Re: tracing cosmetics

[Per Bothner <per at bothner dot com>]

Per Bothner <per@bothner.com> writes:
> (3) Instead of using a static field, one should use a static
> Binding field, with a FluidConstraint and a per-thread FluidBinding.
> That may be a little hairy to figure out, that it has the advantage
> of being a local change.

I implemented this.

1999-10-07  Per Bothner  <per@bothner.com>

	* kawa/standard/TracedProcedure.java:  Indent nested calls.

Index: TracedProcedure.java
===================================================================
RCS file: /cvs/kawa/kawa/kawa/standard/TracedProcedure.java,v
retrieving revision 1.1
diff -u -r1.1 TracedProcedure.java
--- TracedProcedure.java	1999/07/20 01:59:36	1.1
+++ TracedProcedure.java	1999/10/08 05:23:57
@@ -1,6 +1,7 @@
 package kawa.standard;
 import gnu.mapping.*;
 import java.io.PrintWriter;
+import gnu.math.IntNum;
 
 /** A TracedProcedure is a Procedure wrapper that writes trace output. */
 
@@ -9,6 +10,10 @@
   public Procedure proc;
   boolean enabled;
 
+  static Binding indentation
+  = Binding.make(gnu.math.IntNum.zero(), "indentation");
+  static int indentationStep = 2;
+
   public TracedProcedure (Procedure proc, boolean enable)
   {
     this.proc = proc;
@@ -33,14 +38,24 @@
       }
   }
 
+  static void indent(int i, PrintWriter out)
+  {
+    while (--i >= 0)
+      out.print(' ');
+  }
+
   public Object applyN(Object[] args)
   {
     if (enabled)
       {
+        int curIndent = ((IntNum) indentation.getValue()).intValue();
 	PrintWriter out = OutPort.errDefault();
 	String name = getName();
 	if (name == null)
 	  name = "??";
+
+        // Print the call arguments (indented).
+        indent(curIndent, out);
 	out.print("call to ");
 	out.print(name);
 	int len = args.length;
@@ -52,7 +67,26 @@
 	    put(args[i], out);
 	  }
 	out.println(")");
-	Object result = proc.applyN(args);
+
+        // Now do the actual call, but with the indentation incremented.
+        gnu.mapping.Future context = gnu.mapping.Future.getContext();
+        FluidBinding oldBindings = context.fluidBindings;
+        IntNum newIndentation = IntNum.make(curIndent+indentationStep);
+        FluidBinding newBindings
+          = new FluidBinding(oldBindings, newIndentation, indentation);
+	Object result;
+        try
+          {
+            context.setFluids(newBindings);
+            result = proc.applyN(args);
+          }
+        finally
+          {
+            context.resetFluids(oldBindings);
+          }
+
+        // Print the result (indented).
+        indent(curIndent, out);
 	out.print("return from ");
 	out.print(name);
 	out.print(" => ");

Sample output:

#|kawa:1|# (define (fac x) (if (> x 1) (* x (fac (- x 1))) 1))
#|kawa:2|# (fac 4)
24
#|kawa:3|# (trace fac)
#|kawa:4|# (fac 4)
call to fac (4)
  call to fac (3)
    call to fac (2)
      call to fac (1)
      return from fac => 1
    return from fac => 2
  return from fac => 6
return from fac => 24
24
-- 
	--Per Bothner
bothner@pacbell.net  per@bothner.com   http://www.bothner.com/~per/