BSD 4_3 development

Work on file usr/contrib/icon/book/19/fix.icn

Synthesized-from: CSRG/cd1/4.3

diff --git a/usr/contrib/icon/book/19/fix.icn b/usr/contrib/icon/book/19/fix.icn
new file mode 100644 (file)
index 0000000..faf63e5
--- /dev/null
+++ b/usr/contrib/icon/book/19/fix.icn
@@ -0,0 +1,24 @@
+procedure main()
+   while write(fix(read()))
+end
+
+procedure fix(exp)
+   while exp ?:= 2(="(",tab(bal(')')),pos(-1))
+   return lassoc(exp,'+-' | '*/') | rassoc(exp,'^') | exp
+end
+
+procedure lassoc(exp,op)
+   local j
+   return exp ? {
+      every j := bal(op)
+      form(tab(\j),move(1),tab(0))
+      }
+end
+
+procedure rassoc(exp,op)
+   return exp ? form(tab(bal(op)),move(1),tab(0))
+end
+
+procedure form(arg1,op,arg2)
+   return op || "(" || fix(arg1) || "," || fix(arg2) || ")"
+end