parser: add initial Parser emitting non-whitespace tokens

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

parser/token.go

@@ -0,0 +1,31 @@
+package parser
+
+//go:generate go run golang.org/x/tools/cmd/stringer -type=TokenType
+
+// A TokenType is a type of Token
+type TokenType uint
+
+const (
+	// TokenUnknown represents a Token that hasn't been identified
+	TokenUnknown TokenType = iota
+	// TokenSectionStart indicates the opening marker of a section declaration.
+	// The left squared bracket.
+	TokenSectionStart
+	// TokenSectionEnd indicates the closing marker of a section declaration.
+	// The right squared bracket.
+	TokenSectionEnd
+	// 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
+)