From 6321828006394266ccdbf21d13678b1674cfe519 Mon Sep 17 00:00:00 2001
From: Jeremy Wall <jeremy@marzhillstudios.com>
Date: Sun, 20 Jan 2019 08:32:05 -0600
Subject: [PATCH] FEATURE: The begnnings of some schema definition utilities.

Also allow failure messages to be generated from any expression.
---
 src/parse/mod.rs          |  2 +-
 std/schema.ucg            | 15 +++++++++++++++
 std/tests/schema_test.ucg | 12 ++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 std/schema.ucg
 create mode 100644 std/tests/schema_test.ucg

diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index 3febdbc..2add3aa 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -663,7 +663,7 @@ make_fn!(
     do_each!(
         pos => pos,
         _ => word!("fail"),
-        msg => must!(wrap_err!(either!(format_expression, string_expression), "Expected failure message")),
+        msg => must!(wrap_err!(expression, "Expected failure message")),
         (Expression::Fail(FailDef{
             pos: pos,
             message: Box::new(msg),
diff --git a/std/schema.ucg b/std/schema.ucg
new file mode 100644
index 0000000..d6a1bad
--- /dev/null
+++ b/std/schema.ucg
@@ -0,0 +1,15 @@
+let one_of = module {
+    val=NULL,
+    types=[],
+} => {
+    let reducer = macro(acc, t) => acc{
+        ok = acc.ok || (acc.val is t),
+    };
+    let any = macro(val, types) => reduce reducer {ok=false, val=val}, types;
+
+    let result = any(mod.val, mod.types).ok;
+};
+
+let must = macro(m, msg) => select m.result, fail msg, {
+    true = m.result,
+};
diff --git a/std/tests/schema_test.ucg b/std/tests/schema_test.ucg
new file mode 100644
index 0000000..4a9676d
--- /dev/null
+++ b/std/tests/schema_test.ucg
@@ -0,0 +1,12 @@
+let t = import "std/testing.ucg".asserts{};
+let schema = import "std/schema.ucg";
+
+assert t.ok{
+    test = schema.must(schema.one_of{val=1, types=["float", "int"]}, "Must be a float or an int"),
+    desc = "1 is an int",
+};
+
+assert t.not_ok{
+    test = schema.one_of{val=1, types=["float", "str"]}.result,
+    desc = "1 is not a float or string",
+};
\ No newline at end of file