aboutsummaryrefslogtreecommitdiff
path: root/src/lib/Option.rs
diff options
context:
space:
mode:
authorMarijn Haverbeke <[email protected]>2011-05-06 22:13:13 +0200
committerMarijn Haverbeke <[email protected]>2011-05-06 22:51:19 +0200
commita3ec0b1f643d00b9418e4884bd7caa07bf052201 (patch)
tree82000510ac9c9cf3f0c7cf4ae5f3c6b123b559cb /src/lib/Option.rs
parentRegister new snapshots. (diff)
downloadrust-a3ec0b1f643d00b9418e4884bd7caa07bf052201.tar.xz
rust-a3ec0b1f643d00b9418e4884bd7caa07bf052201.zip
Rename std modules to be camelcased
(Have fun mergining your stuff with this.)
Diffstat (limited to 'src/lib/Option.rs')
-rw-r--r--src/lib/Option.rs60
1 files changed, 60 insertions, 0 deletions
diff --git a/src/lib/Option.rs b/src/lib/Option.rs
new file mode 100644
index 00000000..3fb9aa3b
--- /dev/null
+++ b/src/lib/Option.rs
@@ -0,0 +1,60 @@
+// lib/Option.rs
+
+tag t[T] {
+ none;
+ some(T);
+}
+
+type operator[T, U] = fn(&T) -> U;
+
+fn get[T](&t[T] opt) -> T {
+ alt (opt) {
+ case (some[T](?x)) {
+ ret x;
+ }
+ case (none[T]) {
+ fail;
+ }
+ }
+ fail; // FIXME: remove me when exhaustiveness checking works
+}
+
+fn map[T, U](&operator[T, U] f, &t[T] opt) -> t[U] {
+ alt (opt) {
+ case (some[T](?x)) {
+ ret some[U](f(x));
+ }
+ case (none[T]) {
+ ret none[U];
+ }
+ }
+ fail; // FIXME: remove me when exhaustiveness checking works
+}
+
+fn is_none[T](&t[T] opt) -> bool {
+ alt (opt) {
+ case (none[T]) { ret true; }
+ case (some[T](_)) { ret false; }
+ }
+}
+
+fn from_maybe[T](&T def, &t[T] opt) -> T {
+ auto f = bind Util.id[T](_);
+ ret maybe[T, T](def, f, opt);
+}
+
+fn maybe[T, U](&U def, fn(&T) -> U f, &t[T] opt) -> U {
+ alt (opt) {
+ case (none[T]) { ret def; }
+ case (some[T](?t)) { ret f(t); }
+ }
+}
+// Local Variables:
+// mode: rust;
+// fill-column: 78;
+// indent-tabs-mode: nil
+// c-basic-offset: 4
+// buffer-file-coding-system: utf-8-unix
+// compile-command: "make -k -C .. 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
+// End:
+