state: convert ElementState to flags, easily check legal attr placement

Compiler.ps1

···
 	ILLEGAL # idk
 }
 
-enum ElementState {
-	UNOPENED               = 0 # before <
-	OPENED                 = 1 # <
-	AFTER_TAG              = 2 # <div
-	AFTER_ATTRIBUTE_NAME   = 3 # <div attr
-	AFTER_ATTRIBUTE_EQUALS = 4 # <div attr=
-	AFTER_ATTRIBUTE_VALUE  = 5 # <div attr=val, <div
-	CLOSED                 = 6 # <div ...>
-	CLOSED_VOID            = 7 # <div .../>
+[Flags()] enum ElementState {
+	UNOPENED               = 1   # before <
+	OPENED                 = 2   # <
 	
-	END_OPENED    = 8  # <div ...></
-	END_AFTER_TAG = 9  # <div ...></div
-	END_CLOSED    = 10 # <div ...></div>, <div .../>
+	AFTER_TAG              = 4   # <div
+	AFTER_ATTRIBUTE_NAME   = 8   # <div attr
+	AFTER_ATTRIBUTE_EQUALS = 16  # <div attr=
+	AFTER_ATTRIBUTE_VALUE  = 32  # <div attr=val, <div
+	
+	CLOSED                 = 64  # <div ...>
+	CLOSED_VOID            = 128 # <div .../>
+	
+	END_OPENED    = 256  # <div ...></
+	END_AFTER_TAG = 512  # <div ...></div
+	END_CLOSED    = 1024 # <div ...></div>, <div .../>
+	
+	ILLEGAL = 2048
+	VALID_ATTRIBUTE_NAME_START = (4 + 8 + 32 + 2048)
 }
 
 class Token {
···
 			return [Token]::new( [TokenType]::EOF, '' )
 		}
 		
+		if ($this.State.HasFlag([ElementState]::ILLEGAL)) {
+			throw "Lexer found in illegal state $($this.State)"
+		}
+		
 		switch -Regex ($this.Char) {
 			'<' {
 				switch ($this.State) {
···
 			
 			'/' {
 				switch ($this.State) {
-					{$_ -in
-						[ElementState]::AFTER_TAG,
-						[ElementState]::AFTER_ATTRIBUTE_NAME,
-						[ElementState]::AFTER_ATTRIBUTE_VALUE
-					} {
+					{[ElementState]::VALID_ATTRIBUTE_NAME_START.HasFlag($_)} {
 						if ($this.PeekChar() -eq '>') {
 							$Token = [Token]::new( [TokenType]::VOID_ELEMENT_CLOSE, $this.Char + $this.PopChar() )
 							$this.State = [ElementState]::CLOSED_VOID
···
 			'>' {
 				# check for nested psx here!!!
 				switch ($this.State) {
-					{$_ -in
-						[ElementState]::AFTER_TAG,
-						[ElementState]::AFTER_ATTRIBUTE_NAME,
-						[ElementState]::AFTER_ATTRIBUTE_VALUE
-					} {
+					{[ElementState]::VALID_ATTRIBUTE_NAME_START.HasFlag($_)} {
 						$Token = [Token]::new( [TokenType]::CLOSE_ELEMENT, $this.Char )
 						$this.State = [ElementState]::CLOSED
 					}
···
 						
 						$this.State = [ElementState]::AFTER_TAG
 					}
-					{$_ -in
-						[ElementState]::AFTER_TAG,
-						[ElementState]::AFTER_ATTRIBUTE_NAME,
-						[ElementState]::AFTER_ATTRIBUTE_VALUE
-					} {
+					{[ElementState]::VALID_ATTRIBUTE_NAME_START.HasFlag($_)} {
 						$TokType = [TokenType]::ATTR_NAME
 						
 						$this.State = [ElementState]::AFTER_ATTRIBUTE_NAME
···
 			
 			default {
 				$Token = [Token]::new([TokenType]::ILLEGAL, $this.LexInput.Substring($this.Pos))
+				$this.State = [ElementState]::ILLEGAL
 			}
 		}