Functional programming in go. The main data type, Stream, is similar to a python iterator or generator. The methods found in here are similar to the methods found in the python itertools module. This is version 3 of gofunctional.

This API is now stable and will not change in incompatible ways. New functions added may be marked as provisional, draft API.

import "github.com/keep94/gofunctional3/functional"
import "github.com/keep94/gofunctional3/consume"

Click here to see the release notes and what changed since gofunctional2.

Suppose there are names and phone numbers of people stored in a sqlite database. The table has a name and phone_number column.

The person class would look like:

type Person struct {
  Name string
  Phone string
}

func (p *Person) Ptrs() {
  return []interface{}{&p.Name, &p.Phone}
}

To get the 4th page of 25 people do:

package main

import (
  "code.google.com/p/gosqlite/sqlite"
  "github.com/keep94/gofunctional3/functional"
)

func main() {
  conn, _ := sqlite.Open("YourDataFilePath")
      defer conn.Close()
  stmt, _ := conn.Prepare("select * from People")
      defer stmt.Finalize()
  s := functional.ReadRows(stmt)
  s = functional.Slice(s, 3 * 25, 4 * 25)
      var person Person
      err := s.Next(&person)
      for ; err == nil; err = s.Next(&person) {
        // Display person here
      }
      if err != functional.Done {
        // Do error handling here
      }
    }

Like python iterators and generators, Stream types are lazily evaluated, so the above code will read only the first 100 names no matter how many people are in the database.

See tests and documentation for detailed usage.