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lexfuncs.go
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lexfuncs.go
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package main
import "bytes"
import "strings"
import . "github.com/conlang-software-dev/Logopoeist/lexer"
func commentState(in *RuneBuffer, out chan *Item) StateFn {
for {
r, ok := in.Next()
if !ok || r == '\n' {
break
}
}
return switchState
}
func numberState(in *RuneBuffer, out chan *Item) StateFn {
buf := new(bytes.Buffer)
for {
r, ok, more := in.Accept("0123456789.")
if !(more && ok) {
break
}
buf.WriteRune(r)
}
out <- &Item{Type: "number", Token: buf.String()}
return switchState
}
func symbolState(in *RuneBuffer, out chan *Item) StateFn {
buf := new(bytes.Buffer)
for {
r, ok, _ := in.AcceptNot(" \t\r\n;*<>-!=")
if !ok {
break
}
buf.WriteRune(r)
}
out <- &Item{Type: "symbol", Token: buf.String()}
return switchState
}
func arrowState(in *RuneBuffer, out chan *Item) StateFn {
first, _ := in.Next()
second, _ := in.Next()
out <- &Item{Type: "arrow", Token: string([]rune{first, second})}
return switchState
}
func phonemeState(in *RuneBuffer, out chan *Item) StateFn {
buf := new(bytes.Buffer)
for {
r, ok, _ := in.AcceptNot(" \t\r\n*>")
if !ok {
break
}
if r == '\\' { // escape character
in.Next()
r, ok = in.Next()
if !ok {
break
}
}
buf.WriteRune(r)
}
out <- &Item{Type: "phoneme", Token: buf.String()}
return setState
}
func setState(in *RuneBuffer, out chan *Item) StateFn {
if r, ok := in.Peek(); ok {
switch {
case strings.IndexRune(" \t\r\n", r) >= 0:
for ok { //skip whitespace
_, ok, _ = in.Accept(" \t\r\n")
}
return setState
case strings.IndexRune("*/", r) >= 0:
in.Next()
out <- &Item{Type: string(r), Token: string(r)}
return setState
case strings.IndexRune("0123456789", r) >= 0:
numberState(in, out)
return setState
case r == ';':
in.Next()
out <- &Item{Type: "EOL", Token: "EOL"}
commentState(in, out)
return setState
case r == '>':
in.Next()
out <- &Item{Type: ">", Token: ">"}
return switchState
default:
return phonemeState
}
} else {
return nil
}
}
func switchState(in *RuneBuffer, out chan *Item) StateFn {
if r, ok := in.Peek(); ok {
for ok { // skip spaces
_, ok, _ = in.Accept(" \t\r")
}
switch {
case strings.IndexRune(" \t\r", r) >= 0:
for ok { // skip whitespace
_, ok, _ = in.Accept(" \t\r")
}
return switchState
case r == '\n':
in.Next()
out <- &Item{Type: "EOL", Token: "EOL"}
return switchState
case r == ';':
in.Next()
out <- &Item{Type: "EOL", Token: "EOL"}
return commentState
case strings.IndexRune("#$_*/=", r) >= 0:
in.Next()
out <- &Item{Type: string(r), Token: string(r)}
return switchState
case r == '<':
in.Next()
out <- &Item{Type: "<", Token: "<"}
return setState
case strings.IndexRune("-!", r) >= 0:
return arrowState
case strings.IndexRune("0123456789", r) >= 0:
return numberState
default:
return symbolState
}
}
out <- &Item{Type: "EOF", Token: "EOF"}
return nil
}