Method for applying "represent" attributes to rows

[Anthony]

How about adding the method below to the DAL Rows class? It allows transformation of values within a Row based on the "represent" attributes of the fields:

rows = db(query).select()
repr_row = rows.repr(0)

If you don't specify an index, you get a generator to iterate over all the rows:

for row in rows.repr():
    print row.myfield

Can also be applied to slices:

for row in rows[0:10].repr():
    print row.myfield

If you only want to transform selected fields via their "represent" attribute, you can list them in the "fields" argument:

repr_row = row.repr(0, fields=[db.mytable.myfield])

Note, it returns a transformed copy of the original Row, so there's no update_record (which you wouldn't want anyway) or delete_record.

Thoughts? Here's the code:

    def repr(self, i=None, fields=None):
        """
        Takes an index and returns a copy of the indexed row with values
        transformed via the "represent" attributes of the associated fields.
       
        If no index is specified, a generator is returned for iteration
        over all the rows.
       
        fields -- a list of fields to transform (if None, all fields with
                  "represent" attributes will be transformed).
        """


        if i is None:
            return (self.repr(i, fields=fields) for i in range(len(self)))
        import sqlhtml
        row = copy.copy(self.records[i])
        keys = row.keys()
        tables = [f.tablename for f in fields] if fields \
                 else [k for k in keys if k != '_extra']
        for table in tables:
            repr_fields = [f.name for f in fields] if fields \
                          else [k for k in row[table].keys()
                                if (hasattr(self.db[table], k) and
                                isinstance(self.db[table][k], Field)
                                and self.db[table][k].represent)]
            for field in repr_fields:
                row[table][field] = sqlhtml.represent(self.db[table][field],
                    row[table][field], row[table])
        if self.compact and len(keys) == 1 and keys[0] != '_extra':
            return row[keys[0]]
        return row

Anthony

[Anthony]

Oops, small fix in code below:

    def repr(self, i=None, fields=None):
        """
        Takes an index and returns a copy of the indexed row with values
        transformed via the "represent" attributes of the associated fields.
       
        If no index is specified, a generator is returned for iteration
        over all the rows.
       
        fields -- a list of fields to transform (if None, all fields with
                  "represent" attributes will be transformed).
        """


        if i is None:
            return (self.repr(i, fields=fields) for i in range(len(self)))
        import sqlhtml
        row = copy.copy(self.records[i])
        keys = row.keys()
        tables = [f.tablename for f in fields] if fields \
                 else [k for k in keys if k != '_extra']
        for table in tables:

            repr_fields = [f.name for f in fields if f.tablename == table] if fields \

                          else [k for k in row[table].keys()
                                if (hasattr(self.db[table], k) and
                                isinstance(self.db[table][k], Field)
                                and self.db[table][k].represent)]
            for field in repr_fields:
                row[table][field] = sqlhtml.represent(self.db[table][field],
                    row[table][field], row[table])
        if self.compact and len(keys) == 1 and keys[0] != '_extra':
            return row[keys[0]]
        return row

Anthony

[Massimo DiPierro]

I like it! In trunk. :-)

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[Alan Etkin]

El viernes, 21 de junio de 2013 03:52:00 UTC-3, Massimo Di Pierro escribió:

I like it! In trunk. :-)

Is this ok (or should they return the same)?

>>> repr(rows)
'<Rows (3)>'
>>> rows.repr()
<generator object <genexpr> at 0xa86ea04>

EDIT: Perhaps it would be less confusing if the new method was named Rows.represent

[Massimo DiPierro]

This is ok because

repr(rows) is the same as rows.__repr__() not of rows.repr() Yet the latter should be renamed to avoid confusion. Suggestions for a better name? "represent" perhaps?

On Jun 21, 2013, at 6:04 AM, Alan Etkin wrote:

El viernes, 21 de junio de 2013 03:52:00 UTC-3, Massimo Di Pierro escribió:

I like it! In trunk. :-)

Is this ok (or should they return the same)?

>>> repr(rows)
'<Rows (3)>'
>>> rows.repr()
<generator object <genexpr> at 0xa86ea04>

[Anthony]

I thought about this and opted for .repr() just to keep it shorter. I was also concerned that rows.represent() might be confused with db.mytable.myfield.represent() (the former uses the latter, but they have different signatures). Perhaps there is a third alternative, though I haven't thought of a good one yet. Anyway, I wouldn't object to rows.represent() if everyone prefers that.

Anthony

[Massimo DiPierro]

So.... this is in but I think we need a better name. Suggestions?

On Jun 20, 2013, at 10:24 PM, Anthony wrote:

[Niphlod]

render ?

[Anthony]

OK, here are some options for the name:

rows.repr()
rows.represent()
rows.repr_fields()
rows.field_repr()
rows.render()
rows.display()

Another option might be to use the __call__ method and generalize it to return a copy of a row, optionally (and by default) transformed via the "represent" attributes of its fields. So, you would do:

row_copy = rows(1)  # uses the "represent" attributes by default
row_copy = rows(1, represent_fields=False)  # just a plain copy -- no represent used
row_copy = rows(1, represent_fields=[db.mytable.myfield1, db.mytable.myfield2])  # represent specific fields
for row_copy in rows():  # iterate through all the rows

Here's the code for the __call__ method (note, this also fixes a couple problems with the original method, such as doing a deepcopy instead of a copy):

    def __call__(self, i=None, represent_fields=True):
        """
        Takes an index and returns a copy of the indexed row, by default
        transforming each value via the "represent" attribute of the

        associated fields.
        

