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Breaking changes

Boolean constants

In this release, boolean constants true and false have been changed so that they resolve to values of boolean type (rather than string). This will affect any uses of the is strictly operator on such values, i.e. previously the following were true:

true is strictly a string false is strictly a string

Now, they are both false, and the following are true:

true is strictly a boolean false is strictly a boolean

Boolean constants passed as elements of arrays to LCB handlers will not require conversion to boolean values in LCB - in fact any attempt to do so assuming they are strings will cause an error. Any array elements which are intended to be booleans in LCB should be checked for their type before conversion. For example, any of the following could be done by an LCB library user:

put true into tArray["enabled"]
put "true" into tArray["enabled"]
put (tVar is not "enabled") into tArray["enabled"]

An LCB handler to which tArray is passed should do the following:

variable tEnabled as Boolean
if tArray["enabled"] is a boolean then
    put tAction["enabled"] into tEnabled
else
    put tAction["enabled"] parsed as boolean into tEnabled
end if

Infinity constant

The constant infinity has been added to the language in this release. As a result, the unquoted literal infinity is now reserved. Any existing uses of it should be quoted, as otherwise it will resolve to the floating point value representing infinity, rather than the string "infinity".

Implicit object

A number of LCB commands use an implicit object to provide context for their execution. Some of these commands also allow specifying an explicit object. These commands are:

  • execute script
  • send
  • post
  • image from file
  • resolve file - new in this version

In previous releases execute script and image from file would use this card of the defaultStack as the implicit object even if called from a widget. The send and post commands, however, used this card of the defaultStack when in a library module handler and the host widget when in a widget module handler. This release changes execute script and image from file to also use the host widget as the implicit object. This means, for example, that image from file will resolve a relative file path relative to the stackFile the host widget is on rather than the stackFile of the defaultStack.