def links_to_jslinks(model, widget):
from ..widgets import Widget
src_links = [Watcher(*l[:-4]) for l in widget._links]
if any(w not in widget._callbacks and w not in src_links
for w in get_watchers(widget)):
return
links = []
for link in widget._links:
target = link.target
tgt_watchers = [
w for w in get_watchers(target) if w not in target._callbacks
]
if link.transformed or (tgt_watchers
and not isinstance(target, Widget)):
return
mappings = []
for pname, tgt_spec in link.links.items():
if Watcher(*link[:-4]) in widget._param_watchers[pname]['value']:
mappings.append((pname, tgt_spec))
if mappings:
links.append((link, mappings))
jslinks = []
for link, mapping in links:
for src_spec, tgt_spec in mapping:
jslink = link_to_jslink(model, widget, src_spec, link.target,
tgt_spec)
if jslink is None:
return
widget.param.trigger(src_spec)
jslinks.append(jslink)
return jslinks
def param_to_jslink(model, widget):
"""
Converts Param pane widget links into JS links if possible.
"""
from ..reactive import Reactive
from ..widgets import Widget, LiteralInput
param_pane = widget._param_pane
pobj = param_pane.object
pname = [k for k, v in param_pane._widgets.items() if v is widget]
watchers = [
w for w in get_watchers(widget)
if w not in widget._callbacks and w not in param_pane._callbacks
]
if isinstance(pobj, Reactive):
tgt_links = [Watcher(*l[:-4]) for l in pobj._links]
tgt_watchers = [
w for w in get_watchers(pobj) if w not in pobj._callbacks
and w not in tgt_links and w not in param_pane._callbacks
]
else:
tgt_watchers = []
for widget in param_pane._widgets.values():
if isinstance(widget, LiteralInput):
widget.serializer = 'json'
if (not pname or not isinstance(pobj, Reactive) or watchers
or pname[0] not in pobj._linkable_params
or (not isinstance(pobj, Widget) and tgt_watchers)):
return
return link_to_jslink(model, widget, 'value', pobj, pname[0])