*   PHP is running on redwood --- put your .php file in your public_html
    directory on redwood, and then, for user abc23 with php file
    myfile.php, the URL would be:

    http://redwood.humboldt.edu/~abc23/myfile.php

*   more PHP language basics:

*   (oops --- PHP statements DO terminate with a semicolon,
    but the closing tag ?> sticks one in...!)

*   addendum to PHP variable basics:

    *   after the $, needs to start with letter or underscore

        ... followed by any number of letters, digits, or underscores

    *   PHP IS case sensitive!

*   PHP types...

    *   the type of a variable is NOT set by the programmer ---

        instead, it is decided at runtime BY PHP, depending on
        the CONTEXT in which that variable is used;

    *   supports 8 primitive types:
        *   4 scalar types...
            *   boolean (2 literals: TRUE FALSE)
            *   integer
            *   float
            *   string

        *   2 compound types:
            *   array
            *   object

        *   2 special types:
            *   resource
            *   NULL

    *   if you'd like a human-friendly printout of the type of a
        variable,  gettype function provides that...

        print gettype($a_variable);

    *   BUT for seeing if something is of a particular type,
        better to use the is_<type> functions...

        is_int($var)

        is_string($var)

    *   see: type_play.php        

*   operators
    *   . for string concatenation (like Perl, unlike Java)

    *   arithmetic operators: pretty much like you'd guess!

        + - * /

    *   operator precedence: also mostly what you'd expect ---
        see 
http://www.php.net/manual/en/language.operators.php#language.operators.precedence

    *   = is assignment

    *   ++ -- are there, too

    *   comparisons evaluate to TRUE or FALSE (starting in PHP 4)
        > >= < <=

        == does compare for equality
        != does compare for inequality

        BUT:   === equal to and same type
               !== not equal to OR not same type

    *   += *= -= /=

*   how about logical/boolean operators?

    *   and or
        &&  ||

	...both! BUT && and || have higher operator precedence!

        and ! for not...

*   what about the branching structure?

    *   PHP has an if that's VERY similar to C++/Java

        if (expr)
        {
             sttmt;
             sttmt;
        }

    *   yes, you can have an else:

        if (expr)
        {
             sttmt;
             sttmt;
        }
        else
        {
             sttmt;
             sttmt;
        }

    *   SLIGHT twist: there is also an optional elseif

        if (expr)
        {
             sttmt;
             sttmt;
        }
        elseif (expr)
        {
             sttmt;
             sttmt;
        }
        else
        {
             sttmt;
             sttmt;
        }

    *   see if_and_equality.php

*   what about repetition?

    *   there are while and for loops that should look very familiar!

        (and other loops, too)

    *   while

        while (expr)
        {
            sttmt;
            sttmt;
        }

    *   for

        for (<init>; <cond>; <update>)
        {
            sttmt;
            sttmt;
        }

        for ($i = 0; $i < $something; $i++)
        {
            sttmt;
            sttmt;
        }
        
    *   see loops1.php

*   and, how about the function/procedure structure?

    *   many functions ARE built-in --- see: http://www.php.net/quickref.php

    *   but, you can write your own, also...

        function <function_name> ( <parameters_sep'd_by_commas> )
        {
            // function code

            return <expr>;  // if desired
            return; // if desired
        }

   *   (return DOES have you leave the function....)

   *   see try_funct1.php, hello_funct.php

*   and note that you can break "out" of PHP to insert HTML,
    pretty much anywhere --- see if_and_more.php

*   what if code is in another file?

    include() statement includes and evaluates the specified file

    *   see vars.php, include1.php

*   so, let's say a few words about arrays...

    *   really an ordered map, in PHP...
 
    *   (maps values to keys...)

    *   one way to set up an array in PHP:

        array() language construct

        $shopping = array("fruit" => "apple", 13 => 9, 
                          "cereal" => "Grape Nuts");

    *   then, to grab the element corresponding to a key....

        print $shopping["fruit"]
        print $shopping[13]
        print $shopping["cereal"]

    *   what if you don't GIVE a key for a value?

        *   then it'll find the maximum integer index included,
            and a key that's that max + 1 will be assigned to such
            a value.

        *   what if there ARE no integer indices at the time?!
            ... then it starts at index 0

        *   foreach loop to walk through array:

	    foreach ($arr as $value)

            *   $arr is the array to iterate through

            *   $value is SET to each value in the array $arr in turn

            foreach ($arr as $key => $value)

            *   $arr is the array to iterate through

            *   $key is SET to each key in the array in turn,
                and $value is set to that $key's value in turn

    *   array1.php plays with this, now, too!
        
    *   and to assign a new key-value pair within the array?

        $my_arr[<new_key>] = <value>

        (note that assigning to a key REPLACES its former value, if there)

    *   this is in array1.php, too

    *   in PHP, keys are limited to strings and integers;

        ...but VALUES can be ANY PHP type