The main goal of this change is to free the potential Merlin users
from the burden of writing their custom templates when it just
involves combining widgets into different levels of nesting. Writing
custom templates still remains obligatory when some additional
controls/rendering (not provided with built-in widgets) is needed,
e.g. YAQLField.
To ease the pain of laying out the DOM snippets not known in advance I
switched from conventional Bootstrap Grid system to the Flexgrid
package which reimplements Bootstrap Grid over CSS3 Flexbox module. It
provides all the existing grid features w/o the need to cancel
floating effects with div.clearfix and adds pretty vertical/horizontal
aligning options which are very useful in Merlin.
Besides templates refactoring the filters system was also
rewritten. Filter extractPanels() now accepts one required argument,
keyExtractor function which is used to calculate a numeric values for
every field of Barricade object recursively. The fields with the same
numeric values go to the same panel, so we could define the logic of
panel extraction separately for each application built on Merlin. For
the filters following on the pipeline extractPanels() provides .each()
method, which they should use for enumeration over the panel
contents. This way the panel implements the same interface as every
other Barricade container does.
Old extractRows() and extractItems() filters are removed, as well as
the necessity to embed positioning hints into the model. As of now
precise fields ordering is lost, but will be reimplemented with an
extractFields() upgrade (ability to pass a list of field keys is yet
to come, as well as the removal of 'index' hints).
Implements blueprint: composable-templates
Implements blueprint: decouple-ui-hints-and-models
Change-Id: I73f480034730099b33afec88cddf919a7bfc441b
f605ff7b8c