[FE-discuss] multiple or combined messages from compound validator

[Ed Hillis]

I would like to have a compound validator give the error message for each of
it elements. For example, if my field could not be empty and it required an
Int, the output would be something like:

field: 'Please enter something, Must be an integer'

instead of just showing one or the other. Is there a built-in way to do
this? I am completely new here, and may be overlooking any obvious solution.
Thanks -Ed

[Mike Orr]

Post by Ed Hillis
I would like to have a compound validator give the error message for each of
it elements. For example, if my field could not be empty and it required an
field: 'Please enter something, Must be an integer'
instead of just showing one or the other. Is there a built-in way to do
this? I am completely new here, and may be overlooking any obvious solution.
Thanks -Ed

I'm not quite sure what you mean. I use the following for select lists
whose value is an int:

===
class SelectInt(v.FancyValidator):
"""A combination of the Int and OneOf validators with a custom message"""
__unpackargs__ = ("list",)
not_empty = True

def _to_python(self, value, state):
try:
return int(value)
except ValueError:
self._invalid(value, state)

_from_python = _to_python

def validate_python(self, value, state):
if value not in self.list:
self._invalid(value, state)

def _invalid(self, value, state):
message = "please choose an item from the list"
raise v.Invalid(message, value, state)
===

I also use a custom error message for regular int validators:

===
class Int(v.Int):
messages = {
"integer": _("Please enter a numeric value"),
}
===

If by "compound validator" you mean that it validates several widgets
together, you can do that with a chained validator, which takes a dict
of values and error messages rather than scalar strings.

For nested validators (e.g., a latitude-longitude widget with multiple
fields for degrees, minutes, and seconds), you'd create a Schema
validator for it, and make sure that 'pre_validators =
[NestedVariables()]'. Then the Python value of the subwidget would
appear as a nested dict in Python, and your form would contain widgets
like this:

.<input name="lat_lon.lat_deg" type="text" />