Fixed #101 : Implement PLURIAL

Fixed #103 : Implement PlurialNodeParser
Fixed #104 : Implement dynamic concept
Fixed #107 : PrepareEvalxxxEvaluator: context hints are lost on a second evaluation

src/parsers/SequenceNodeParser.py

@@ -4,6 +4,7 @@ from core import builtin_helpers
 from core.builtin_concepts import BuiltinConcepts
 from core.builtin_helpers import update_concepts_hints
 from core.concept import DEFINITION_TYPE_BNF, Concept
+from core.global_symbols import NotFound
 from core.sheerka.services.SheerkaExecute import ParserInput
 from core.tokenizer import Tokenizer, TokenKind
 from core.utils import strip_tokens, make_unique
@@ -245,13 +246,7 @@ class SequenceNodeParser(BaseNodeParser):
         if token.type == TokenKind.WHITESPACE:
             return None
 
-        def as_list(a):
-            if a is None:
-                return None
-
-            return a if isinstance(a, list) else [a]
-
-        concepts_by_name = as_list(self.sheerka.fast_resolve(token))
+        concepts_by_name = self.as_list(self.sheerka.fast_resolve(token))
         concepts_by_first_keyword = new_instances(self.sheerka.get_concepts_by_first_token(token, self._is_eligible))
 
         if concepts_by_name is None:
@@ -299,6 +294,10 @@ class SequenceNodeParser(BaseNodeParser):
 
                 concepts = self.get_concepts(token, self._is_eligible)
                 # self.context.log(f"concepts found for {token=}: {concepts}", who=self.name)
+
+                if not concepts:
+                    concepts = self.get_plural(token)
+
                 if not concepts:
                     for concept_parser in concept_parser_helpers:
                         concept_parser.eat_unrecognized(token, pos)
@@ -454,3 +453,30 @@ class SequenceNodeParser(BaseNodeParser):
                 self.name,
                 False,
                 context.sheerka.new(BuiltinConcepts.NOT_FOR_ME, body=parser_input.as_text()))
+
+    def get_plural(self, token):
+        if not token.type == TokenKind.IDENTIFIER:
+            return None
+
+        if not token.value.endswith("s"):
+            return None
+
+        concept_name = token.value[:-1]  # remove the trailing 's'
+        concepts = self.as_list(self.sheerka.fast_resolve(concept_name))
+
+        if concepts is None:
+            return None
+
+        eligible = [c for c in concepts if self.sheerka.known_plural(c) == NotFound]
+        if not eligible:
+            return None
+
+        return [self.sheerka.new_dynamic(c, BuiltinConcepts.PLURAL, name=token.value, props={BuiltinConcepts.PLURAL: c})
+                for c in concepts]
+
+    @staticmethod
+    def as_list(obj):
+        if obj is None:
+            return None
+
+        return obj if isinstance(obj, list) else [obj]