🐐 NVLLVS and string concatenation

centvrion/ast_nodes.py

@@ -34,6 +34,7 @@ def rep_join(l):
 OP_STR = {
   "SYMBOL_PLUS": "+", "SYMBOL_MINUS": "-",
   "SYMBOL_TIMES": "*", "SYMBOL_DIVIDE": "/",
+  "SYMBOL_COLON": ":",
   "KEYWORD_EST": "EST", "KEYWORD_MINVS": "MINVS",
   "KEYWORD_PLVS": "PLVS", "KEYWORD_ET": "ET", "KEYWORD_AVT": "AVT",
 }
@@ -411,24 +412,32 @@ class BinOp(Node):
     lv, rv = left.value(), right.value()
     match self.op:
       case "SYMBOL_PLUS":
-        return vtable, ValInt(lv + rv)
+        if isinstance(lv, str) or isinstance(rv, str):
+          raise TypeError("Use : for string concatenation, not +")
+        if lv is None and rv is None:
+          return vtable, ValNul()
+        return vtable, ValInt((lv or 0) + (rv or 0))
+      case "SYMBOL_COLON":
+        lv = lv if lv is not None else ""
+        rv = rv if rv is not None else ""
+        return vtable, ValStr(lv + rv)
       case "SYMBOL_MINUS":
-        return vtable, ValInt(lv - rv)
+        return vtable, ValInt((lv or 0) - (rv or 0))
       case "SYMBOL_TIMES":
-        return vtable, ValInt(lv * rv)
+        return vtable, ValInt((lv or 0) * (rv or 0))
       case "SYMBOL_DIVIDE":
         # TODO: Fractio
-        return vtable, ValInt(lv // rv)
+        return vtable, ValInt((lv or 0) // (rv or 0))
       case "KEYWORD_MINVS":
-        return vtable, ValBool(lv < rv)
+        return vtable, ValBool((lv or 0) < (rv or 0))
       case "KEYWORD_PLVS":
-        return vtable, ValBool(lv > rv)
+        return vtable, ValBool((lv or 0) > (rv or 0))
       case "KEYWORD_EST":
         return vtable, ValBool(lv == rv)
       case "KEYWORD_ET":
-        return vtable, ValBool(bool(lv) and bool(rv))
+        return vtable, ValBool(bool(left) and bool(right))
       case "KEYWORD_AVT":
-        return vtable, ValBool(bool(lv) or bool(rv))
+        return vtable, ValBool(bool(left) or bool(right))
       case _:
         raise Exception(self.op)
 

centvrion/lexer.py

@@ -61,6 +61,7 @@ symbol_tokens = [
   ("SYMBOL_MINUS", r"\-"),
   ("SYMBOL_TIMES", r"\*"),
   ("SYMBOL_DIVIDE", r"\/"),
+  ("SYMBOL_COLON", r":"),
   ("SYMBOL_COMMA", r",")
 ]
 

centvrion/parser.py

@@ -13,7 +13,7 @@ class Parser():
         ('left', ["KEYWORD_AVT"]),
         ('left', ["KEYWORD_ET"]),
         ('left', ["KEYWORD_PLVS", "KEYWORD_MINVS", "KEYWORD_EST"]),
-        ('left', ["SYMBOL_PLUS", "SYMBOL_MINUS"]),
+        ('left', ["SYMBOL_COLON", "SYMBOL_PLUS", "SYMBOL_MINUS"]),
         ('left', ["SYMBOL_TIMES", "SYMBOL_DIVIDE"]),
         ('right', ["UMINUS"]),
         ('left', ["INDEX"]),
@@ -174,6 +174,7 @@ class Parser():
     def expression_nullus(_):
       return ast_nodes.Nullus()
 
+    @self.pg.production('expression : expression SYMBOL_COLON expression')
     @self.pg.production('expression : expression SYMBOL_MINUS expression')
     @self.pg.production('expression : expression SYMBOL_PLUS expression')
     @self.pg.production('expression : expression SYMBOL_TIMES expression')