Merge pull request #31 from typst-community/28-make-tuple-fail-gracef…

…ully-for-wrong-number-of-values

Error properly on tuple length mismatch

CHANGELOG.md

@@ -11,6 +11,7 @@
 - Added schema generator for argument sinks. Takes `positional` and `named` as optional parameters that take schema types. Absence of one of these parameters indicate that these must also be absent from the argument type being validated.
 - **(Potentially Breaking)** Content now accepts `symbol` as a valid input type by default (see #20)
 - **(Potentially Breaking)** If the tested value is `auto`, parsing no longer fails. If `default` is set, it takes the default value. If `optional` is set but not `default`, value is parsed as `none`.
+- **(Potentially Breaking)** `tuple` has a new parameter `exact` which defaults to true, whereby the length of a tuple must match exactly to be valid.
 
 ---
 

src/types/tuple.typ

@@ -5,9 +5,11 @@
 
 /// Valkyrie schema generator for an array type with positional type reqruiements. If all entries
 /// have the same type, see @@array.
+/// exact (bool): Requires a tuple to match in length
 ///
 /// -> schema
 #let tuple(
+  exact: true,
   ..args,
 ) = {
   assert-base-type-array(args.pos())
@@ -17,8 +19,14 @@
     types: (type(()),),
     ..args.named(),
   ) + (
+    tuple-exact: exact,
     tuple-schema: args.pos(),
     handle-descendents: (self, it, ctx: z-ctx(), scope: ()) => {
+      if (self.tuple-exact and self.tuple-schema.len() != it.len()){
+        (self.fail-validation)(self, it, ctx: ctx, scope: scope, 
+          message: "Expected " + str(self.tuple-schema.len())  + " values, but got " + str(it.len())
+        )
+      }
       for (key, schema) in self.tuple-schema.enumerate() {
         it.at(key) = (schema.validate)(
           schema,