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|
package mintage
import (
"bufio"
"fmt"
"io"
"strconv"
"strings"
"unicode"
)
const (
_ = -iota
Unknown // Unknown mintage
Invalid // All mintages <= than this are invalid
)
type SyntaxError struct {
expected, got string
file string
linenr int
}
func (e SyntaxError) Error() string {
return fmt.Sprintf("%s:%d: syntax error: expected %s but got %s",
e.file, e.linenr, e.expected, e.got)
}
type Row struct {
Year int
Mintmark string
Cols [8]int
}
type Set struct {
StartYear int
Circ, BU, Proof []Row
}
func (r Row) Label() string {
if r.Mintmark != "" {
return fmt.Sprintf("%d %s", r.Year, r.Mintmark)
}
return strconv.Itoa(r.Year)
}
func Parse(reader io.Reader, file string) (Set, error) {
var (
data Set // Our data struct
slice *[]Row // Where to append mintages
)
scanner := bufio.NewScanner(reader)
for linenr := 1; scanner.Scan(); linenr++ {
var mintmark struct {
s string
star bool
}
line := scanner.Text()
tokens := strings.FieldsFunc(strings.TrimSpace(line), unicode.IsSpace)
switch {
case len(tokens) == 0:
continue
case tokens[0] == "BEGIN":
if len(tokens)-1 != 1 {
return Set{}, SyntaxError{
expected: "single argument to ‘BEGIN’",
got: fmt.Sprintf("%d arguments", len(tokens)-1),
file: file,
linenr: linenr,
}
}
arg := tokens[1]
switch arg {
case "CIRC":
slice = &data.Circ
case "BU":
slice = &data.BU
case "PROOF":
slice = &data.Proof
default:
if !isNumeric(arg, false) {
return Set{}, SyntaxError{
expected: "‘CIRC’, ‘BU’, ‘PROOF’, or a year",
got: arg,
file: file,
linenr: linenr,
}
}
data.StartYear, _ = strconv.Atoi(arg)
}
case isLabel(tokens[0]):
n := len(tokens[0])
if n > 2 && tokens[0][n-2] == '*' {
mintmark.star = true
mintmark.s = tokens[0][:n-2]
} else {
mintmark.s = tokens[0][:n-1]
}
tokens = tokens[1:]
if !isNumeric(tokens[0], true) && tokens[0] != "?" {
return Set{}, SyntaxError{
expected: "mintage row after label",
got: tokens[0],
file: file,
linenr: linenr,
}
}
fallthrough
case isNumeric(tokens[0], true), tokens[0] == "?":
switch {
case slice == nil:
return Set{}, SyntaxError{
expected: "coin type declaration",
got: tokens[0],
file: file,
linenr: linenr,
}
case data.StartYear == 0:
return Set{}, SyntaxError{
expected: "start year declaration",
got: tokens[0],
file: file,
linenr: linenr,
}
}
numcoins := len(Row{}.Cols)
tokcnt := len(tokens)
if tokcnt != numcoins {
word := "entries"
if tokcnt == 1 {
word = "entry"
}
return Set{}, SyntaxError{
expected: fmt.Sprintf("%d mintage entries", numcoins),
got: fmt.Sprintf("%d %s", tokcnt, word),
file: file,
linenr: linenr,
}
}
row := Row{Mintmark: mintmark.s}
if len(*slice) == 0 {
row.Year = data.StartYear
} else {
row.Year = (*slice)[len(*slice)-1].Year
if row.Mintmark == "" || mintmark.star {
row.Year++
}
}
for i, tok := range tokens {
if tok == "?" {
row.Cols[i] = Unknown
} else {
row.Cols[i] = atoiWithDots(tok)
}
}
*slice = append(*slice, row)
default:
return Set{}, SyntaxError{
expected: "‘BEGIN’ directive or mintage row",
got: fmt.Sprintf("invalid token ‘%s’", tokens[0]),
file: file,
linenr: linenr,
}
}
}
return data, nil
}
func isNumeric(s string, dot bool) bool {
for _, ch := range s {
switch ch {
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
default:
if ch != '.' || !dot {
return false
}
}
}
return true
}
func isLabel(s string) bool {
n := len(s)
return (n > 2 && s[n-1] == ':' && s[n-2] == '*') ||
(n > 1 && s[n-1] == ':')
}
func atoiWithDots(s string) int {
n := 0
for _, ch := range s {
if ch == '.' {
continue
}
n = n*10 + int(ch) - '0'
}
return n
}
|
