Improve class uri handling

This commit improves handling full class uris in three ways:
 - It preserves the `$base` field in a `_base` global variable to allow
   using it in the generated Python parser
 - It relies on the `_base` variable to distinguish between base classes
   and namespaced extensions while saving a document
 - It removes the `class_uri` field and retrieves the full class uri
   directly from the `rvocab` data structure

Author: GlassOfWhiskey

schema_salad/codegen.py

@@ -84,7 +84,7 @@ def codegen(
             gen.parse(j)
             return
         gen = PythonCodeGen(
-            dest, copyright=copyright, parser_info=info, salad_version=salad_version
+            base, dest, copyright=copyright, parser_info=info, salad_version=salad_version
         )
 
     elif lang == "java":

schema_salad/metaschema.py

@@ -7267,6 +7267,7 @@ def save(
     )
 
 
+_base = "https://w3id.org/cwl/salad#"
 _vocab = {
     "Any": "https://w3id.org/cwl/salad#Any",
     "ArraySchema": "https://w3id.org/cwl/salad#ArraySchema",

schema_salad/python_codegen.py

@@ -70,12 +70,14 @@ class PythonCodeGen(CodeGenBase):
 
     def __init__(
         self,
+        base: str,
         out: IO[str],
         copyright: Optional[str],
         parser_info: str,
         salad_version: str,
     ) -> None:
         super().__init__()
+        self.base_uri = base
         self.out = out
         self.current_class_is_abstract = False
         self.serializer = StringIO()
@@ -143,7 +145,6 @@ def begin_class(
         idfield: str,
         optional_fields: set[str],
     ) -> None:
-        class_uri = classname
         classname = self.safe_name(classname)
 
         if extends:
@@ -166,12 +167,7 @@ def begin_class(
 
         idfield_safe_name = self.safe_name(idfield) if idfield != "" else None
         if idfield_safe_name is not None:
-            self.out.write(f"    {idfield_safe_name}: str\n")
-            if "class" not in field_names:
-                self.out.write("\n")
-
-        if "class" in field_names:
-            self.out.write(f'    class_uri = "{class_uri}"\n\n')
+            self.out.write(f"    {idfield_safe_name}: str\n\n")
 
         required_field_names = [f for f in field_names if f not in optional_fields]
         optional_field_names = [f for f in field_names if f in optional_fields]
@@ -602,7 +598,8 @@ def declare_field(
 
         if shortname(name) == "class":
             self.out.write(
-                """{spc}            if {safename} != cls.__name__ and {safename} != cls.class_uri:
+                """
+{spc}            if {safename} not in (cls.__name__, loadingOptions.vocab.get(cls.__name__)):
 {spc}               raise ValidationException(f"tried `{{cls.__name__}}` but")
 {spc}        except ValidationException as e:
 {spc}               raise e
@@ -667,9 +664,10 @@ def declare_field(
                 fmt(
                     """
 if self.{safename} is not None:
-    if p := self.loadingOptions.rvocab.get(self.class_uri[:-len(self.{safename})]):
+    uri = self.loadingOptions.vocab[self.{safename}]
+    if p := self.loadingOptions.rvocab.get(uri[:-len(self.{safename})]):
         uri = f"{{p}}:{{self.{safename}}}"
-    else:
+    elif uri.startswith(_base):
         uri = self.{safename}
     u = save_relative_uri(uri, {baseurl}, {scoped_id}, {ref_scope}, relative_uris)
     r["{fieldname}"] = u
@@ -769,6 +767,8 @@ def secondaryfilesdsl_loader(self, inner: TypeDef) -> TypeDef:
     def epilogue(self, root_loader: TypeDef) -> None:
         """Trigger to generate the epilouge code."""
 
+        self.out.write(f'_base = "{self.base_uri}"\n')
+
         self.out.write("_vocab = {\n")
         for k in sorted(self.vocab.keys()):
             self.out.write(f'    "{k}": "{self.vocab[k]}",\n')  # noqa: B907