* Introduce new widget helper function to evaluate variables.Functions are evaluated as parameterised filter strings, macros as text with textual substitution of parameters and variables, and procedures and widgets as plain text
* Refactor the function operator and unknown operator to use the new helper
* Use the new helper to evaluate variables within filter strings, thus fixing a bug whereby functions called in such a way were being returned as plain text instead of being evaluated
* Refactor the transclude widget to use the new helper
* Update tests
The basic idea is that if we don't find a variable `foo` then we fallback to retrieving the value from the tiddler `$:/global/foo`, if it exists.
This allows us to replace the usual importvariables-based mechanism for global definitions, avoiding cluttering up the variable namespace with every macro.
In order to permit subprocedures to be overridden, we also introduce a mechanism for conditional definitions: preceding the word definition|procedure|function|widget with a + causes the definition only to occur if the specified variable doesn't already exist. In the next commit we'll apply this mechanism to the tabs macro
There are two big changes here:
Replace the previous "ts-wrapper" mechanism, which we had been using to redefine custom widgets inside their definitions to prevent recursive calls. Now we've got the genesis widget we can instead control recursion through a new "$remappable" attribute that allows the custom widget mechanism to be skipped.
We also extend the slot widget to allow a depth to be specified; it then reaches up by the indicated number of transclusion widgets to find the one from which it should retrieve the slot value.
* Support direct style attributes on the element widget
* Fix tests
Not all parse tree nodes have an "orderedAttributes" member (eg. the error message generated at 5613bcc884/core/modules/widgets/transclude.js (L73-L75))
* Ensure ordering isn't insertion dependent if orderedAttributes is missing
* Add docs
* Support macro params in filter run prefixes and support substitution for variables set by filter run prefixes
* feat: add support macro parameters and variable substitution for all filter run prefixes
* fix: rename options argument to opts for disambiguation
* feat: add support for macro params to cascade filterrun prefix
* $let widget added and tested
* Documentation for $let, doc improvements for $vars
* let properly avoids refreshing when possible
* $let Changes as recommended by others
* Removed superfluous super method call
Also improved $let test
