Merge branch 'writeownscanner'

This is not working correctly yet.

2 files changed, 131 insertions, 13 deletions

diff --git a/conf/parser.go b/conf/parser.go
index 4f58713..3d584f6 100644
--- a/conf/parser.go
+++ b/conf/parser.go
@@ -1,8 +1,12 @@
 // grammar of the config file
 //
+// Notes: We parse exactly three modules ("input", "filter", "output")
+// in our configuration. Each module consists of two name-object pairs
+// that are nested. We don't want to allow limitless recursion here.
+//
 // config = module module module
-// module = name object
-// name = 'input' | 'filter' | 'etc.'
+// module = name object name object
+// name = 'input' | 'filter' | 'output' | etc.
 // object = '{' keyvalue | keyvalue | ... '}'
 // keyvalue = statement '=>' value
 // statement = name | if
@@ -17,8 +21,8 @@ import (
 	"os"
 )
 
-// Having a Config to Manager function could be nice?
-// Or we could just return a Manager from here.
+// Having a Config to Manager function could be nice?  Or we could just
+// return a Manager from here which may be even better...
 type Config struct {
 }
 
@@ -44,6 +48,13 @@ func NewConfig(r io.Reader) *Config {
 }
 
 func (p *parser) startparsing() {
+	p.module("input")
+
+	p.module("filter")
+
+}
+
+func (p *parser) advanceOneToken(place string) {
 	var err error
 
 	p.last = p.cur
@@ -56,8 +67,82 @@ func (p *parser) startparsing() {
 	fmt.Fprintf(os.Stderr, "Error: tokentype: %v, token: %q, err: %v\n", p.cur.Type, p.cur.Lit, err)
 }
 
-func (p *parser) module(name string) {
+func (p *parser) module(firstname string) {
+	p.advanceOneToken("module")
+
+	fmt.Fprintf(os.Stderr, "tokentype: %d, token: %q\n", p.cur.Type, p.cur.Lit)
+
+	if p.cur.Lit != firstname {
+		fmt.Fprintf(os.Stderr, "error when parsing module. We were expecting name %q but got %q at line %d offset %d.\n", firstname, p.cur.Lit, p.cur.LineNr, p.cur.Offset)
+	}
+
+	p.advanceOneToken("module")
+	if p.cur.Type != ObjectOpen {
+		fmt.Fprintf(os.Stderr, "error when parsing module. We were expecting an opening bracket but got %q at line %d offset %d.\n", p.cur.Lit, p.cur.LineNr, p.cur.Offset)
+	}
+
+	p.advanceOneToken("module")
+	if p.cur.Type != Name {
+		fmt.Fprintf(os.Stderr, "error when parsing module. We were expecting another name but got %q at line %d offset %d.\n", p.cur.Lit, p.cur.LineNr, p.cur.Offset)
+	}
+	p.object()
+
+	p.advanceOneToken("module")
+	if p.cur.Lit[0] != '}' {
+		fmt.Fprintf(os.Stderr, "error when parsing module. Was expecting a closing bracket but got %s at line %d offset %d.\n", p.cur.Lit, p.cur.LineNr, p.cur.Offset)
+	}
+
 }
 
