macro.catchAbort: Difference between revisions

Revision as of 16:00, 17 March 2019

Introduced in version 1.5.0. The variable macro.catchAbort can be used to override the behavior of the default abort() function to continue execution instead of halting.

Whenever you set macro.catchAbort to 1, any use of abort() in a subsequently called macro will not abort, but will trigger a return from the macro instead.

The variable macro.catchAbort must be in the variable scope where the abort should be caught. It is not a general flag to turn off abort behavior, just temporarily in the macro or variable scope where it's set.

Usage

Set this variable to 0 (default abort behavior) or 1 (catch aborts).

[h: macro.catchAbort = 0]
[h: macro.catchAbort = 1]

Examples

When a macro is called by another macro, the called macro may use abort() to cancel execution. Usually all macro execution would stop, so the calling macro would not continue. We can now override that default behavior by catching the abort.

Default behaviour

The macro below will not have any output because the default behavior is that any call to abort() will stop the overall macro execution. Whatever code is defined after the call to abort() is not executed.

Default abort Macro
[h: resultText = "defaultValue"] [h: resultText = abort(0)] [r: resultText]

Catching the abort

The macro below will output defaultValue as the macro.catchAbort set to 1 prevents the call to abort() from actually terminating execution. The example shows how to set a default value for any return value of a function/macro that has an abort() call in it. The macro then re-enables the normal function of abort() again by setting macro.catchAbort to 0. As each macro has its own variable scope, this only affects calls to abort() within the current macro or calls to other macros from the current macro. The exception is if the called macro shares the scope with the calling macro, in which case the abort is ignored.

Catching abort
[h: macro.catchAbort = 1] [h: resultText = "defaultValue"] [h: resultText = abort(0)] [r: resultText] [h: macro.catchAbort = 0]

Catching the abort with nested macro calls

Same as in the above example, the calling macro below will output defaultValue because we activate catching aborts (in anything that this macro will call afterwards) with macro.catchAbort set to 1 .

Called macro using an abort as function doSomething()

Calling macro catching an abort

[h: "this macro will do something and then abort"]
[h: "... doing something"]
[h: abort(0)]

[h: macro.catchAbort= 1]
[h: resultText = "defaultValue"]
[h: resultText = doSomething()]
[r: resultText]
[h: macro.catchAbort= 0]

Version changes

1.5.0 - introduced macro.abortCatch

@@ Line 35: / Line 35: @@
 ===Catching the abort===
-The macro below will output {{code|defaultValue}} as the {{code|macro.catchAbort}} set to {{code|1}} prevents the call to {{func|abort}} from actually terminating execution. The example shows how to set a default value for any return value of a function/macro that has an {{func|abort}} call in it. The macro then re-enables the normal function of {{func|abort}} again by setting {{code|macro.catchAbort}} to {{code|0}}. As each macro has its own variable scope, this only affects calls to {{func|abort}} within the current macro or calls to other macros from the current macro.
+The macro below will output {{code|defaultValue}} as the {{code|macro.catchAbort}} set to {{code|1}} prevents the call to {{func|abort}} from actually terminating execution. The example shows how to set a default value for any return value of a function/macro that has an {{func|abort}} call in it. The macro then re-enables the normal function of {{func|abort}} again by setting {{code|macro.catchAbort}} to {{code|0}}. As each macro has its own variable scope, this only affects calls to {{func|abort}} within the current macro or calls to other macros from the current macro. The exception is if the called macro shares the scope with the calling macro, in which case the abort is ignored.
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