From 183f3858c4d20d363329340af0f1f4b055fb1f39 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Mon, 27 Mar 2023 20:22:23 -0400
Subject: repl: Add multiple return value support.

---
 catbird/repl.scm | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/catbird/repl.scm b/catbird/repl.scm
index d3768b5..3c56f35 100644
--- a/catbird/repl.scm
+++ b/catbird/repl.scm
@@ -42,12 +42,13 @@
   #:use-module (srfi srfi-9)
   #:use-module (system base compile)
   #:use-module (system base language)
+  #:use-module (system vm loader)
   #:export (<repl>
             <repl-mode>
             resize-repl
             repl-print))
 
-;; TODO: Multiple values
+;; TODO: $number values like regular Guile REPL
 ;; TODO: Multiple expressions
 ;; TODO: Debugger
 ;; TODO: Switching languages
@@ -174,17 +175,15 @@
       ((language-reader (language repl)) port (module repl)))))
 
 (define-method (with-output-to-log (repl <repl>) thunk)
-  (let* ((val *unspecified*)
+  (let* ((vals #f)
          (str (call-with-output-string
                 (lambda (port)
                   (parameterize ((current-output-port port)
                                  (current-error-port port))
-                    (set! val (thunk)))))))
+                    (set! vals (call-with-values thunk list)))))))
     (unless (string-null? str)
-      (for-each (lambda (line)
-                  (log-append repl line))
-                (string-split str #\newline)))
-    val))
+      (log-append repl str))
+    (apply values vals)))
 
 (define-method (with-error-handling (repl <repl>) thunk)
   (let ((stack #f))
@@ -227,17 +226,22 @@
     (with-exception-handler exception-handler throw-handler #:unwind? #t)))
 
 (define-method (repl-compile (repl <repl>) line)
+  (define thunk
+    (load-thunk-from-memory
+     (compile (repl-read-expression repl line)
+              #:from (language repl)
+              #:to 'bytecode
+              #:env (module repl))))
   (define (compile-line)
-    (with-output-to-log repl
-                        (lambda ()
-                          (compile (repl-read-expression repl line)
-                                   #:from (language repl)
-                                   #:env (module repl)))))
+    (with-output-to-log repl thunk))
   (with-error-handling repl compile-line))
 
 (define-method (write-value-to-log (repl <repl>) x)
   (unless (unspecified? x)
-    (log-append repl (repl-print x))))
+    (log-append repl (make <horizontal-container>
+                       #:children
+                       (list (make <label> #:text "=> ")
+                             (repl-print x))))))
 
 (define (skip-whitespace str i)
   (let loop ((i i))
@@ -296,7 +300,9 @@
     (log-append repl (string-append (prompt editor) line))
     (if (meta-command-string? line)
         (meta-command repl line)
-        (write-value-to-log repl (repl-compile repl line)))
+        (for-each (lambda (val)
+                    (write-value-to-log repl val))
+                  (call-with-values (lambda () (repl-compile repl line)) list)))
     (clear-line editor)
     (refresh-log repl)
     (refresh-prompt repl)))
-- 
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