X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlsyn.pod;h=5d25a77f5c7a63d2c897adc36a7da98d695a5698;hb=f26f4a2f8b63c72a33468ddeeb9d0337f0892af6;hp=80df487622b2ae277845e44745c1b03014ee4281;hpb=cf48932e9c614884be015feecb615c4d42f6f135;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/pod/perlsyn.pod b/pod/perlsyn.pod
index 80df487..5d25a77 100644
--- a/pod/perlsyn.pod
+++ b/pod/perlsyn.pod
@@ -94,8 +94,8 @@ expression.
 The only kind of simple statement is an expression evaluated for its
 side effects.  Every simple statement must be terminated with a
 semicolon, unless it is the final statement in a block, in which case
-the semicolon is optional.  (A semicolon is still encouraged there if
-the block takes up more than one line, because you may eventually add
+the semicolon is optional.  (A semicolon is still encouraged if the
+block takes up more than one line, because you may eventually add
 another line.)  Note that there are some operators like C<eval {}> and
 C<do {}> that look like compound statements, but aren't (they're just
 TERMs in an expression), and thus need an explicit termination if used
@@ -103,12 +103,11 @@ as the last item in a statement.
 
 =head2 Truth and Falsehood
 
-A false value is C<undef>, the number 0, the string C<'0'> and the
-empty string C<''>.  Note that unlike some languages, these are three
-distinctly different values.  A true value is everything which is not
-false.
-
-Note that while 0, 0.0 and C<'0'> are false, C<'0.0'> is true.
+The number 0, the strings C<'0'> and C<''>, the empty list C<()>, and
+C<undef> are all false in a boolean context. All other values are true.
+Negation of a true value by C<!> or C<not> returns a special false value.
+When evaluated as a string it is treated as C<''>, but as a number, it
+is treated as 0.
 
 =head2 Statement Modifiers
 
@@ -200,6 +199,8 @@ The following compound statements may be used to control flow:
     if (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK
     LABEL while (EXPR) BLOCK
     LABEL while (EXPR) BLOCK continue BLOCK
+    LABEL until (EXPR) BLOCK
+    LABEL until (EXPR) BLOCK continue BLOCK
     LABEL for (EXPR; EXPR; EXPR) BLOCK
     LABEL foreach VAR (LIST) BLOCK
     LABEL foreach VAR (LIST) BLOCK continue BLOCK
@@ -224,6 +225,8 @@ the sense of the test is reversed.
 
 The C<while> statement executes the block as long as the expression is
 true (does not evaluate to the null string C<""> or C<0> or C<"0">).
+The C<until> statement executes the block as long as the expression is
+false.
 The LABEL is optional, and if present, consists of an identifier followed
 by a colon.  The LABEL identifies the loop for the loop control
 statements C<next>, C<last>, and C<redo>.