---input---
"a" "b" f"{x}" "{c}" f"str<{y:^4}>" "d" "e"

---tokens---
'"'           Literal.String.Double
'a'           Literal.String.Double
'"'           Literal.String.Double
' '           Text
'"'           Literal.String.Double
'b'           Literal.String.Double
'"'           Literal.String.Double
' '           Text
'f'           Literal.String.Affix
'"'           Literal.String.Double
'{'           Literal.String.Interpol
'x'           Name
'}'           Literal.String.Interpol
'"'           Literal.String.Double
' '           Text
'"'           Literal.String.Double
'{c}'         Literal.String.Interpol
'"'           Literal.String.Double
' '           Text
'f'           Literal.String.Affix
'"'           Literal.String.Double
'str<'        Literal.String.Double
'{'           Literal.String.Interpol
'y'           Name
':'           Literal.String.Interpol
'^4'          Literal.String.Double
'}'           Literal.String.Interpol
'>'           Literal.String.Double
'"'           Literal.String.Double
' '           Text
'"'           Literal.String.Double
'd'           Literal.String.Double
'"'           Literal.String.Double
' '           Text
'"'           Literal.String.Double
'e'           Literal.String.Double
'"'           Literal.String.Double
'\n'          Text.Whitespace