booleanflags:ToBoolean

note

This article is about the booleanflags:ToBoolean Blend function.

booleanflags:ToBoolean

Attempts to convert a string to boolean true() or boolean false() by applying a special "flag-based string-to-boolean conversion" principle. This principle consists of using an internal list that is a mapping between string values and truth values.

You can view this internal list by calling the booleanflags:Show() function. You can add to this list by calling the pc:define-boolean-flags directive.

The "flag-based string-to-boolean conversion" principle contrasts with the XSLT 1.0 rules for string-to-boolean conversion, which state that any non-empty string converts to true() and only the empty string converts to false() .

The flag-based conversion is performed case-insensitively. If yes is associated to boolean true(), then so are Yes and YES.

Syntax

Namespace declaration

You need to declare this namespace only if you call the function directly from the USCSXSL component but outside Blend. In a Blend context (ublendit.exe, uscsxsl.blend()) the namespace is already declared in the Blend transformation, which is in xsl\Util\Batch.1.0.xsl in your USoft installation folder.

xmlns:booleanflags="USoft:BooleanFlags"

Function call

booleanflags:ToBoolean( *string* )

The required string is the string value that you want to convert using "flag-based string-to-boolean conversion".

Example

This example returns the text "Executed verbosely" if the runtime user passes one of the following on the command line:

verbose=true
verbose=yes

but not if he passes one of the following, or nothing at all:

verbose=false
verbose=no

The booleanflags:ToBoolean() function is necessary to get this behaviour. If it were omitted, the text "Executed verbosely" would always appear because the test would be whether or not the verbose variable had a non-empty string as a value. This is always the case because of the pc:assign-string-default line.

<example xmlns:pc="Processing.Command">
  <pc:assign-string-default verbose="no"/>
  <pc:if-then test="booleanflags:ToBoolean($verbose)">
      Executed verbosely
  </pc:if-then>
</example>