grade-school guidance

exercises/practice/grade-school/.docs/instructions.append.md

@@ -0,0 +1,16 @@
+# Instructions append
+
+## Words
+
+Define a `school` tuple to hold the roster — how you store the
+students inside it is up to you — then implement the words below.
+
+- `<school> ( -- school )` — construct an empty school.
+- `add-student ( school name grade -- ? )` — add `name` to
+  `grade`. Return `t` on success, or `f` if `name` has already
+  been added (to this or any other grade), in which case the
+  roster is left unchanged.
+- `roster ( school -- names )` — all students, sorted by grade
+  and then alphabetically by name.
+- `grade ( school n -- names )` — the students in grade `n`,
+  sorted alphabetically by name.

exercises/practice/grade-school/grade-school/grade-school.factor

@@ -1,7 +1,8 @@
 USING: kernel ;
 IN: grade-school
 
-TUPLE: school students ;
+! Define a `school` tuple to hold the roster, then implement the
+! words below.
 
 : <school> ( -- school )
     "unimplemented" throw ;