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IF

[if type field op* compare*]
named attributes: [if type="type" term="field" op="op" compare="compare"]

[if !type field op* compare*]
named attributes: [if type="!type" term="field" op="op" compare="compare"]

Allows conditional building of HTML based on the setting of various MiniVend session and database values. The general form is:

    [if type term op compare]
    [then]
                                If true, this is printed on the document.
                                The [then] [/then] is optional in most
                                cases. If ! is prepended to the type
                                setting, the sense is reversed and
                                this will be output for a false condition.
    [/then]
    [elsif type term op compare]
                                Optional, tested when if fails
    [/elsif] 
    [else]
                                Optional, printed when all above fail
    [/else]
    [/if]

The [if] tag can also have some variants:

    [if explicit][condition] CODE [/condition]
                Displayed if valid Perl CODE returns a true value.
    [/if]

You can do some Perl-style regular expressions, and combine conditions:

    [if value name =~ /^mike/i]
                                This is the if with Mike.
    [elsif value name =~ /^sally/i]
                                This is an elsif with Sally.
    [/elsif]
    [elsif value name =~ /^barb/i]
    [or value name =~ /^mary/i]
                                This is an elsif with Barb or Mary.
    [elsif value name =~ /^pat/i]
    [and value othername =~ /^mike/i]
                                This is an elsif with Pat and Mike.
    [/elsif]
    [else]
                                This is the else, no name I know.
    [/else]
    [/if]

While the named parameter tag syntax works for [if ...], it is more convenient to use the positional syntax in most cases. The only exception is if you are planning on doing a test on the results of another tag sequence:

    [if value name =~ /[value b_name]/]
        Shipping name matches billing name.
    [/if]

Oops! This will not work. You must do instead

    [if type=value term=name op="=~" compare="/[value b_name]/"]
        Shipping name matches billing name.
    [/if]

or

    [if type=value term=high_water op="<" compare="[shipping]"]
        Shipping cost is too high, charter a truck.
    [/if]

If you wish to do AND and OR operations, you will have to use [if explicit]. This allows complex testing and parsing of values.

There are many test targets available:

config Directive
The MiniVend configuration variables. These are set by the directives in your MiniVend configuration file (or the defaults).

    [if config CreditCardAuto]
    Auto credit card validation is enabled.
    [/if]

data database::field::key
The MiniVend databases. Retrieves a field in the database and returns true or false based on the value.

    [if data products::size::99-102]
    There is size information.
    [else]
    No size information.
    [/else]
    [/if]

    [if data products::size::99-102 =~ /small/i]
    There is a small size available.
    [else]
    No small size available.
    [/else]
    [/if]

discount
Checks to see if a discount is present for an item.

    [if discount 99-102]
    Item is discounted.
    [/if]

explicit
A test for an explicit value. If perl code is placed between a [condition] [/condition] tag pair, it will be used to make the comparison. Arguments can be passed to import data from user space, just as with the [perl] tag.

    [if explicit]
    [condition]
        $country = '[value country]';
        return 1 if $country =~ /u\.?s\.?a?/i;
        return 0;
    [/condition]
    You have indicated a US address.
    [else]
    You have indicated a non-US address. 
    [/else]
    [/if]

This example is a bit contrived, as the same thing could be accomplished with [if value country =~ /u\.?s\.?a?/i], but you will run into many situations where it is useful.

This will work for Variable values:

    [if explicit "__MYVAR__"] .. [/if]

file
Tests for existence of a file. Useful for placing image tags only if the image is present.

    [if file /home/user/www/images/[item-code].gif]
    <IMG SRC="[item-code].gif">
    [/if]

    or 

    [if type=file term="/home/user/www/images/[item-code].gif"]
    <IMG SRC="[item-code].gif">
    [/if]

The file test requires that the SafeUntrap directive contains ftfile (which is the default).

items
The MiniVend shopping carts. If not specified, the cart used is the main cart. Usually used as a litmus test to see if anything is in the cart, for example:

  [if items]You have items in your shopping cart.[/if]
  
  [if items layaway]You have items on layaway.[/if]

ordered
Order status of individual items in the MiniVend shopping carts. If not specified, the cart used is the main cart. The following items refer to a part number of 99-102.

