parser: implement initial tokeniser

only logging position, errors and non-whitespace elements

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

go.mod

@@ -3,7 +3,7 @@ module asciigoat.org/ini
 go 1.19
 
 require (
-	asciigoat.org/core v0.3.4
+	asciigoat.org/core v0.3.6
 	github.com/mgechev/revive v1.3.3
 )
 

go.sum

@@ -1,5 +1,5 @@
-asciigoat.org/core v0.3.4 h1:FQ4IvqQS7T1wke0dOeKUABtNY+JQHmccmedBjz18j9s=
-asciigoat.org/core v0.3.4/go.mod h1:tXj+JUutxRbcO40ZQRuUVaZ4rnYz1kAZ0nblisV8u74=
+asciigoat.org/core v0.3.6 h1:b1vL090OxylmSOwLQryjrmC8FhhCtktMyeJSy1e6LwI=
+asciigoat.org/core v0.3.6/go.mod h1:tXj+JUutxRbcO40ZQRuUVaZ4rnYz1kAZ0nblisV8u74=
 github.com/BurntSushi/toml v1.3.2 h1:o7IhLm0Msx3BaB+n3Ag7L8EVlByGnpq14C4YWiu/gL8=
 github.com/BurntSushi/toml v1.3.2/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=
 github.com/chavacava/garif v0.0.0-20230608123814-4bd63c2919ab h1:5JxePczlyGAtj6R1MUEFZ/UFud6FfsOejq7xLC2ZIb0=

parser/lexer.go

@@ -51,16 +51,28 @@ func (p *Parser) lexNewLine(r1 rune) {
 	// r1 is warrantied to be either \n or \r
 	r2, _, err := p.src.ReadRune()
 
-	switch {
-	case r1 == '\r' && r2 == '\n':
-		// CR LN
-	case r1 == '\r' && err == nil:
-		// CR
-		p.src.UnreadRune()
-	case r2 == '\r':
-		// LN CR
-	case err == nil:
-		// LN
-		p.src.UnreadRune()
+	switch r1 {
+	case '\r':
+		switch {
+		case r2 == '\n':
+			// CR LN
+		case err == nil:
+			// CR
+			p.src.UnreadRune()
+		default:
+			// CR EOF
+		}
+	case '\n':
+		switch {
+		case r2 == '\r':
+			// LN CR
+		case err == nil:
+			// LN
+			p.src.UnreadRune()
+		default:
+			// LN EOF
+		}
+	default:
+		panic("unreachable")
 	}
 }