cons man page: new convention for undefined vars.

1 files changed, 13 insertions, 7 deletions

diff --git a/cppawk-cons.1 b/cppawk-cons.1
index 3d97e7b..dcf413f 100644
--- a/cppawk-cons.1
+++ b/cppawk-cons.1
@@ -456,6 +456,14 @@ denote that the expression
 returns the value
 .IR Y ,
 
+In examples, whenever a variable appears with one of the names
+.IR undef ,
+.I undef1
+or
+.IR undef2 ,
+it is to be understood as a variable that was not assigned, and
+therefore evaluates to the undefined value.
+
 The
 .B =>
 notation indicates that
@@ -688,7 +696,7 @@ symbol, and not as \f"B"Snil"\fP.
   box(0.707) => 0.707
   box("") => "T"
   box("abc") => "Tabc"
-  box(undefined_var) => "U"
+  box(undef) => "U"
 
   unbox(nil) => "nil"         // name of symbol nil is "nil"
   unbox(box("abc")) => "abc"
@@ -758,17 +766,15 @@ symbol as an argument instead of a cons, in which case they return
   car(cons(1, 2)) -> 1
   cdr(cons(1, "abc")) => "abc"
 
-  // Below, abc and def are assumed to be unassigned.
-
   // Without boxing, undefined gets treated as nil.
 
-  cons(abc, def) => "C0,0:" -> (nil . nil)
-  car(cons(abc, def)) => "" -> nil
+  cons(undef1, undef2) => "C0,0:" -> (nil . nil)
+  car(cons(undef1, undef2)) => "" -> nil
 
   // Boxing passes through and recovers Awk undefined value
 
-  cons(box(abc), box(def)) => "C1,1:UU" -> (#U . #U)
-  car(cons(box(abc), box(def))) => ;; Awk undefined value
+  cons(box(undef1), box(undef2)) => "C1,1:UU" -> (#U . #U)
+  car(cons(box(undef1), box(undef1))) => ;; Awk undefined value
 .ft R
 
 .SS Function \fIsexp\fP