After REPI and WHILEI, the loop variable contains the number of itera…

…tions.

As pointed out by Per Austrin, the value of the loop variable after
the loop was undefined. Define it to be the number of iterations,
i.e. one beyond the last iteration value. Also add a modified test
case provided by Per in #7.

doc/format-spec.md

@@ -153,15 +153,17 @@ The following commands are available:
     times and optionally match 'separator' command (count-1) times in
     between. The value of count must fit in an unsigned 32 bit int.
     The second command 'REPI' does the same, but also stores the
-    current iteration (counting from zero) in the variable 'i'.</dd>
+    current iteration (counting from zero) in the variable 'i'. At the
+    end of the loop, 'i' contains the number of iterations.</dd>
 
 <dt><tt>WHILE(&lt;test&gt; condition [,&lt;command&gt; separator]) [&lt;command&gt;...] END</tt></dt>
 <dt><tt>WHILEI(&lt;variable&gt; i, &lt;test&gt; condition [,&lt;command&gt; separator]) [&lt;command&gt;...] END</tt></dt>
 
 <dd>Repeat the commands as long as 'condition' is true. Optionally
     match 'separator' command between two consecutive iterations.
     The second command 'WHILEI' does the same, but also stores the
-    current iteration (counting from zero) in the variable 'i'.</dd>
+    current iteration (counting from zero) in the variable 'i'. At the
+    end of the loop, 'i' contains the number of iterations.</dd>
 
 <dt><tt>IF(&lt;test&gt; cond) [&lt;command&gt; cmds1...] [ELSE [&lt;command&gt; cmds2...]] END</tt></dt>
 

tests/testdataloopvar.in

@@ -0,0 +1 @@
+0 1

tests/testprogloopvar.in

@@ -0,0 +1,10 @@
+# IGNORE GENERATE TESTING
+# Read exactly 2 bits (space-separated)
+WHILEI(i,!MATCH("\n"), SPACE)
+  INT(0,1)
+END
+ASSERT(i==2)
+NEWLINE
+# Test an empty loop
+REPI(j,0) END
+ASSERT(j==0)