Added keyword c:xxx: to express that we want the concept, not its body

core/tokenizer.py

@@ -8,6 +8,7 @@ class TokenKind(Enum):
     NEWLINE = "newline"
     KEYWORD = "keyword"
     IDENTIFIER = "identifier"
+    CONCEPT = "concept"
     STRING = "string"
     NUMBER = "number"
     TRUE = "true"
@@ -210,6 +211,11 @@ class Tokenizer:
                 self.i += len(newline)
                 self.column = 1
                 self.line += 1
+            elif c == "c" and self.i + 1 < self.text_len and self.text[self.i + 1] == ":":
+                concept_name = self.eat_concept_name(self.i + 2, self.line, self.column)
+                yield Token(TokenKind.CONCEPT, concept_name, self.i, self.line, self.column)
+                self.i += len(concept_name) + 3
+                self.column += len(concept_name) + 3
             elif c.isalpha() or c == "_":
                 identifier = self.eat_identifier(self.i)
                 token_type = TokenKind.KEYWORD if identifier in self.KEYWORDS else TokenKind.IDENTIFIER
@@ -233,6 +239,32 @@ class Tokenizer:
 
         yield Token(TokenKind.EOF, "", self.i, self.line, self.column)
 
+    def eat_concept_name(self, start, line, column):
+        result = ""
+        i = start
+        end_colon_found = False
+
+        while i < self.text_len:
+            c = self.text[i]
+
+            if c == "\n":
+                raise LexerError(f"New line is forbidden in concept name", result, i, line, column + 2 + len(result))
+
+            if c == ":":
+                end_colon_found = True
+                break
+
+            result += c
+            i += 1
+
+        if not end_colon_found:
+            raise LexerError(f"Missing ending colon", result, i, line, column + 2 + len(result))
+
+        if result == "":
+            raise LexerError(f"Context name not found", result, start, line, column + 2 + len(result))
+
+        return result
+
     def eat_whitespace(self, start):
         result = self.text[start]
         i = start + 1