Re: XMLAda & unicode symbols

["196...@googlemail.com" <1963bib@googlemail.com>]

On Saturday, 19 June 2021 at 22:24:47 UTC+1, Simon Wright wrote:
> "196...@googlemail.com" <196...@googlemail.com> writes: 
> 
> > I'm creating SVG files with XMLAda and I need to have a degree symbol 
> > within some text. 
> > 
> > I have: 
> > procedure Add_Min_Max (Min_Max_Str : String; X_Pos : String; Y_Pos : String) is 
> > Text_Node : DOM.Core.Element; 
> > Text : DOM.Core.Text; 
> > begin 
> > Text_Node := DOM.Core.Documents.Create_Element (LDocument, "text"); 
> > DOM.Core.Elements.Set_Attribute (Text_Node, "x", X_Pos); 
> > DOM.Core.Elements.Set_Attribute (Text_Node, "y", Y_Pos); 
> > DOM.Core.Elements.Set_Attribute (Text_Node, "class", "def-maroon"); 
> > DOM.Core.Elements.Set_Attribute (Text_Node, "text-anchor", "left"); 
> > Text_Node := DOM.Core.Nodes.Append_Child (Root_Node, Text_Node); 
> > Text := DOM.Core.Documents.Create_Text_Node (LDocument, Min_Max_Str); 
> > Text := DOM.Core.Nodes.Append_Child (Text_Node, Text); 
> > end Add_Min_Max; 
> > 
> > and I just pass a string in. The degree symbol is unicode 00B0 and you 
> > would then normally have it as &#00B0, except if I do, then XMLAda 
> > changes that initial '&' to '&amp' and so what is then coded is 
> > '&amp#00B0' and it fails to display properly. 
> > 
> > Nor can I apply Unicode.Names.Latin_1_Supplement.Degree_Sign to the 
> > string, since, well, strict typing... 
> > 
> > To me it seems like XMLAda is being far too eager and is not willing 
> > to just publish what I enter. 
> > 
> > I raised a call on the github repository, but it was closed saying 
> > basically use the unicode name, which fails.
> Set_Attribute takes a Dom_String, which is a subtype of 
> Unicode.CES.Byte_Sequence, which is a subtype of String. The question 
> is, what encoding? I suspect it's utf-8, so we need to encode 
> Ada.Characters.Latin_1.Degree_Sign in utf-8, & this code using XML/Ada 
> support seems to do the trick: 
> 
> with Ada.Characters.Latin_1; 
> with Ada.Text_IO; 
> with Unicode.CES; 
> with Unicode.Encodings; 
> procedure Conversion is 
> Fifty_Degrees_Latin1 : constant String 
> := "50" & Ada.Characters.Latin_1.Degree_Sign; 
> Fifty_Degrees_UTF8 : constant Unicode.CES.Byte_Sequence 
> := "50" 
> & Unicode.Encodings.Convert 
> ((1 => Ada.Characters.Latin_1.Degree_Sign), 
> From => Unicode.Encodings.Get_By_Name ("iso-8859-15"), 
> To => Unicode.Encodings.Get_By_Name ("utf-8")); 
> begin 
> Ada.Text_IO.Put_Line (Fifty_Degrees_Latin1); 
> Ada.Text_IO.Put_Line (Fifty_Degrees_UTF8); 
> end Conversion; 
> 
> (note that Convert's From and To parameters are the default). On this 
> Mac (Terminal displays utf-8 text) the first line is garbage, the second 
> fine. 
> 
> I'm So Wildly Impressed (maybe "cast down" would be more accurate) by 
> all that subtyping in our wondrously safe language. 
> 
> I also agree with you that suggesting you use a Unicode_Char 
> (Wide_Wide_Character) without saying *how* is less helpful than it could 
> be.

Asking for the degree sign, was probably a slight mistake. There is Degree_Celsius and also Degree_Fahrenheit for those who have not yet embraced metric. These are the "correct" symbols.

Both of these exist in Unicode.Names.Letterlike_Symbols, and probably elsewhere,but trying to shoehorn these in seems impossible.

I just wish XMLAda could just accept whatever we throw at it, and if we need to convert it, then let us do so outside of it.

Using Text_IO is fine, but not where XMLAda is concerned.


B