Currently the "workflow" of field validation in Mapper often goes as follows
(not using ajax):
User loads a page containing say fields generated by toForm on the field or
the mapper
User presses save, submitting his data
The data goes into the fields
Validators are called and one fails so instead of saving and redirecting the
same page is loaded
The inputs contain the values in the MappedFields, some of which need to be
modified so the mapper can be saved. Messages are displayed indicating the
problem with whichever field.
There is one serious limitation of this sequence which is that it uses
validators that operate on data in the field and act as a gatekeeper preventing
them from going from the mapper into the database. They do not deal with values
that can't get into the mapper in the first place! So if you enter a date and
it parses incorrectly you don't get to edit it but a blank field and message
telling you what you did wrong but not showing your input for reference.
It's not really the job of a validator. The MappedFields already decide whether
a string input can be parsed in--they just leave no tracks.
This is also relevant when
def f(x: String) = {field.setFromAny(x); field.is.toString==x}
is false.
I'm interested in hearing whatever suggestions and thoughts people have, but
here's my suggestion.
My opinion is that MappedField or one of the common base traits should have a
member to remember the input string.
Or maybe better yet something along these lines:
trait FormField {
type T
def is: T
var inputString: Option[String] = None
def parseIn(s: String) = inputString = Some(s) // subclasses should override
and call super
def formXml(name, String, value: String): NodeSeq
def toForm: NodeSeq = S.fmapFunc((s:List[String])=>parseIn(s))(name =>
formXml(name, inputString.getOrElse(value))
}
(Vague sketch)
In other words, the concept of an html form provider could be moved to its own
trait, which could provide logic for trapping parse errors, and MappedField
could inherit from that trait.
Thoughts?
Thanks.
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