Add stack depth arg validation for make_sb_tree example word

Aaron K. Johnson · Aaron K. Johnson · commit deb747eb4968 · 2025-03-22T14:31:54.000-07:00
diff --git a/examples/stern_brocot_tree.dc b/examples/stern_brocot_tree.dc
@@ -42,7 +42,12 @@ lmake denominators !
   again
 ;
 
-: make_sb_tree { loops n1 d1 n2 d2 }
+: make_sb_tree
+    depth 5 < if
+      "make_sb_tree: stack underflow; need <loops> <n1> <d1> <n2> <d2> on the stack!" print cr
+      return
+    endif
+    { loops n1 d1 n2 d2 }
     0 loops n1 d1 n2 d2 _make_sb_tree_real
   _show_sb_tree
 ;

Original file line number	Diff line number	Diff line change
`@@ -42,7 +42,12 @@ lmake denominators !`
`42`	`42`	`again`
`43`	`43`	`;`
`44`	`44`
`45`		`-: make_sb_tree { loops n1 d1 n2 d2 }`
	`45`	`+: make_sb_tree`
	`46`	`+ depth 5 < if`
	`47`	`+ "make_sb_tree: stack underflow; need <loops> <n1> <d1> <n2> <d2> on the stack!" print cr`
	`48`	`+ return`
	`49`	`+ endif`
	`50`	`+ { loops n1 d1 n2 d2 }`
`46`	`51`	`0 loops n1 d1 n2 d2 _make_sb_tree_real`
`47`	`52`	`_show_sb_tree`
`48`	`53`	`;`