Rename car/cdr to head/tail in std::list

Closes #1086

src/comp/middle/resolve.rs

@@ -356,11 +356,10 @@ fn visit_block_with_scope(b: ast::blk, sc: scopes, v: vt<scopes>) {
 }
 
 fn visit_decl_with_scope(d: @decl, sc: scopes, v: vt<scopes>) {
-    let loc_pos =
-        alt list::car(sc) {
-          scope_block(_, _, pos) { pos }
-          _ { @mutable 0u }
-        };
+    let loc_pos = alt list::head(sc) {
+      scope_block(_, _, pos) { pos }
+      _ { @mutable 0u }
+    };
     alt d.node {
       decl_local(locs) {
         for (_, loc) in locs { v.visit_local(loc, sc, v);; *loc_pos += 1u; }

src/lib/list.rs

@@ -105,20 +105,20 @@ fn len<T>(ls: list<T>) -> uint {
 }
 
 /*
-Function: cdr
+Function: tail
 
 Returns all but the first element of a list
 */
-fn cdr<T>(ls: list<T>) -> list<T> {
+fn tail<T>(ls: list<T>) -> list<T> {
     alt ls { cons(_, tl) { ret *tl; } nil. { fail "list empty" } }
 }
 
 /*
-Function: car
+Function: head
 
 Returns the first element of a list
 */
-fn car<T>(ls: list<T>) -> T {
+fn head<T>(ls: list<T>) -> T {
     alt ls { cons(hd, _) { ret hd; } nil. { fail "list empty" } }
 }
 

src/test/run-pass/non-boolean-pure-fns.rs

@@ -14,7 +14,7 @@ pure fn nonempty_list<T>(ls: list<T>) -> bool { pure_length(ls) > 0u }
 // knowledge that ls is a cons node. Future work.
 // Also, this is pretty contrived since nonempty_list
 // could be a "tag refinement", if we implement those.
-fn safe_head<T>(ls: list<T>) : nonempty_list(ls) -> T { car(ls) }
+fn safe_head<T>(ls: list<T>) : nonempty_list(ls) -> T { head(ls) }
 
 fn main() {
     let mylist = cons(@1u, @nil);

src/test/run-pass/unchecked-predicates.rs

@@ -22,7 +22,7 @@ pure fn nonempty_list<T>(ls: list<T>) -> bool { pure_length(ls) > 0u }
 // knowledge that ls is a cons node. Future work.
 // Also, this is pretty contrived since nonempty_list
 // could be a "tag refinement", if we implement those.
-fn safe_head<T>(ls: list<T>) : nonempty_list(ls) -> T { car(ls) }
+fn safe_head<T>(ls: list<T>) : nonempty_list(ls) -> T { head(ls) }
 
 fn main() {
     let mylist = cons(@1u, @nil);

src/test/stdtest/list.rs

@@ -1,25 +1,25 @@
 
 use std;
 import std::list;
-import std::list::car;
-import std::list::cdr;
+import std::list::head;
+import std::list::tail;
 import std::list::from_vec;
 import std::option;
 
 #[test]
 fn test_from_vec() {
     let l = from_vec([0, 1, 2]);
-    assert (car(l) == 0);
-    assert (car(cdr(l)) == 1);
-    assert (car(cdr(cdr(l))) == 2);
+    assert (head(l) == 0);
+    assert (head(tail(l)) == 1);
+    assert (head(tail(tail(l))) == 2);
 }
 
 #[test]
 fn test_from_vec_mut() {
     let l = from_vec([mutable 0, 1, 2]);
-    assert (car(l) == 0);
-    assert (car(cdr(l)) == 1);
-    assert (car(cdr(cdr(l))) == 2);
+    assert (head(l) == 0);
+    assert (head(tail(l)) == 1);
+    assert (head(tail(tail(l))) == 2);
 }
 
 #[test]