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perldata.pod corrections

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From:
Shlomi Fish
Date:
May 14, 2003 01:08
Subject:
perldata.pod corrections
Message ID:
Pine.LNX.4.33L2.0305141104330.18322-200000@vipe.technion.ac.il
--- orig/perldata.pod	Mon May 12 17:51:14 2003
+++ pod/perldata.pod	Wed May 14 11:03:00 2003
@@ -7,10 +7,14 @@
 =head2 Variable names
 
 Perl has three built-in data types: scalars, arrays of scalars, and
-associative arrays of scalars, known as "hashes".  Normal arrays
-are ordered lists of scalars indexed by number, starting with 0 and with
-negative subscripts counting from the end.  Hashes are unordered
-collections of scalar values indexed by their associated string key.
+associative arrays of scalars, known as "hashes".  A scalar is a 
+single string (of any size, limited only by the available memory),
+number, or reference to something (which will be further discussed
+in L<perlref>).  Normal arrays are ordered lists of scalars indexed
+by number, starting with 0. When a negative subscript is supplied
+to an array, it retrieves that index from the end of the array.
+Hashes are unordered collections of scalar values indexed by
+their associated string key.
 
 Values are usually referred to by name, or through a named reference.
 The first character of the name tells you to what sort of data
@@ -187,10 +191,11 @@
 
 To find out whether a given string is a valid non-zero number, it's
 sometimes enough to test it against both numeric 0 and also lexical
-"0" (although this will cause B<-w> noises).  That's because strings
-that aren't numbers count as 0, just as they do in B<awk>:
+"0" (although this will cause noises if extra warnings were turned on
+in the interpreter).  That's because strings that aren't numbers count 
+as 0, just as they do in B<awk>:
 
-    if ($str == 0 && $str ne "0")  {
+    if (($str == 0) && ($str ne "0"))  {
 	warn "That doesn't look like a number";
     }
 
@@ -312,6 +317,8 @@
     $Price = '$100';	# not interpreted
     print "The price is $Price.\n";	# interpreted
 
+As you see, there is no double interpolation in Perl.
+
 As in some shells, you can enclose the variable name in braces to
 disambiguate it from following alphanumerics (and underscores).
 You must also do
@@ -335,6 +342,8 @@
 anything more complicated in the subscript will be interpreted as
 an expression.
 
+=head3 Version Strings
+
 A literal of the form C<v1.20.300.4000> is parsed as a string composed
 of characters with the specified ordinals.  This form, known as
 v-strings, provides an alternative, more readable way to construct
@@ -354,6 +363,8 @@
 Note that using the v-strings for IPv4 addresses is not portable unless
 you also use the inet_aton()/inet_ntoa() routines of the Socket package.
 
+=head3 Meta Literals
+
 The special literals __FILE__, __LINE__, and __PACKAGE__
 represent the current filename, line number, and package name at that
 point in your program.  They may be used only as separate tokens; they
@@ -381,6 +392,8 @@
 as it is seen (during compilation), at which point the corresponding
 __DATA__ (or __END__) token has not yet been seen.
 
+=head3 Barewords
+
 A word that has no other interpretation in the grammar will
 be treated as if it were a quoted string.  These are known as
 "barewords".  As with filehandles and labels, a bareword that consists
@@ -397,10 +410,12 @@
 end of the enclosing block.  An inner block may countermand this
 by saying C<no strict 'subs'>.
 
+=head3 Array Joining Delimiter
+
 Arrays and slices are interpolated into double-quoted strings
 by joining the elements with the delimiter specified in the C<$">
-variable (C<$LIST_SEPARATOR> in English), space by default.  The
-following are equivalent:
+variable (C<$LIST_SEPARATOR> if the "use English;" pragma is
+specified), space by default.  The following are equivalent:
 
     $temp = join($", @ARGV);
     system "echo $temp";

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