+# Any kind of literal which supports a prefix or a suffix
+class AAugmentedLiteral
+ # Returns the text of the token
+ private fun text: String is abstract
+
+ # Is the combination of prefixes and suffixes in `self` valid ?
+ fun is_valid_augmentation: Bool is abstract
+
+ private fun delimiter_start: Char is abstract
+
+ private fun delimiter_end: Char is abstract
+
+ # Prefix for the entity, "" if no prefix is found
+ protected var prefix: String is lazy do return text.substring(0, text.index_of(delimiter_start))
+
+ # Suffix for the entity, "" if no prefix is found
+ protected var suffix: String is lazy do return text.substring_from(text.last_index_of(delimiter_end) + 1)
+
+ # Content of the entity, without prefix nor suffix
+ protected var content: String is lazy do
+ var npr = text.substring_from(prefix.length)
+ return npr.substring(0, npr.length - suffix.length)
+ end
+end
+
+redef class ACharExpr
+ super AAugmentedLiteral
+ # The value of the literal char once computed.
+ var value: nullable Char = null
+
+ redef fun delimiter_start do return '\''
+
+ redef fun delimiter_end do return '\''
+
+ # Is the expression returning an ASCII byte value ?
+ fun is_ascii: Bool do return prefix == "b"
+
+ # Is the expression returning a Code Point ?
+ fun is_code_point: Bool do return prefix == "u"
+
+ redef fun text do return n_char.text
+
+ redef fun is_valid_augmentation do
+ if suffix != "" then return false
+ if is_ascii then return true
+ if is_code_point then return true
+ if prefix != "" then return false
+ return true
+ end
+