Adds a new function to the template interface, and implements it in the
context class. The function returns the ordinal index for a specified key,
with the same structure that the key for alter_block_array.
Reuses same code. Remove unneeded references, do nothing for int keys.
Check out of bounds or wrong blockname errors. Added tests.
Remove default parameter value.
PHPBB3-14944
Adds a new function to the template interface, and implements it in the
context class. The function returns the ordinal index for a specified key,
with the same structure that the key for alter_block_array.
Reuses same code.
PHPBB3-14944
Add one more wrapper template method for the function assign_block_vars() which
takes a 2-dimensional array as a parameter
and calls assign_block_vars() in a loop to assign the whole block loop at once.
This can make the core a little bit more expendable from the point of
developing extensions as it allows to pass the data to events before
it's being assigned to template.
PHPBB3-12224
