parser: introduce Token and TokenType enum

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

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("%v:%v: %s: %q", t.Position.Line, t.Position.Column, t.Type, 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]]
+}