        If no index is specified, a generator is returned for iteration

        over all the rows.

        :represent_fields (defaults to True): indicates field values are to be
            transformed via their "represent" attributes. Can also be a list of
            specific fields to transform.

        """

        if i is None:
            return (self.__call__(i, represent_fields=represent_fields)

                    for i in range(len(self)))
        import

sqlhtml
        row = copy.deepcopy(self.records[i])
        keys = row.keys()
        if represent_fields:
            field_list = isinstance(represent_fields, (list, tuple))
            tables = [f.tablename for f in represent_fields] if field_list \

                     else [k for k in keys if k != '_extra']
            for table in tables:

                if field_list:
                    fields = [f.name for f in represent_fields
                              if f in self.db[table].fields]
                else:
                    fields = [k for k in row[table].keys()

                              if (hasattr(self.db[table], k)
                              and isinstance(self.db[table][k], Field)
                              and self.db[table][k].represent)]

                for field in fields:

                    row[table][field] = sqlhtml.represent(self.db[table][field],
                        row[table][field], row[table])
        if self.compact and len(keys) == 1 and keys[0] != '_extra':
            return row[keys[0]]
        return row

Anthony

[Massimo DiPierro]

I like

rows.render()

On Jul 2, 2013, at 10:56 PM, Anthony wrote:

OK, here are some options for the name:

rows.repr()
rows.represent()
rows.repr_fields()
rows.field_repr()
rows.render()
rows.display()

Another option might be to use the __call__ method and generalize it to return a copy of a row, optionally (and by default) transformed via the "represent" attributes of its fields. So, you would do:

row_copy = rows(1)  # uses the "represent" attributes by default
row_copy = rows(1, represent_fields=False)  # just a plain copy -- no represent used
row_copy = rows(1, represent_fields=[db.mytable.myfield1, db.mytable.myfield2])  # represent specific fields
for row_copy in rows():  # iterate through all the rows

Here's the code for the __call__ method (note, this also fixes a couple problems with the original method, such as doing a deepcopy instead of a copy):

    def __call__(self, i=None, represent_fields=True):
        """

        Takes an index and returns a copy of the indexed row, by default

        transforming each value via the "represent" attribute of the

        associated fields.
       
        If no index is specified, a generator is returned for iteration
        over all the rows.

        :represent_fields (defaults to True): indicates field values are to be
            transformed via their "

represent" attributes. Can also be a list of
            specific fields to transform.

        """

        if i is None:
            return (self.__call__(i, represent_fields=represent_fields)

                    for i in range(len(self)))
        import

sqlhtml
        row = copy.deepcopy(self.records[i])
        keys = row.keys()

        if represent_fields:
            field_list = isinstance(represent_fields, (list, tuple))

            tables = [f.tablename for f in represent_fields] if field_list \

                     else [k for k in keys if k != '_extra']
            for table in tables:

                if field_list:
                    fields = [f.name for f in represent_fields
                              if f in self.db[table].fields]
                else:

                    fields = [k for k in row[table].keys()

                              if (hasattr(self.db[table], k)
                              and isinstance(self.db[table][k], Field)
                              and self.db[table][k].represent)]

                for field in fields:

                    row[table][field] = sqlhtml.represent(self.db[table][field],
                        row[table][field], row[table])
        if self.compact and len(keys) == 1 and keys[0] != '_extra':
            return row[keys[0]]
        return row

Anthony

On Wednesday, June 26, 2013 4:45:55 AM UTC-4, Niphlod wrote:

[Anthony]

Don't like the __call__ idea?

 

.render() seems OK, but I thought it might imply that the entire row would be rendered to an HTML structure. I was thinking maybe something like .display() might be less confusing.

 

Anthony

[Alan Etkin]

Don't like the __call__ idea?

 

.render() seems OK, but I thought it might imply that the entire row would be rendered to an HTML structure. I was thinking maybe something like .display() might be less confusing.

I'd use Rows.represent and would clarify the difference everywhere needed (book, docstrings). IMO It's not expect that a Rows object supports assignment as with the Field class nor override the Field class represent settings.

[Anthony]

I'd use Rows.represent and would clarify the difference everywhere needed (book, docstrings). IMO It's not expect that a Rows object supports assignment as with the Field class nor override the Field class represent settings.

What do you mean by "assignment" and overriding the represent settings?

Anthony 

[Alan Etkin]

What do you mean by "assignment" and overriding the represent settings?

I meant that I don't expect a Rows class object to allow me to do:

rows.represent = lambda name, row: ...

and that shouldn't be necessary to set that attribute to override the field representation set with

db.mytable.myfield.represent = lambda ...

for the specific rows render, since it would be possible to set db.mytable.myfield.represent temporarily instead.

But if the Rows class is going to support something like

rows.represent = {"myfield": lambda value, row: ..., "otherfield": ...}

then it's not possible to change the Row.repr method name to Row.represent

[Anthony]

I see. Yeah, I think my favorites so far are rows.represent() and rows.display().

Anthony

[Massimo DiPierro]

I just committed rows.render() although this is not be the final word about it.

[Richard Vézina]

Is the utility of this to allow access or create a representation of a record in case of construction of a custom table (TABLE(...))??

I need badly a way to set the representation of the record in a custom table, I may just don't know how to do it though.

Thanks

Richard