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authorMichael G. Schwern <schwern@pobox.com>2003-05-13 11:33:05 -0700
committerRafael Garcia-Suarez <rgarciasuarez@gmail.com>2003-07-11 18:54:09 +0000
commit6014d0cb2904bf89033c6aa0d3dbb1d1600d6994 (patch)
tree506b2b283a48cddee7fa8dc08ef97f0f3039b063 /pod/perlsyn.pod
parent103dd89994b01bc194bfaf186624c2fb15f80afe (diff)
downloadperl-6014d0cb2904bf89033c6aa0d3dbb1d1600d6994.tar.gz
New introduction
Message-ID: <20030514013305.GB22001@windhund.schwern.org> p4raw-id: //depot/perl@20154
Diffstat (limited to 'pod/perlsyn.pod')
-rw-r--r--pod/perlsyn.pod44
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diff --git a/pod/perlsyn.pod b/pod/perlsyn.pod
index 5ddd7e1d45..9aec074dd1 100644
--- a/pod/perlsyn.pod
+++ b/pod/perlsyn.pod
@@ -4,23 +4,27 @@ perlsyn - Perl syntax
=head1 DESCRIPTION
-A Perl script consists of a sequence of declarations and statements.
-The sequence of statements is executed just once, unlike in B<sed>
-and B<awk> scripts, where the sequence of statements is executed
-for each input line. While this means that you must explicitly
-loop over the lines of your input file (or files), it also means
-you have much more control over which files and which lines you look at.
-(Actually, I'm lying--it is possible to do an implicit loop with
-either the B<-n> or B<-p> switch. It's just not the mandatory
-default like it is in B<sed> and B<awk>.)
-
-Perl is, for the most part, a free-form language. (The only exception
-to this is format declarations, for obvious reasons.) Text from a
-C<"#"> character until the end of the line is a comment, and is
-ignored. If you attempt to use C</* */> C-style comments, it will be
-interpreted either as division or pattern matching, depending on the
-context, and C++ C<//> comments just look like a null regular
-expression or defined-or operator, so don't do that.
+A Perl program consists of a sequence of declarations and statements
+which run from the top to the bottom. Loops, subroutines and other
+control structures allow you to jump around within the code.
+
+Perl is a B<free-form> language, you can format and indent it however
+you like. Whitespace mostly serves to separate tokens, unlike
+languages like Python where it is an important part of the syntax.
+
+Many of Perl's syntactic elements are B<optional>. Rather than
+requiring you to put parenthesis around every function call and
+declare every variable, you can often leave such explicit elements off
+and Perl will figure out what you meant. This is known as B<Do What I
+Mean>, abbreviated B<DWIM>. It allows programmers to be B<lazy> and to
+code in a style which they are comfortable.
+
+Perl B<borrows syntax> and concepts from many languages: awk, sed, C,
+Bourne Shell, Smalltalk, Lisp and even English. Other
+languages have borrowed syntax from Perl, particularly its regular
+expression extensions. So if you have programmed in another language
+you will see familiar pieces in Perl. They often work the same, but
+see L<perltrap> for information about how they differ.
=head2 Declarations
@@ -79,6 +83,12 @@ like an ordinary statement, and is elaborated within the sequence of
statements as if it were an ordinary statement. That means it actually
has both compile-time and run-time effects.
+=head2 Comments
+
+Text from a C<"#"> character until the end of the line is a comment,
+and is ignored. Exceptions include C<"#"> inside a string or regular
+expression.
+
=head2 Simple Statements
The only kind of simple statement is an expression evaluated for its