 func (p *parser) object() {
+	p.advanceOneToken("object")
+
+	if p.cur.Lit[0] != '{' {
+		fmt.Fprintf(os.Stderr, "error when parsing object. Was expecting an opening bracket but got %s at line %d offset %d.\n", p.cur.Lit, p.cur.LineNr, p.cur.Offset)
+	}
+	// hack to deal with case where there is no white space between
+	// the delimiters.
+	if p.cur.Lit == "{}" {
+		return
+	}
+
+	for {
+		more := p.keyvalue()
+		if !more {
+			break
+		}
+	}
+}
+
+func (p *parser) keyvalue() bool {
+	p.advanceOneToken("keyvalue")
+
+	fmt.Fprintf(os.Stderr, "keyvalue: tokentype: %d, token: %q\n", p.cur.Type, p.cur.Lit)
+	if p.cur.Type != Literal {
+		fmt.Fprintf(os.Stderr, "error when parsing keyvalue. Was expecting a name but got %q at line %d offset %d.\n", p.cur.Lit, p.cur.LineNr, p.cur.Offset)
+	}
+
+	p.advanceOneToken("keyvalue")
+	if p.cur.Lit != "=>" {
+		fmt.Fprintf(os.Stderr, "error when parsing keyvalue. Was expecting a '=>' but got %q at line %d offset %d.\n", p.cur.Lit, p.cur.LineNr, p.cur.Offset)
+	}
+
+	p.advanceOneToken("keyvalue")
+	if p.cur.Type != Literal && p.cur.Type != Name {
+		fmt.Fprintf(os.Stderr, "error when parsing keyvalue. Was expecting a literal or a name but got %q at line %d offset %d.\n", p.cur.Lit, p.cur.LineNr, p.cur.Offset)
+	}
+
+	tok, err := p.s.Peek()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error when parsing keyvalue. Got an error when checking if there are more keyvalues: %v.\n", err)
+		return false
+	}
+
+	fmt.Fprintf(os.Stderr, "peeked %q (type %d) at line %d offset %d.\n", tok.Lit, tok.Type, tok.LineNr, tok.Offset)
+	if tok.Type == ObjectClose {
+		p.advanceOneToken("keyvaluelast")
+		return false
+	}
+
+	return true
 }
diff --git a/conf/scanner.go b/conf/scanner.go
index 54546aa..975a8e4 100644
--- a/conf/scanner.go
+++ b/conf/scanner.go
@@ -14,15 +14,19 @@ type tokentype int
 const (
 	Name tokentype = iota
 	Literal
-	DeliOpen
-	DeliClose
+	ListOpen
+	ListClose
+	ObjectOpen
+	ObjectClose
+	EmptyList
+	EmptyObject
 	Nothing
 	IfStatement
 )
 
 var tokentypestrings []string = []string{Name: "Name", Literal: "Literal",
-	DeliOpen: "Opening delimiter", DeliClose: "Closing delimiter",
-	Nothing: "Nothing", IfStatement: "If statement"}
+	ListOpen: "List Open", ListClose: "List Close", ObjectOpen: "Object Open",
+	ObjectClose: "Object Close", Nothing: "Nothing", IfStatement: "If statement"}
 
 func (tt tokentype) String() string {
 	return tokentypestrings[tt]
@@ -39,6 +43,8 @@ type scanner struct {
 	data    []byte
 	offset  int
 	curline int
+
+	peeked *token
 }
 
 func newScanner(r io.Reader) *scanner {
@@ -58,18 +64,36 @@ func newScanner(r io.Reader) *scanner {
 }
 
 func getTokenType(s []byte) tokentype {
-	return Nothing
+	switch s[0] {
+	case '"', '\'':
+		return Literal
+	case '[':
+		return ListOpen
+	case ']':
+		return ListClose
+	case '{':
+		return ObjectOpen
+	case '}':
+		return ObjectClose
+	}
+
+	return Name
 }
 
 func (s *scanner) Scan() (token, error) {
 	processed := 0
 	tokenstarted := false
 	oldline := s.curline
+	if s.peeked != nil {
+		ret := *s.peeked
+		s.peeked = nil
+		return ret, nil
+	}
 	for {
 		r, rlen := utf8.DecodeRune(s.data[s.offset+processed:])
 		if r == utf8.RuneError {
 			if rlen == 1 {
-				return token{}, fmt.Errorf("found invalid UTF8 at offset %d, before: %s", s.offset, s.data[s.offset])
+				return token{}, fmt.Errorf("found invalid UTF8 at offset %d, before: %s", s.offset, string(s.data[s.offset]))
 			} else if rlen == 0 {
 				return token{}, io.EOF
 			}
@@ -105,6 +129,15 @@ func (s *scanner) Scan() (token, error) {
 	return ret, nil
 }
 
-func (s *scanner) peek() (tokentype, string, error) {
-	return Nothing, "", nil
+func (s *scanner) Peek() (token, error) {
+	if s.peeked != nil {
+		return *s.peeked, nil
+	}
+
+	tok, err := s.Scan()
+	if err != nil {
+		return token{}, err
+	}
+	s.peeked = &tok
+	return tok, nil
 }