/
sc.go
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/
sc.go
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package tier
import (
"fmt"
"github.com/kpmy/ypk/assert"
"io"
"strconv"
"strings"
"unicode"
)
type SymCode int
const (
None SymCode = iota
Ident
Number
String
UserIota = 100
)
type Symbol struct {
Code SymCode
Value string
StringOpts struct {
Apos bool
}
NumberOpts struct {
Modifier string
Period bool
}
}
type Opts struct {
IdentMap map[string]SymCode
IdentStarts func() string
IdentContains func() string
NumContains func() string
NumModifiers func() string
SpaceMap map[string]SymCode
CombinedMap map[string]SymCode
CommentTriplet [3]rune
Skip func(r rune) bool
NoStrings bool
NoNum bool
}
type Scanner interface {
Get() Symbol
Error() error
Count() int
Pos() (int, int)
}
func Token2(r rune) string {
return string([]rune{r})
}
func Token(r rune) string {
if unicode.IsSpace(r) || int(r) <= int(' ') {
return strconv.Itoa(int(r)) + "U"
} else {
return string([]rune{r})
}
}
func (s Symbol) String() string {
return fmt.Sprint("sym: `", s.Code, "` ", s.Value)
}
func (sym SymCode) String() (s string) {
switch sym {
case None:
s = "none"
case Ident:
s = "ident"
case Number:
s = "num"
case String:
s = "string"
default:
s = strconv.Itoa(int(sym))
}
return
}
type sc struct {
rd io.RuneReader
err error
ch rune
pos int
opts Opts
lines struct {
count int
last int
crlf bool
lens map[int]func() (int, int)
}
}
func (s *sc) Count() int { return s.pos }
func (s *sc) Pos() (int, int) { return s.lines.count, s.lines.last }
func (s *sc) Get() (sym Symbol) {
for stop := s.err != nil; !stop; {
sym = s.get()
stop = sym.Code != 0 || s.err != nil
}
return
}
func (s *sc) Error() error {
return s.err
}
func (s *sc) mark(msg ...interface{}) {
//log.Println("at pos ", s.pos, " ", fmt.Sprintln(msg...))
l, c := s.Pos()
panic(Err("scanner", s.Count(), l, c, msg...))
}
func (o Opts) safeIdentContains() string {
if o.IdentContains != nil {
return o.IdentContains()
}
return ""
}
func (o Opts) safeIdentStarts() string {
if o.IdentStarts != nil {
return o.IdentStarts()
}
return ""
}
func (o Opts) safeNumContains() string {
if o.NumContains != nil {
return o.NumContains()
}
return ""
}
func (o Opts) safeNumModifiers() string {
if o.NumContains != nil {
return o.NumModifiers()
}
return ""
}
func (o Opts) safeSkip(r rune) (skip bool) {
if o.Skip != nil {
skip = o.Skip(r)
}
return
}
func (o Opts) isIdentLetter(r rune) bool {
return o.isIdentFirstLetter(r) || unicode.IsDigit(r) || strings.ContainsRune(o.safeIdentContains(), r)
}
func (o Opts) isIdentFirstLetter(r rune) bool {
return unicode.IsLetter(r) || strings.ContainsRune(o.safeIdentStarts(), r)
}
func (o Opts) validate() {
assert.For(o.CommentTriplet[0] != o.CommentTriplet[1], 20)
assert.For(o.CommentTriplet[1] != o.CommentTriplet[2], 20)
}
func (s *sc) ident() (sym Symbol) {
assert.For(s.opts.isIdentFirstLetter(s.ch), 20, "letter must be first")
buf := make([]rune, 0)
for s.err == nil && s.opts.isIdentLetter(s.ch) {
buf = append(buf, s.ch)
s.next()
}
if s.err == nil || s.err == io.EOF {
sym.Value = string(buf)
if code, ok := s.opts.IdentMap[sym.Value]; ok {
sym.Code = code
} else {
sym.Code = Ident
}
} else {
s.mark("error while reading ident ", s.err)
}
return
}
const dec = "0123456789"
//first char always 0..9
func (s *sc) num() (sym Symbol) {
assert.For(unicode.IsDigit(s.ch), 20, "digit expected")
var buf []rune
var mbuf []rune
hasDot := false
for {
buf = append(buf, s.ch)
s.next()
if s.ch == '.' {
if !hasDot {
hasDot = true
} else if hasDot {
s.mark("dot unexpected")
}
}
if s.err != nil || !(s.ch == '.' || strings.ContainsRune(dec, s.ch) || strings.ContainsRune(s.opts.safeNumContains(), s.ch)) {
break
}
}
if strings.ContainsRune(s.opts.safeNumModifiers(), s.ch) {
