ok, added inavid_operator_args and associated stuff

Common/src/main/java/at/petrak/hexcasting/api/casting/castables/OperationAction.kt

@@ -18,7 +18,7 @@ data class OperationAction(val pattern: HexPattern) : Action {
         return try {
             HexArithmetics.getEngine().run(pattern, env, image, continuation)
         } catch (e: NoOperatorCandidatesException) {
-            throw MishapInvalidOperatorArgs(e.args, e.pattern)
+            throw MishapInvalidOperatorArgs(e.args)
         }
     }
 }

Common/src/main/java/at/petrak/hexcasting/api/casting/mishaps/MishapInvalidOperatorArgs.kt

@@ -0,0 +1,54 @@
+package at.petrak.hexcasting.api.casting.mishaps
+
+import at.petrak.hexcasting.api.casting.eval.CastingEnvironment
+import at.petrak.hexcasting.api.casting.iota.GarbageIota
+import at.petrak.hexcasting.api.casting.iota.Iota
+import at.petrak.hexcasting.api.pigment.FrozenPigment
+import net.minecraft.network.chat.Component
+import net.minecraft.network.chat.ComponentContents
+import net.minecraft.network.chat.MutableComponent
+import net.minecraft.world.item.DyeColor
+
+/**
+ * The value failed some kind of predicate.
+ */
+class MishapInvalidOperatorArgs(
+    private val perpetrators: List<Iota>
+) : Mishap() {
+    override fun accentColor(ctx: CastingEnvironment, errorCtx: Context): FrozenPigment =
+        dyeColor(DyeColor.GRAY)
+
+    override fun execute(env: CastingEnvironment, errorCtx: Context, stack: MutableList<Iota>) {
+        for (i in perpetrators.indices) {
+            stack[stack.size - 1 - i] = GarbageIota()
+        }
+    }
+
+    override fun errorMessage(ctx: CastingEnvironment, errorCtx: Context): Component {
+        return if (perpetrators.size == 1) {
+            error(
+                "invalid_operator_args.single",
+                0,
+                perpetrators[0].display()
+            )
+        } else {
+            error(
+                "invalid_operator_args.plural",
+                perpetrators.size,
+                0,
+                perpetrators.lastIndex,
+                collateIotas(perpetrators)
+            )
+        }
+    }
+    private fun collateIotas(iotas: List<Iota>): MutableComponent {
+        val out = MutableComponent.create(ComponentContents.EMPTY)
+        for (i in iotas.indices) {
+            out.append(iotas[i].display())
+            if (i < iotas.size-1) {
+                out.append(", ")
+            }
+        }
+        return out
+    }
+}

Common/src/main/resources/assets/hexcasting/lang/en_us.flatten.json5

@@ -890,6 +890,11 @@
         cos: "the cosine of %s",
       },
 
+      invalid_operator_args: {
+        single: "Got an unexpected iota at index %d of the stack: %s",
+        plural: "Got %d unexpected iotas at indices %d-%d of the stack: %s",
+      },
+
       no_akashic_record: "No Akashic Record at %s",
       disallowed: "has been disallowed by the server admins",
       disallowed_circle: "has been disallowed in spell circles by the server admins",