smalltalk: SequenceableCollection methods (13) + String at:/copyFrom:to: + 28 tests

lib/smalltalk/eval.sx

@@ -757,6 +757,25 @@
       ((= selector "printString") (str "'" s "'"))
       ((= selector "asString") s)
       ((= selector "asSymbol") (make-symbol (if (symbol? s) (str s) s)))
+      ;; 1-indexed character access; returns the character (a 1-char string).
+      ((= selector "at:") (nth s (- (nth args 0) 1)))
+      ((= selector "do:")
+        (let ((i 0) (n (len s)) (block (nth args 0)))
+          (begin
+            (define
+              sd-loop
+              (fn ()
+                (when (< i n)
+                  (begin
+                    (st-block-apply block (list (nth s i)))
+                    (set! i (+ i 1))
+                    (sd-loop)))))
+            (sd-loop)
+            s)))
+      ((= selector "first") (nth s 0))
+      ((= selector "last") (nth s (- (len s) 1)))
+      ((= selector "copyFrom:to:")
+        (slice s (- (nth args 0) 1) (nth args 1)))
       ((= selector "class") (st-class-ref (st-class-of s)))
       ((= selector "isNil") false)
       ((= selector "notNil") true)