compiler: Added prefix and suffix support for `Char`

[nit.git] / src / literal.nit

diff --git a/src/literal.nit b/src/literal.nit
index b183301..72df12b 100644 (file)
--- a/src/literal.nit
+++ b/src/literal.nit
@@ -95,17 +95,66 @@ redef class AFloatExpr
        end
 end
 
+# 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 return text.substring_from(text.index_of(delimiter_start)).substring(0, text.last_index_of(delimiter_end) + 1)
+end
+
 redef class ACharExpr
+       super AAugmentedLiteral
        # The value of the literal char once computed.
-       var value: nullable Char
+       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
+
        redef fun accept_literal(v)
        do
-               var txt = self.n_char.text.unescape_nit
+               if not is_valid_augmentation then
+                       v.toolcontext.error(hot_location, "Syntax Error: invalid prefix/suffix combination {prefix}/{suffix}")
+                       return
+               end
+               var txt = content.unescape_nit
                if txt.length != 3 then
                        v.toolcontext.error(self.hot_location, "Syntax Error: invalid character literal `{txt}`.")
                        return
                end
                self.value = txt.chars[1]
+               if is_ascii and txt.chars[1].code_point > 127 then v.toolcontext.error(self.hot_location, "Syntax Error: usage of byte prefix on multibyte character.")
        end
 end