn(&self) -> Option<ast::DefId> {
-        self.items[UnrecordBorrowFnLangItem as uint]
-    }
-    pub fn start_fn(&self) -> Option<ast::DefId> {
-        self.items[StartFnLangItem as uint]
-    }
-    pub fn ty_desc(&self) -> Option<ast::DefId> {
-        self.items[TyDescStructLangItem as uint]
-    }
-    pub fn ty_visitor(&self) -> Option<ast::DefId> {
-        self.items[TyVisitorTraitLangItem as uint]
-    }
-    pub fn opaque(&self) -> Option<ast::DefId> {
-        self.items[OpaqueStructLangItem as uint]
-    }
-    pub fn event_loop_factory(&self) -> Option<ast::DefId> {
-        self.items[EventLoopFactoryLangItem as uint]
-    }
-    pub fn type_id(&self) -> Option<ast::DefId> {
-        self.items[TypeIdLangItem as uint]
-    }
+    $(
+        pub fn $method(&self) -> Option<ast::DefId> {
+            self.items[$variant as uint]
+        }
+    )*
 }
 
 struct LanguageItemCollector {
@@ -343,53 +131,7 @@ impl LanguageItemCollector {
     pub fn new(session: Session) -> LanguageItemCollector {
         let mut item_refs = HashMap::new();
 
-        item_refs.insert("freeze", FreezeTraitLangItem as uint);
-        item_refs.insert("send", SendTraitLangItem as uint);
-        item_refs.insert("sized", SizedTraitLangItem as uint);
-
-        item_refs.insert("drop", DropTraitLangItem as uint);
-
-        item_refs.insert("add", AddTraitLangItem as uint);
-        item_refs.insert("sub", SubTraitLangItem as uint);
-        item_refs.insert("mul", MulTraitLangItem as uint);
-        item_refs.insert("div", DivTraitLangItem as uint);
-        item_refs.insert("rem", RemTraitLangItem as uint);
-        item_refs.insert("neg", NegTraitLangItem as uint);
-        item_refs.insert("not", NotTraitLangItem as uint);
-        item_refs.insert("bitxor", BitXorTraitLangItem as uint);
-        item_refs.insert("bitand", BitAndTraitLangItem as uint);
-        item_refs.insert("bitor", BitOrTraitLangItem as uint);
-        item_refs.insert("shl", ShlTraitLangItem as uint);
-        item_refs.insert("shr", ShrTraitLangItem as uint);
-        item_refs.insert("index", IndexTraitLangItem as uint);
-
-        item_refs.insert("eq", EqTraitLangItem as uint);
-        item_refs.insert("ord", OrdTraitLangItem as uint);
-
-        item_refs.insert("str_eq", StrEqFnLangItem as uint);
-        item_refs.insert("uniq_str_eq", UniqStrEqFnLangItem as uint);
-        item_refs.insert("fail_", FailFnLangItem as uint);
-        item_refs.insert("fail_bounds_check",
-                         FailBoundsCheckFnLangItem as uint);
-        item_refs.insert("exchange_malloc", ExchangeMallocFnLangItem as uint);
-        item_refs.insert("closure_exchange_malloc", ClosureExchangeMallocFnLangItem as uint);
-        item_refs.insert("exchange_free", ExchangeFreeFnLangItem as uint);
-        item_refs.insert("malloc", MallocFnLangItem as uint);
-        item_refs.insert("free", FreeFnLangItem as uint);
-        item_refs.insert("borrow_as_imm", BorrowAsImmFnLangItem as uint);
-        item_refs.insert("borrow_as_mut", BorrowAsMutFnLangItem as uint);
-        item_refs.insert("return_to_mut", ReturnToMutFnLangItem as uint);
-        item_refs.insert("check_not_borrowed",
-                         CheckNotBorrowedFnLangItem as uint);
-        item_refs.insert("strdup_uniq", StrDupUniqFnLangItem as uint);
-        item_refs.insert("record_borrow", RecordBorrowFnLangItem as uint);
-        item_refs.insert("unrecord_borrow", UnrecordBorrowFnLangItem as uint);
-        item_refs.insert("start", StartFnLangItem as uint);
-        item_refs.insert("ty_desc", TyDescStructLangItem as uint);
-        item_refs.insert("ty_visitor", TyVisitorTraitLangItem as uint);
-        item_refs.insert("opaque", OpaqueStructLangItem as uint);
-        item_refs.insert("event_loop_factory", EventLoopFactoryLangItem as uint);
-        item_refs.insert("type_id", TypeIdLangItem as uint);
+        $( item_refs.insert($name, $variant as uint); )*
 
