if

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## if

CALL INFORMATION
  Parameters: type term op compare

  THIS TAG HAS SPECIAL POSITIONAL PARAMETER HANDLING.

  Pass attribute hash as last to subroutine: no

  Must pass named parameter interpolate=1 to cause interpolation.

  This is a container tag, i.e. [if] FOO [/if]. Nesting: NO

  Invalidates cache: YES

  Called Routine:

  Called Routine for positonal:

  ASP/perl tag calls:

          $Tag->if(
              {
               type => VALUE,
               term => VALUE,
               op => VALUE,
               compare => VALUE,
              },
              BODY
          )

       OR

          $Tag->if($type, $term, $op, $compare, $BODY);

  Attribute aliases

                  base ==> type
                  comp ==> compare
                  condition ==> compare
                  operator ==> op

DESCRIPTION
  Named call example: [if type=``type'' term=``field'' op=``op'' compare=``compare'']

  Positional call example: [if type field op compare]

  negated: [if type=``!type'' term=``field'' op=``op'' compare=``compare'']

  Positional call example: [if !type field op 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 type=explicit compare=`$perl_code`]
              Displayed if valid Perl CODE returns a true value.
          [/if]

  You can do some Perl-style regular expressions:

          [if value name =~ /^mike/]
                                      This is the if with Mike.
          [elsif value name =~ /^sally/]
                                      This is an elsif with Sally.
          [/elsif]
          [elsif value name =~ /^pat/]
                                      This is an elsif with Pat.
          [/elsif]
          [else]
                                      This is the else, no name I know.
          [/else]
          [/if]

  While named parameter tag syntax works for `[if ...]`, it is more convenient to use positional calls 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 base=value field=name op="=~" compare="/[value b_name]/"]
              Shipping name matches billing name.
          [/if]

  or better yet

          [if type=explicit compare=`
                              $Value->{name} =~ /$Value->{b_name}/
                              `]
              Shipping name matches billing name.
          [/if]

  MiniVend also supports a limited [and ...] and [or ...] capability:

          [if value name =~ /Mike/]
          [or value name =~ /Jean/]
          Your name is Mike or Jean.
          [/if]

          [if value name =~ /Mike/]
          [and value state =~ /OH/]
          Your name is Mike and you live in Ohio.
          [/if]

  If you wish to do very complex AND and OR operations, you will have to use `[if explicit]` or better yet embedded Perl/ASP. 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 type=explicit compare="__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]

  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] Item 99-102 is in your cart. [/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'.

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

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

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 i<login>, i<frames>, i<secure>, and i<browser>.

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. Uses the standard `CreditCardAuto` variables for targets if nothing else is passed.

value
  the minivend user variables, typically set in search, control, or order forms. variables beginning with c<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 logged_in] would return true if the `logged_in` 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 scratch frames]
            __BUTTONBAR_FRAMES__
        [else]
            __BUTTONBAR__
        [/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_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.

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