lib/standard/text: Added parsing method for all integers

Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>

diff --git a/lib/standard/text/abstract_text.nit b/lib/standard/text/abstract_text.nit
index cf0d1dc..22f25f2 100644 (file)
--- a/lib/standard/text/abstract_text.nit
+++ b/lib/standard/text/abstract_text.nit
@@ -292,6 +292,37 @@ abstract class Text
                return ""
        end
 
+       # Removes the numeric extension if present
+       #
+       #     intrude import standard::text::abstract_text
+       #     assert "0xFEFFu8".strip_numext  == "0xFEFF"
+       #     assert "0b01001u8".strip_numext == "0b01001"
+       #     assert "0o872u8".strip_numext   == "0o872"
+       #     assert "98".strip_numext        == "98"
+       private fun strip_numext: Text do
+               var ext = get_numext
+               if ext != "" then return substring(0, length - ext.length)
+               return self
+       end
+
+       # Gets the numeric extension (i/u 8/16/32) in `self` is present
+       # Returns "" otherwise
+       #
+       #     intrude import standard::text::abstract_text
+       #     assert "0xFEFFu8".get_numext  == "u8"
+       #     assert "0b01001u8".get_numext == "u8"
+       #     assert "0o872u8".get_numext   == "u8"
+       #     assert "98".get_numext        == ""
+       private fun get_numext: Text do
+               var len = self.length
+               var max = if self.length < 3 then self.length else 3
+               for i in [1 .. max] do
+                       var c = self[len - i]
+                       if c == 'i' or c == 'u' then return substring_from(len - i)
+               end
+               return ""
+       end
+
        # Returns `self` as the corresponding integer
        #
        #     assert "123".to_i        == 123
@@ -330,6 +361,44 @@ abstract class Text
                return if neg then -val else val
        end
 
+       # Is `self` a valid integer ?
+       #
+       #     assert "0xFE46u8".is_num
+       #     assert "0b0100".is_num
+       #     assert "0o645".is_num
+       #     assert "897u8".is_num
+       fun is_num: Bool do
+               var prefix = get_numhead
+               var s = strip_numhead.strip_numext.remove_all('_')
+               if prefix != "" then
+                       var c = prefix[1]
+                       if c == 'x' or c == 'X' then return s.is_hex
+                       if c == 'o' or c == 'O' then return s.is_oct
+                       if c == 'b' or c == 'B' then return s.is_bin
+               end
+               return s.is_dec
+       end
+
+       # Is `self` is a properly formatted integer, returns the corresponding value
+       #
+       #     assert "0xFEu8".to_num  == 254u8
+       #     assert "0b10_10".to_num != 10u8
+       fun to_num: nullable Numeric do
+               if not is_num then return null
+               var s = remove_all('_')
+               var ext = s.get_numext
+               var trunk = s.strip_numext
+               if trunk.strip_numhead == "" then return null
+               var trval = trunk.to_i
+               if ext == "u8" then
+                       return trval.to_b
+               else if ext == "" then
+                       return trval
+               else
+                       return null
+               end
+       end
+
        # If `self` contains a float, return the corresponding float
        #
        #     assert "123".to_f        == 123.0