mbuf = append(mbuf, s.ch)
s.next()
}
if strings.ContainsAny(string(buf), s.opts.safeNumContains()) && len(mbuf) == 0 {
s.mark("modifier expected")
}
if s.err == nil || s.err == io.EOF {
sym.Code = Number
sym.Value = string(buf)
sym.NumberOpts.Modifier = string(mbuf)
sym.NumberOpts.Period = hasDot
} else {
s.mark("error reading number")
}
return
}
func (s *sc) str() string {
assert.For(s.ch == '"' || s.ch == '\'' || s.ch == '`', 20, "quote expected")
var buf []rune
ending := s.ch
s.next()
for ; s.err == nil && s.ch != ending; s.next() {
buf = append(buf, s.ch)
}
if s.err == nil {
s.next()
} else {
s.mark("string expected")
}
return string(buf)
}
func (s *sc) next() rune {
read := 0
s.ch, read, s.err = s.rd.ReadRune()
if s.err == nil {
s.pos += read
}
if s.ch == '\r' || s.ch == '\n' {
s.line()
} else {
s.lines.last++
}
//log.Println(Token(s.ch), s.err)
return s.ch
}
func (s *sc) line() {
if s.ch == '\r' {
s.lines.crlf = true
}
if (s.lines.crlf && s.ch == '\r') || (!s.lines.crlf && s.ch == '\n') {
s.lines.lens[s.lines.count] = func() (int, int) {
return s.lines.count, s.pos
}
s.lines.count++
s.lines.last = 1
} else if s.lines.crlf && s.ch == '\n' {
s.lines.last--
}
}
func (s *sc) comment() {
assert.For(s.ch == '*', 20, "expected ", s.opts.CommentTriplet[1], "got ", Token(s.ch))
for {
for s.err == nil && s.ch != s.opts.CommentTriplet[1] {
if s.ch == s.opts.CommentTriplet[0] {
if s.next() == s.opts.CommentTriplet[1] {
s.comment()
}
} else {
s.next()
}
}
for s.err == nil && s.ch == s.opts.CommentTriplet[1] {
s.next()
}
if s.err != nil || s.ch == s.opts.CommentTriplet[2] {
break
}
}
if s.err == nil {
s.next()
} else {
s.mark("unclosed comment")
}
}
func (s *sc) filter(r ...rune) SymCode {
var run func(keys map[string]SymCode, r ...rune) SymCode
run = func(keys map[string]SymCode, r ...rune) (ret SymCode) {
key := string(r)
ret = keys[key]
continues := make(map[string]SymCode)
for k, v := range keys {
if key != k && strings.HasPrefix(k, key) {
continues[k] = v
}
}
//log.Println(ret, continues)
if len(continues) > 0 {
nr := []rune(key)
nr = append(nr, s.next())
if x := run(continues, nr...); x != None {
ret = x
}
}
return
}
return run(s.opts.CombinedMap, r...)
}
func (s *sc) get() (sym Symbol) {
justRune := func() {
if symCode := s.filter(s.ch); symCode != None {
sym.Code = symCode
s.next()
} else {
if !s.opts.safeSkip(s.ch) {
s.mark("unhandled ", "`", Token(s.ch), "`")
}
s.next()
}
}
switch s.ch {
case s.opts.CommentTriplet[0]:
if s.next() == s.opts.CommentTriplet[1] {
s.comment()
} else if symCode := s.filter(s.opts.CommentTriplet[0], s.ch); symCode != None {
sym.Code = symCode
} else {
sym.Code = s.filter(s.opts.CommentTriplet[0])
}
case '"', '\'', '`':
if !s.opts.NoStrings {
sym.StringOpts.Apos = (s.ch == '\'' || s.ch == '`')
sym.Value = s.str()
sym.Code = String
} else {
justRune()
}
default:
switch {
case s.opts.isIdentFirstLetter(s.ch):
sym = s.ident()
case unicode.IsSpace(s.ch):
sym.Value = Token2(s.ch)
sym.Code, _ = s.opts.SpaceMap[sym.Value]
s.next()
case unicode.IsDigit(s.ch):
if !s.opts.NoNum {
sym = s.num()
} else {
justRune()
}
default:
justRune()
}
}
return
}
func NewScanner(rd io.RuneReader, opts ...Opts) Scanner {
ret := &sc{}
ret.rd = rd
ret.lines.lens = make(map[int]func() (int, int))
ret.lines.count++
if len(opts) > 0 {
ret.opts = opts[0]
} else {
ret.opts = DefaultOpts
}
ret.opts.validate()
ret.next()
return ret
}
var DefaultOpts Opts
func init() {
DefaultOpts.IdentMap = make(map[string]SymCode)
DefaultOpts.SpaceMap = make(map[string]SymCode)
DefaultOpts.NumContains = func() string { return "ABCDEF" }
DefaultOpts.NumModifiers = func() string { return "U" }
DefaultOpts.CombinedMap = make(map[string]SymCode)
DefaultOpts.CommentTriplet = [3]rune{'(', '*', ')'}
}