summaryrefslogtreecommitdiff
path: root/src/search.sml
diff options
context:
space:
mode:
Diffstat (limited to 'src/search.sml')
-rw-r--r--src/search.sml70
1 files changed, 70 insertions, 0 deletions
diff --git a/src/search.sml b/src/search.sml
new file mode 100644
index 00000000..50904bba
--- /dev/null
+++ b/src/search.sml
@@ -0,0 +1,70 @@
+(* Copyright (c) 2008, Adam Chlipala
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * - The names of contributors may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *)
+
+structure Search :> SEARCH = struct
+
+datatype ('state, 'abort) result =
+ Return of 'abort
+ | Continue of 'state
+
+type ('data, 'state, 'abort) mapfold_arg =
+ 'data * 'state -> ('data * 'state, 'abort) result
+
+type ('data, 'state, 'abort) mapfolder =
+ 'data -> 'state -> ('data * 'state, 'abort) result
+
+fun return2 v acc = Continue (v, acc)
+
+fun map (r, f) =
+ case r of
+ Continue acc => Continue (f acc)
+ | Return x => Return x
+
+fun map2 (r, f) acc =
+ case r acc of
+ Continue (x, acc) => Continue (f x, acc)
+ | Return x => Return x
+
+fun bind (r, f) =
+ case r of
+ Continue acc => f acc
+ | Return x => Return x
+
+fun bind2 (r, f) acc =
+ case r acc of
+ Continue (x, acc) => f x acc
+ | Return x => Return x
+
+fun bindP (r, f) =
+ case r of
+ Continue ((x, pos), acc) =>
+ map (f (x, acc),
+ fn (x', acc') =>
+ ((x', pos), acc'))
+ | Return x => Return x
+
+end