New in Tcl? Coming from another language? Read on.
This could be fun. I learned almost all of my programming with PHP, and a little bit of Perl. This sheet [L1 ] helped me an awful lot when I tried to learn Perl, so a Tcl cheat sheet may be awfully useful to someone else. Feel free to add other languages.
PHP: file.php3
PERL: file.cgi
TCL: file.tcl
PHP: scripts in <?php..?>
PERL: whole file is script
TCL: whole file is script
PHP: can include raw HTML
PERL: must print all output
TCL: must print all output
PHP: no requirements for first line
PERL: first line is #!/local/bin/perl (but is that a requirement?)
TCL: first line can be #!/local/bin/tclsh (but that is no requirement)
protections
PHP: not executable file
PERL: executable file
TCL: What the heck? You can make almost any file executable in nix platforms!
PHP: chmod 644 file.php3
PERL: chmod 755 file.cgi
TCL: er... I don't know
printing
PHP: echo "stuff\n";
PERL: print "stuff\n";
TCL: puts stuff OR puts "some stuff" OR puts {some stuff}
variables
PHP: All variables $var
PERL: $var is a scalar variable.
TCL: var or $var - more detailed explanation needed
PHP: $var always means one thing
PERL: $var, @var, %var, var are different things!
TCL: $var always means one thing
arrays
PHP: $var = array(1,2,3);
PERL: @var = (1,2,3);
TCL: well, there are lists...
set var "1 2 3" '''OR''' set var [[ list 1 2 3 ]]
and arrays...
array set var "key1 value1 key2 value2 key3 value3"
PHP: $var[1] is second element of $var
PERL: $var[1] is second element of @var
TCL: [ lindex $var 1 ] is second element of $var
PHP: count($var) is length
PERL: scalar(@var) is length
TCL: [ llength $var ] is length
PHP: for ($i=0; $i<count($var); $i++) echo $var[$i];
PERL: foreach $thing (@var) { print $thing; }
TCL: for { set i 0 } {$i < [ llength $var ] } { incr i } { puts [ lindex $var $i ] }
PHP: join(":",array(1,2,3))
PERL: join(":",(1,2,3))
TCL: join [ list 1 2 3 ] : (yeah, yeah, you can wrap the colon in quotes if you're queasy)
objects
PHP: associative arrays are arrays
PERL: associative arrays are their own type
TCL: Er... what is a "type"? ;-)
PHP: $var = array(1=>"ho","hi"=>4);
PERL: %var = (1=>"ho","hi"=>4);
TCL: array set var "1 ho hi 4"
PHP: $var['ho'] is element indexed by 'ho'
PERL: $var{'ho'} is element of %var
TCL: $var['ho'] is element indexed by 'ho' confusing???
PHP: while (list($k,$v) = each $var)) {...}
PERL: while (($k,$v) = each %var) {...}
TCL: er... foreach { key value } [ array get var ] {...}
to be continued...