Implement lexer based on Scanner

We also add the skeleton of a recursive descent parser.

2 files changed, 49 insertions, 25 deletions

diff --git a/conf/parser.go b/conf/parser.go
new file mode 100644
index 0000000..21bc604
--- /dev/null
+++ b/conf/parser.go
@@ -0,0 +1,28 @@
+package conf
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+// Having a Config to Manager function could be nice?
+// Or we could just return a Manager from here.
+type Config struct {
+}
+
+type parser struct {
+	scanner
+}
+
+func NewConfig(r io.Reader) *Config {
+	s := newScanner(r)
+	tt, tok, err := s.Next()
+	for err == nil {
+		fmt.Fprintf(os.Stderr, "tokentype: %d, token: %q, err: %v\n", tt, tok, err)
+		tt, tok, err = s.Next()
+	}
+	fmt.Fprintf(os.Stderr, "Error: tokentype: %d, token: %q, err: %v\n", tt, tok, err)
+
+	return &Config{}
+}
diff --git a/conf/scanner.go b/conf/scanner.go
index fd2a3cf..172103f 100644
--- a/conf/scanner.go
+++ b/conf/scanner.go
@@ -5,62 +5,58 @@ import (
 	"io"
 )
 
-type token int
+type tokentype int
 
 const (
-	Name        token = iota
-	Delimiter   token = iota
-	Nothing     token = iota
-	IfStatement token = iota
+	Name tokentype = iota
+	Literal
+	Delimiter
+	Nothing
+	IfStatement
 )
 
-// Having a Config to Manager function could be nice?
-// Or we could just return a Manager from here.
-type Config struct {
+type token struct {
+	Type tokentype
 }
 
 type scanner struct {
 	r    io.Reader
-	ss   bufio.Scanner
+	bs   bufio.Scanner
 	prev token
 	cur  token
 }
 
-func NewConfig(r io.Reader) *Config {
-	br := bufio.NewReader(r)
-	s := newScanner(br)
-	s.next()
-
-	return &Config{}
-}
-
 func newScanner(r io.Reader) *scanner {
 	ns := bufio.NewScanner(r)
 	ns.Split(bufio.ScanWords)
 
 	sc := scanner{
 		r:  r,
-		ss: *ns,
+		bs: *ns,
 	}
 
 	return &sc
 }
 
-func getTokenType(s string) token {
+func getTokenType(s string) tokentype {
 	return Nothing
 }
 
-func (s *scanner) next() (token, string, error) {
-	stop := s.ss.Scan()
-	if stop {
-		return Nothing, "", s.ss.Err()
+func (s *scanner) Next() (tokentype, string, error) {
+	more := s.bs.Scan()
+	if !more {
+		err := s.bs.Err()
+		if err != nil {
+			return Nothing, "", err
+		}
+		return Nothing, "", io.EOF
 	}
-	tokstr := s.ss.Text()
+	tokstr := s.bs.Text()
 	token := getTokenType(tokstr)
 
 	return token, tokstr, nil
 }
 
-func (s *scanner) peek() (token, string, error) {
+func (s *scanner) peek() (tokentype, string, error) {
 	return Nothing, "", nil
 }