[go-nuts] CSV additional API

On Thursday, July 16, 2015 at 6:41:51 PM UTC-5, John McConnell wrote:

Hello,

I am looking for feedback for an additional api for encoding/csv.

Example:

type CSVStrategy func(string, CSVRow)


type Foo struct {
name string
date Date
number int
}


interface CSVParsable {
func CSVStrategies() map[string]CSVStrategy
}


type CSVRow struct {
header *map[string]int
row []string
}


func (r *CSVRow) At(i int) string {
return r.row[i]
}


func (r *CSVRow) Fetch(name string) string {
return r.row[r.header[name]]
}


func (f *Foo) CSVStrategies() map[string]CSVStrategy {
strategies := map[string]CSVStrategy {
"name": func(field string, r CSVRow) {
f.name = field
},

"date": func(field string, r CSVRow) {
d := r.Fetch("date")
if d == nil {
d = r.Fetch("adjusted_date")
}
f.date = date.Parse(d)
},
"date": func(field string, r CSVRow) {
f.date = int.Parse(field)
},
}
return strategies
}

--

Hello Paul,

I thought about this design when I was creating code to convert a CSV
file into a list of objects. I noticed I was doing a lot of duplication.
Putting it into a separate package is fine. I think there is at least one
strength of having it in the core library:

In order to convert a row in a CSV file to an struct, a developer will
only need to define one method. Also, this method will only have one
responsibility (csv decoding). I guess I should have added to this to code.

Parse(os []CSVParsable, csv [][]string) {
i, row := range csv {
if i == 0 {
header := // convert to header
continue
}
csvr := CSVRow{header, row}
o := os[i - 1] // minus one because we don't include the header

strategies := o.ParseStrategies()
for field, parseField := range strategies {
o.parseField(field, csvr)
}
}
}


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