  [if ordered 99-102] ... [/if]
    Checks the status of an item on order, true if item
    99-102 is in the main cart.

  [if ordered 99-102 layaway] ... [/if]
    Checks the status of an item on order, true if item
    99-102 is in the layaway cart.

  [if ordered 99-102 main size] ... [/if]
    Checks the status of an item on order in the main cart,
    true if it has a size attribute.

  [if ordered 99-102 main size =~ /large/i] ... [/if]
    Checks the status of an item on order in the main cart,
    true if it has a size attribute containing 'large'.
    THE CART NAME IS REQUIRED IN THE OLD SYNTAX. The new
    syntax for that one would be:

    [if type=ordered term="99-102" compare="size =~ /large/i"]

    To make sure it is exactly large, you could use:

    [if ordered 99-102 main size eq 'large'] ... [/if]

  [if ordered 99-102 main lines] ... [/if]
      Special case -- counts the lines that the item code is
      present on. (Only useful, of course, when mv_separate_items
      or SeparateItems is defined.)

salestax
The salestax database.

    [if salestax [value state] > 0]
    There is salestax for your state.
    [else]
    No salestax for your state.
    [/else]
    [/if]

Key matching is case-insensitive.

scratch
The MiniVend scratchpad variables, which can be set with the [set name]value[/set] element.

    [if scratch mv_separate_items]
    Ordered items will be placed on a separate line.
    [else]
    Ordered items will be placed on the same line.
    [/else]
    [/if]

session
The MiniVend session variables. Of particular interest are login, frames, secure, and browser.

shipping
The shipping database.

validcc
A special case, takes the form [if validcc no type exp_date]. Evaluates to true if the supplied credit card number, type of card, and expiration date pass a validity test. Does a LUHN-10 calculation to weed out typos or phony card numbers.

value
The MiniVend user variables, typically set in search, control, or order forms. Variables beginning with mv_ are MiniVend special values, and should be tested/used with caution.

The field term is the specifier for that area. For example, [if session frames] would return true if the frames session parameter was set.

As an example, consider buttonbars for frame-based setups. It would be nice to display a different buttonbar (with no frame targets) for sessions that are not using frames:

    [if session frames]
        [buttonbar 1]
    [else]
        [buttonbar 2]
    [/else]
    [/if]

Another example might be the when search matches are displayed. If you use the string [value mv_match_count] titles found, it will display a plural for only one match. Use:

    [if value mv_match_count != 1]
        [value mv_match_count] matches found.
    [else]
        Only one match was found.
    [/else]
    [/if]

The op term is the compare operation to be used. Compare operations are as in Perl:

    ==  numeric equivalence
    eq  string equivalence
    >   numeric greater-than
    gt  string greater-than
    <   numeric less-than
    lt  string less-than
    !=  numeric non-equivalence
    ne  string equivalence

Any simple perl test can be used, including some limited regex matching. More complex tests are best done with [if explicit].

[then] text [/then]
This is optional if you are not nesting if conditions, as the text immediately following the [if ..] tag is used as the conditionally substituted text. If nesting [if ...] tags you should use a [then][/then] on any outside conditions to ensure proper interpolation.

[elsif type field op* compare*]
named attributes: [elsif type="type" term="field" op="op" compare="compare"]

Additional conditions for test, applied if the initial [if ..] test fails.

[else] text [/else]
The optional else-text for an if or if-item-field conditional.

[condition] text [/condition]
Only used with the [if explicit] tag. Allows an arbitrary expression in Perl to be placed inside, with its return value interpreted as the result of the test. If arguments are added to [if explicit args], those will be passed as arguments are in the [perl] construct.

[/if]
Terminates an if conditional.


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