         LanguageItemCollector {
             session: session,
@@ -458,3 +200,62 @@ pub fn collect_language_items(crate: &ast::Crate,
     session.abort_if_errors();
     items
 }
+
+// End of the macro
+    }
+}
+
+lets_do_this! {
+    There are 41 lang items.
+
+//  ID, Variant name,                    Name,                      Method name;
+    0,  FreezeTraitLangItem,             "freeze",                  freeze_trait;
+    1,  SendTraitLangItem,               "send",                    send_trait;
+    2,  SizedTraitLangItem,              "sized",                   sized_trait;
+
+    3,  DropTraitLangItem,               "drop",                    drop_trait;
+
+    4,  AddTraitLangItem,                "add",                     add_trait;
+    5,  SubTraitLangItem,                "sub",                     sub_trait;
+    6,  MulTraitLangItem,                "mul",                     mul_trait;
+    7,  DivTraitLangItem,                "div",                     div_trait;
+    8,  RemTraitLangItem,                "rem",                     rem_trait;
+    9,  NegTraitLangItem,                "neg",                     neg_trait;
+    10, NotTraitLangItem,                "not",                     not_trait;
+    11, BitXorTraitLangItem,             "bitxor",                  bitxor_trait;
+    12, BitAndTraitLangItem,             "bitand",                  bitand_trait;
+    13, BitOrTraitLangItem,              "bitor",                   bitor_trait;
+    14, ShlTraitLangItem,                "shl",                     shl_trait;
+    15, ShrTraitLangItem,                "shr",                     shr_trait;
+    16, IndexTraitLangItem,              "index",                   index_trait;
+
+    17, EqTraitLangItem,                 "eq",                      eq_trait;
+    18, OrdTraitLangItem,                "ord",                     ord_trait;
+
+    19, StrEqFnLangItem,                 "str_eq",                  str_eq_fn;
+    20, UniqStrEqFnLangItem,             "uniq_str_eq",             uniq_str_eq_fn;
+    21, FailFnLangItem,                  "fail_",                   fail_fn;
+    22, FailBoundsCheckFnLangItem,       "fail_bounds_check",       fail_bounds_check_fn;
+    23, ExchangeMallocFnLangItem,        "exchange_malloc",         exchange_malloc_fn;
+    24, ClosureExchangeMallocFnLangItem, "closure_exchange_malloc", closure_exchange_malloc_fn;
+    25, ExchangeFreeFnLangItem,          "exchange_free",           exchange_free_fn;
+    26, MallocFnLangItem,                "malloc",                  malloc_fn;
+    27, FreeFnLangItem,                  "free",                    free_fn;
+    28, BorrowAsImmFnLangItem,           "borrow_as_imm",           borrow_as_imm_fn;
+    29, BorrowAsMutFnLangItem,           "borrow_as_mut",           borrow_as_mut_fn;
+    30, ReturnToMutFnLangItem,           "return_to_mut",           return_to_mut_fn;
+    31, CheckNotBorrowedFnLangItem,      "check_not_borrowed",      check_not_borrowed_fn;
+    32, StrDupUniqFnLangItem,            "strdup_uniq",             strdup_uniq_fn;
+    33, RecordBorrowFnLangItem,          "record_borrow",           record_borrow_fn;
+    34, UnrecordBorrowFnLangItem,        "unrecord_borrow",         unrecord_borrow_fn;
+
+    35, StartFnLangItem,                 "start",                   start_fn;
+
+    36, TyDescStructLangItem,            "ty_desc",                 ty_desc;
+    37, TyVisitorTraitLangItem,          "ty_visitor",              ty_visitor;
+    38, OpaqueStructLangItem,            "opaque",                  opaque;
+
+    39, EventLoopFactoryLangItem,        "event_loop_factory",      event_loop_factory;
+
+    40, TypeIdLangItem,                  "type_id",                 type_id;
+}