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try

If a runtime error is detected in the [try]...[/try] block, then Interchange will execute the correspondingly-labelled [catch]...[/catch] block.

Summary

  • [try label] Interchange tag code [/try]

Parameter Description Default
label The label shared by the paired [try] and [catch] blocks default
clean Suppress [try] block output if an error is detected. None
status Returns 0 (failed) or 1 (success) instead of the usual block output. None
hide Suppresses output from the code block. None
interpolate

Parse Interchange tags, included in the body text, before this container tag executes.

No

Examples

The [try] tag will run a block of Interchange tags and trap any errors found. 

[try my_label]
    Body text to parse (and return if no error)
[/try]

The [catch] tag can then handle any errors that were trapped by the [try] block. 

[catch label=my_label other_named_attributes]
    [/Pattern matching error message 1/]
        Return this if error 1 occurs
    [/Pattern matching error message 1/]

    [/Pattern matching error message 2/]
        Return this if error 2 occurs, etc.
    [/Pattern matching error message 2/]

    Default body text to process if try block caused an error

    [else]
        Optional body text to process if there was no error
    [/else]
[/catch]

Description

Allows you to trap errors.  Interchange processes the body text of the [try]...[/try] block and returns it normally, if it does not generate an error.  If an error is detected, interchange will executes the corresponding [catch]...[/catch] block.  The [catch] block executes where it is on the page (i.e. it does not replace the output of the [try] block).

Note

Note

The [catch] block must occur after the [try] block, on the same page.

The try tag will also place a result in the $Session object.  For example, the following returns the "Illegal division by zero" error message:

[set divisor]0[/set]
[try label=div]
    [perl] 1 / $Scratch->{divisor} [/perl]
[/try]
[catch div]
    [/Illegal division by zero/]
        Division by zero
    [/Illegal division by zero/]

    [/eval "string" trapped by operation mask/]
        Perl Safe error
    [/eval "string" trapped by operation mask/]

    Other division error.
[/catch]

The $Session->{try}->{divide} object will be set to an empty string if there was no error or, if there was an error, it will contain the error message.

The [perl], [calc] and [calcn] tags also set $Session->{try}->{active_label} upon error.

Parameters

label

This is the label specifying the corresponding [catch] block.  Defaults to "default".

clean

Setting clean=1 will cause the [try] block to suppress its output only if an error is detected.  Otherwise, if clean is not set true, the [try] block will return whatever partial output it has completed before the error.  If an error is detected then the [catch] block will be executed as usual.

status

Suppresses [try] block output, and instead returns either 1 if no error, or 0 if an error occurred.  If an error is detected then the [catch] block will be executed as usual.

hide

Suppresses [try] block output (regardless of success or failure).  If an error is detected then the [catch] block will be executed as usual.

Category:  Interchange tags
Last modified by: Kevin Walsh
Modification date: Wednesday 13 February 2008 at 4:59 AM (CST)
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