RosettaCodeData/Task/Textonyms/Go/textonyms.go

142 lines
3.3 KiB
Go

package main
import (
"bufio"
"flag"
"fmt"
"io"
"log"
"os"
"strings"
"unicode"
)
func main() {
log.SetFlags(0)
log.SetPrefix("textonyms: ")
wordlist := flag.String("wordlist", "wordlist", "file containing the list of words to check")
flag.Parse()
if flag.NArg() != 0 {
flag.Usage()
os.Exit(2)
}
t := NewTextonym(phoneMap)
_, err := ReadFromFile(t, *wordlist)
if err != nil {
log.Fatal(err)
}
t.Report(os.Stdout, *wordlist)
}
// phoneMap is the digit to letter mapping of a typical phone.
var phoneMap = map[byte][]rune{
'2': []rune("ABC"),
'3': []rune("DEF"),
'4': []rune("GHI"),
'5': []rune("JKL"),
'6': []rune("MNO"),
'7': []rune("PQRS"),
'8': []rune("TUV"),
'9': []rune("WXYZ"),
}
// ReadFromFile is a generic convience function that allows the use of a
// filename with an io.ReaderFrom and handles errors related to open and
// closing the file.
func ReadFromFile(r io.ReaderFrom, filename string) (int64, error) {
f, err := os.Open(filename)
if err != nil {
return 0, err
}
n, err := r.ReadFrom(f)
if cerr := f.Close(); err == nil && cerr != nil {
err = cerr
}
return n, err
}
type Textonym struct {
numberMap map[string][]string // map numeric string into words
letterMap map[rune]byte // map letter to digit
count int // total number of words in numberMap
textonyms int // number of numeric strings with >1 words
}
func NewTextonym(dm map[byte][]rune) *Textonym {
lm := make(map[rune]byte, 26)
for d, ll := range dm {
for _, l := range ll {
lm[l] = d
}
}
return &Textonym{letterMap: lm}
}
func (t *Textonym) ReadFrom(r io.Reader) (n int64, err error) {
t.numberMap = make(map[string][]string)
buf := make([]byte, 0, 32)
sc := bufio.NewScanner(r)
sc.Split(bufio.ScanWords)
scan:
for sc.Scan() {
buf = buf[:0]
word := sc.Text()
// XXX we only bother approximating the number of bytes
// consumed. This isn't used in the calling code and was
// only included to match the io.ReaderFrom interface.
n += int64(len(word)) + 1
for _, r := range word {
d, ok := t.letterMap[unicode.ToUpper(r)]
if !ok {
//log.Printf("ignoring %q\n", word)
continue scan
}
buf = append(buf, d)
}
//log.Printf("scanned %q\n", word)
num := string(buf)
t.numberMap[num] = append(t.numberMap[num], word)
t.count++
if len(t.numberMap[num]) == 2 {
t.textonyms++
}
//log.Printf("%q → %v\t→ %v\n", word, num, t.numberMap[num])
}
return n, sc.Err()
}
func (t *Textonym) Most() (most int, subset map[string][]string) {
for k, v := range t.numberMap {
switch {
case len(v) > most:
subset = make(map[string][]string)
most = len(v)
fallthrough
case len(v) == most:
subset[k] = v
}
}
return most, subset
}
func (t *Textonym) Report(w io.Writer, name string) {
// Could be fancy and use text/template package but fmt is sufficient
fmt.Fprintf(w, `
There are %v words in %q which can be represented by the digit key mapping.
They require %v digit combinations to represent them.
%v digit combinations represent Textonyms.
`,
t.count, name, len(t.numberMap), t.textonyms)
n, sub := t.Most()
fmt.Fprintln(w, "\nThe numbers mapping to the most words map to",
n, "words each:")
for k, v := range sub {
fmt.Fprintln(w, "\t", k, "maps to:", strings.Join(v, ", "))
}
}