add skeleton for instruction constructors

internal/gen/constructors_test.go

@@ -0,0 +1,28 @@
+package gen
+
+import (
+	"testing"
+
+	"github.com/mmcloughlin/avo/internal/inst"
+)
+
+func TestParamsUniqueArgNames(t *testing.T) {
+	for _, i := range inst.Instructions {
+		_, argname := params(i)
+		for _, n := range i.Arities() {
+			if n == 0 {
+				continue
+			}
+			names := map[string]bool{}
+			for j := 0; j < n; j++ {
+				names[argname(j)] = true
+			}
+			if len(names) != n {
+				t.Errorf("repeated argument for instruction %s", i.Opcode)
+			}
+			if _, found := names[""]; found {
+				t.Errorf("empty argument name for instruction %s", i.Opcode)
+			}
+		}
+	}
+}