X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlstyle.pod;h=bfe5b767135ad6e3352b6e019a6ce304436021cf;hb=0fd3e83781d94dc1f84f1fcb8cce89958518b5e8;hp=734b9ad03272bfb4e1970b5c8a8f2dc9a0c4524f;hpb=0135f10892ed8a21c4dbd1fca21fbcc365df99dd;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlstyle.pod b/pod/perlstyle.pod index 734b9ad..bfe5b76 100644 --- a/pod/perlstyle.pod +++ b/pod/perlstyle.pod @@ -6,17 +6,18 @@ perlstyle - Perl style guide Each programmer will, of course, have his or her own preferences in regards to formatting, but there are some general guidelines that will -make your programs easier to read, understand, and maintain. +make your programs easier to read, understand, and maintain. The most important thing is to run your programs under the B<-w> flag at all times. You may turn it off explicitly for particular -portions of code via the C<$^W> variable if you must. You should +portions of code via the C pragma or the C<$^W> variable +if you must. You should also always run under C or know the reason why not. The C and even C pragmas may also prove useful. Regarding aesthetics of code lay out, about the only thing Larry -cares strongly about is that the closing curly brace of +cares strongly about is that the closing curly bracket of a multi-line BLOCK should line up with the keyword that started the construct. Beyond that, he has other preferences that aren't so strong: @@ -154,13 +155,13 @@ the middle. Just "outdent" it a little to make it more visible: =item * Don't be afraid to use loop labels--they're there to enhance -readability as well as to allow multi-level loop breaks. See the +readability as well as to allow multilevel loop breaks. See the previous example. =item * Avoid using grep() (or map()) or `backticks` in a void context, that is, -when you just throw away their return values. Those functions all +when you just throw away their return values. Those functions all have return values, so use them. Otherwise use a foreach() loop or the system() function instead. @@ -178,7 +179,7 @@ determined by the B program when Perl was installed. Choose mnemonic identifiers. If you can't remember what mnemonic means, you've got a problem. -=item * +=item * While short identifiers like $gotit are probably ok, use underscores to separate words. It is generally easier to read $var_names_like_this than @@ -190,19 +191,19 @@ reserves lowercase module names for "pragma" modules like C and C. Other modules should begin with a capital letter and use mixed case, but probably without underscores due to limitations in primitive file systems' representations of module names as files that must fit into a -few sparse bites. +few sparse bytes. =item * -You may find it helpful to use letter case to indicate the scope -or nature of a variable. For example: +You may find it helpful to use letter case to indicate the scope +or nature of a variable. For example: - $ALL_CAPS_HERE constants only (beware clashes with perl vars!) - $Some_Caps_Here package-wide global/static - $no_caps_here function scope my() or local() variables + $ALL_CAPS_HERE constants only (beware clashes with perl vars!) + $Some_Caps_Here package-wide global/static + $no_caps_here function scope my() or local() variables -Function and method names seem to work best as all lowercase. -E.g., $obj-Eas_string(). +Function and method names seem to work best as all lowercase. +E.g., $obj-Eas_string(). You can use a leading underscore to indicate that a variable or function should not be used outside the package that defined it. @@ -227,12 +228,12 @@ Use here documents instead of repeated print() statements. =item * Line up corresponding things vertically, especially if it'd be too long -to fit on one line anyway. +to fit on one line anyway. - $IDX = $ST_MTIME; - $IDX = $ST_ATIME if $opt_u; - $IDX = $ST_CTIME if $opt_c; - $IDX = $ST_SIZE if $opt_s; + $IDX = $ST_MTIME; + $IDX = $ST_ATIME if $opt_u; + $IDX = $ST_CTIME if $opt_c; + $IDX = $ST_SIZE if $opt_s; mkdir $tmpdir, 0700 or die "can't mkdir $tmpdir: $!"; chdir($tmpdir) or die "can't chdir $tmpdir: $!"; @@ -242,7 +243,7 @@ to fit on one line anyway. Always check the return codes of system calls. Good error messages should go to STDERR, include which program caused the problem, what the failed -system call and arguments were, and VERY IMPORTANT) should contain the +system call and arguments were, and (VERY IMPORTANT) should contain the standard system error message for what went wrong. Here's a simple but sufficient example: @@ -250,7 +251,7 @@ sufficient example: =item * -Line up your translations when it makes sense: +Line up your transliterations when it makes sense: tr [abc] [xyz]; @@ -260,7 +261,8 @@ Line up your translations when it makes sense: Think about reusability. Why waste brainpower on a one-shot when you might want to do something like it again? Consider generalizing your code. Consider writing a module or object class. Consider making your -code run cleanly with C and B<-w> in effect. Consider giving away +code run cleanly with C and C (or B<-w>) in effect +Consider giving away your code. Consider changing your whole world view. Consider... oh, never mind.