log serial io to _G.modem-spew instead of stdout

sms.fnl

@@ -23,9 +23,14 @@
 (fn escape-readably [s]
   (s:gsub "%c" (fn [x] (string.format "\\u{%.3x}"  (string.byte x)))))
 
+(fn log-xfer [direction message]
+  (when _G.modem-spew
+    (_G.modem-spew:write direction " " (escape-readably message) "\n"))
+  message)
+
 (fn tx [fd s]
   (write fd s)
-  (print (.. ">>> " (escape-readably s)))
+  (log-xfer :>>> s)
   (nanosleep {:tv_sec 0 :tv_nsec (* 10 1000 1000)}))
 
 (fn chars [i]
@@ -47,15 +52,15 @@
 (fn expect [fd pattern fail-pattern]
   (let [b (read fd 1024)]
     (if (> (# b) 0)
-        (do
-          (print (.. "<<< " (escape-readably b)))
-          (if (string.find b pattern)
-              (do (print "found" pattern) true)
-              (and fail-pattern (string.find b fail-pattern))
-              (error (.. "Expected " pattern ", got " (escape-readably b)))
-              (expect fd pattern)))
+        (if (string.find (log-xfer :<<< b) pattern)
+            (log-xfer :!!! pattern)
+            (and fail-pattern (string.find b fail-pattern))
+            (error (.. "Expected " pattern ", got " (escape-readably b)))
+            (expect fd pattern fail-pattern))
         nil)))
 
+
+
 (fn even? [x]
   (= (% x 2) 0))