feat: Started adding references

src/glxml.gleam

@@ -39,16 +39,16 @@ pub type Element {
 
 pub fn main() {
   parse_document(
-    "<?xml version=\"1.1\" encoding='UTF-8'?>\r\n   <!-- hello-world -->   \n<a attr='ha&#x20;ha' battr='baba' ref='&ref;'/>",
+    "<?xml version=\"1.1\" encoding='UTF-8'?>\r\n   <!-- hello-world -->   \n<a attr='ha&#x20;&#38;#38;ha' battr='baba' ref='&amp;'/>",
   )
   |> echo
 }
 
 pub fn default_entities() -> dict.Dict(String, Entity) {
   dict.from_list([
-    #("lt", InternalEntity("&#38;#60;")),
+    #("lt", InternalEntity("&#60;")),
-    #("gt", InternalEntity("#62;")),
+    #("gt", InternalEntity("&#62;")),
-    #("amp", InternalEntity("&#38;#38;")),
+    #("amp", InternalEntity("&#38;")),
     #("apos", InternalEntity("&#39;")),
     #("quot", InternalEntity("&#34;")),
   ])
@@ -60,7 +60,7 @@ fn parse_document(doc: String) -> Result(Document, Nil) {
   use #(element, doc) <- result.try(parse_element(doc, doctype))
   let doc = parse_misc(doc)
 
-  case doc |> echo {
+  case doc {
     "" -> Ok(Document(decl, doctype, Some(element)))
     _ -> Error(Nil)
   }
@@ -77,7 +77,7 @@ fn parse_empty_elem(
   doc: String,
   doctype: Option(DocType),
 ) -> Result(#(Element, String), Nil) {
-  case doc |> echo {
+  case doc {
     "<" <> tail -> {
       use #(name, doc) <- result.try(parse_name(tail))
       use #(attrs, doc) <- result.try(parse_attributes(doc, doctype, []))
@@ -184,19 +184,19 @@ fn parse_reference(
             ";" <> tail -> {
               use value <- result.try(int.base_parse(digits, 16))
               use codepoint <- result.try(string.utf_codepoint(value))
-              Ok(#("", string.from_utf_codepoints([codepoint]) <> tail))
+              Ok(#(string.from_utf_codepoints([codepoint]), tail))
             }
             _ -> Error(Nil)
           }
         }
         _ -> {
           use #(digits, doc) <- result.try(parse_multiple(tail, parse_digit))
-
           case doc {
             ";" <> tail -> {
               use value <- result.try(int.base_parse(digits, 10))
               use codepoint <- result.try(string.utf_codepoint(value))
-              Ok(#("", string.from_utf_codepoints([codepoint]) <> tail))
+
+              Ok(#(string.from_utf_codepoints([codepoint]), tail))
             }
             _ -> Error(Nil)
           }
@@ -207,7 +207,10 @@ fn parse_reference(
       use #(name, doc) <- result.try(parse_name(tail))
 
       case doc {
-        ";" <> tail -> Ok(#(char <> name <> ";", tail))
+        ";" <> tail -> {
+          use value <- result.try(process_reference(name, doctype))
+          Ok(#("", value <> tail))
+        }
         _ -> Error(Nil)
       }
     }
@@ -215,6 +218,36 @@ fn parse_reference(
   }
 }
 
+fn process_reference(
+  ref: String,
+  doctype: Option(DocType),
+) -> Result(String, Nil) {
+  case doctype {
+    Some(DocType(_, entities)) -> {
+      get_reference(entities, ref)
+    }
+    None -> {
+      get_reference(default_entities(), ref)
+    }
+  }
+}
+
+fn get_reference(
+  entities: dict.Dict(String, Entity),
+  ref: String,
+) -> Result(String, Nil) {
+  case dict.get(entities, ref) {
+    Ok(InternalEntity(val)) -> Ok(val)
+    Ok(PublicExternalEntity(_, _)) | Ok(SystemExternalEntity(_)) -> Error(Nil)
+    Error(_) -> {
+      case entities == default_entities() {
+        True -> Error(Nil)
+        False -> get_reference(default_entities(), ref)
+      }
+    }
+  }
+}
+
 fn parse_name(doc: String) -> Result(#(String, String), Nil) {
   case parse_name_start_char(doc) {
     Ok(#(char, tail)) -> {