parser: introduce Token and TokenType enum

Signed-off-by: Alejandro Mery <amery@jpi.io>

go.mod

@@ -5,6 +5,7 @@ go 1.19
 require (
 	asciigoat.org/core v0.3.6
 	github.com/mgechev/revive v1.3.3
+	golang.org/x/tools v0.12.0
 )
 
 require (
@@ -19,6 +20,6 @@ require (
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/olekukonko/tablewriter v0.0.5 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
+	golang.org/x/mod v0.12.0 // indirect
 	golang.org/x/sys v0.11.0 // indirect
-	golang.org/x/tools v0.12.0 // indirect
 )

go.sum

@@ -38,6 +38,8 @@ github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
+golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.11.0 h1:eG7RXZHdqOJ1i+0lgLgCpSXAp6M3LYlAo6osgSi0xOM=

parser/token.go

@@ -0,0 +1,41 @@
+package parser
+
+//go:generate go run golang.org/x/tools/cmd/stringer -type=TokenType
+import (
+	"fmt"
+
+	"asciigoat.org/core/lexer"
+)
+
+// A TokenType is a type of Token
+type TokenType uint
+
+const (
+	// TokenUnknown represents a Token that hasn't been identified
+	TokenUnknown TokenType = iota
+	// TokenSectionName represents the section name between the squared brackets
+	TokenSectionName
+	// TokenSectionSubname represents a secondary name in the section represented
+	// between quotes after the section name.
+	// e.g.
+	// [section_name "section_subname"]
+	TokenSectionSubname
+	// TokenComment represents a comment, including the initial ';' or '#' until
+	// the end of the line
+	TokenComment
+	// TokenFieldKey represents a field name in a `key = value` entry
+	TokenFieldKey
+	// TokenFieldValue represents a field value in a `key = value` entry
+	TokenFieldValue
+)
+
+// A Token is an element from the document
+type Token struct {
+	Type     TokenType
+	Position lexer.Position
+	Value    string
+}
+
+func (t Token) String() string {
+	return fmt.Sprintf("%s:%v:%v: %q", t.Type, t.Position.Line, t.Position.Column, t.Value)
+}

parser/tokentype_string.go

@@ -0,0 +1,28 @@
+// Code generated by "stringer -type=TokenType"; DO NOT EDIT.
+
+package parser
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[TokenUnknown-0]
+	_ = x[TokenSectionName-1]
+	_ = x[TokenSectionSubname-2]
+	_ = x[TokenComment-3]
+	_ = x[TokenFieldKey-4]
+	_ = x[TokenFieldValue-5]
+}
+
+const _TokenType_name = "TokenUnknownTokenSectionNameTokenSectionSubnameTokenCommentTokenFieldKeyTokenFieldValue"
+
+var _TokenType_index = [...]uint8{0, 12, 28, 47, 59, 72, 87}
+
+func (i TokenType) String() string {
+	if i >= TokenType(len(_TokenType_index)-1) {
+		return "TokenType(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _TokenType_name[_TokenType_index[i]:_TokenType_index[i+1]]
+}

tools/tools.go

@@ -4,4 +4,5 @@ package tools
 
 import (
 	_ "github.com/mgechev/revive"
+	_ "golang.org/x/tools/cmd/stringer"
 )