✨

plthy_impl/ast_nodes.py

@@ -2,6 +2,13 @@ import random
 
 from rply.token import BaseBox
 
+
+BUILTIN_ARGS = {
+    "print": "*",
+    "input" : "*",
+    "random": 2
+}
+
 def rep_join(l):
     format_string = ',\n'.join(
         [repr(i) if not isinstance(i, str) else i for i in l]
@@ -11,7 +18,6 @@ def rep_join(l):
         format_string = f"\n  {format_string}\n"
 
     return format_string
-
 class Exp(BaseBox):
     def eval(self, vtable, ftable):
         return vtable, ftable, None
@@ -86,8 +92,7 @@ class ExpABinop(Exp):
         elif self.op == "<":
             return vtable, ftable, r1 < r2
         else:
-            print(f"E007: Unknown binop {self.op}")
-            exit()
+            raise Exception(f"Unknown binop {self.op}")
 
 class ExpList(Exp):
     def __init__(self, expressions: list[Exp]):
@@ -143,9 +148,15 @@ class Command(BaseBox):
         return f"command()"
 
 class Builtin(Command):
-    def __init__(self, builtin: str, args: list[Exp]):
-        self.builtin = builtin
+    def __init__(self, builtin, args: list[Exp]):
+        self.builtin = builtin.value
         self.args = args
+        self.position = builtin.source_pos.lineno
+        expected_args = BUILTIN_ARGS[self.builtin]
+
+        if not (expected_args == "*" or expected_args == len(self.args)):
+            print(f"E005: Wrong number of arguments for builtin '{self.builtin}' ({len(self.args)}) at line {self.position}")
+            exit()
 
     def __repr__(self) -> str:
         return f"builtin({self.builtin}, {self.args})"
@@ -174,10 +185,6 @@ class Builtin(Command):
             result = input()
             return vtable, ftable, result
         elif self.builtin == "random":
-            if not len(self.args) == 2:
-                print(f"E006: Wrong number of arguments for builtin '{self.builtin}' ({len(self.args)})")
-                exit()
-
             vtable, ftable, r1 = self.args[0].eval(vtable, ftable)
             vtable, ftable, r2 = self.args[1].eval(vtable, ftable)
 
@@ -185,7 +192,7 @@ class Builtin(Command):
 
             return vtable, ftable, r
         else:
-            raise Exception(f"E005: Unknown builtin {self.builtin}")
+            raise Exception(f"Unknown builtin {self.builtin}")
 
 class Do(BaseBox):
     def __init__(self, command: Command):
@@ -309,6 +316,22 @@ class StatementIf(Statement):
         else:
             return vtable, ftable, result
 
+class StatementBecause(Statement):
+    def __init__(self, statement: Statement, condition):
+        self.statement = statement
+        self.condition = condition
+
+    def __repr__(self) -> str:
+        return f"if({self.statement}, {self.condition})"
+
+    def eval(self, vtable, ftable):
+        vtable, ftable, result = self.condition.eval(vtable, ftable)
+        if result:
+            return self.statement.eval(vtable, ftable)
+        else:
+            print("C001: Because assertion incorrect")
+            exit()
+
 class StatementUntil(Statement):
     def __init__(self, statement: Statement, condition):
         self.statement = statement

plthy_impl/lexer.py

@@ -9,13 +9,14 @@ KEYWORD_TOKENS = [("KEYWORD_"+i.upper(), i) for i in [
     "maybe",
     "do",
     "if",
-#    "because",
+    "because",
     "until",
     "define",
     "as",
     "variable",
     "return",
-    "argument"
+    "argument",
+    "set"
 ]]
 
 BUILTIN_TOKENS = [("BUILTIN", i) for i in [
@@ -50,7 +51,7 @@ SYMBOL_TOKENS = [
     ("SYMBOL_LT", r"\<"),
     ("SYMBOL_GT", r"\>"),
     ("SYMBOL_EQUALS", r"\="),
-    ("SYMBOL_DOLLAR", r"\$")
+#    ("SYMBOL_DOLLAR", r"\$")
 ]
 
 ALL_TOKENS = (

plthy_impl/parser.py

@@ -9,9 +9,9 @@ class Parser():
             [i[0] for i in ALL_TOKENS],
             precedence=[
                 ('left', ["KEYWORD_MAYBE", "KEYWORD_RETURN"]),
-                ('left', ["KEYWORD_IF", "KEYWORD_UNTIL", "KEYWORD_DEFINE", "KEYWORD_AS"]),
-                ('left', ["KEYWORD_DO", "BUILTIN"]),
-                ('left', ["SYMBOL_EQUALS", "SYMBOL_SET"]),
+                ('left', ["KEYWORD_IF", "KEYWORD_BECAUSE", "KEYWORD_UNTIL", "KEYWORD_DEFINE", "KEYWORD_AS"]),
+                ('left', ["KEYWORD_DO", "BUILTIN", "SYMBOL_SET"]),
+                ('left', ["SYMBOL_EQUALS"]),
                 ('left', ["SYMBOL_PLUS", "SYMBOL_MINUS"]),
                 ('left', ["SYMBOL_TIMES", "SYMBOL_DIVIDE", "SYMBOL_LT","SYMBOL_GT"])
             ]
@@ -33,7 +33,7 @@ class Parser():
             return [tokens[0]] + tokens[2]
 
         ## statement ##
-        @self.pg.production('statement : SYMBOL_DOLLAR expression SYMBOL_SET ID', precedence="SYMBOL_SET")
+        @self.pg.production('statement : KEYWORD_SET expression SYMBOL_SET ID', precedence="SYMBOL_SET")
         def statement_set(tokens):
             return ast_nodes.StatementSet(tokens[1], tokens[3].value)
 
@@ -49,6 +49,10 @@ class Parser():
         def statement_if(tokens):
             return ast_nodes.StatementIf(tokens[0], tokens[2])
 
+        @self.pg.production('statement : statement KEYWORD_BECAUSE expression')
+        def statement_because(tokens):
+            return ast_nodes.StatementBecause(tokens[0], tokens[2])
+
         @self.pg.production('statement : KEYWORD_UNTIL expression statement')
         def statement_until(tokens):
             return ast_nodes.StatementUntil(tokens[2],tokens[1])
@@ -68,7 +72,7 @@ class Parser():
         ## command ##
         @self.pg.production('command : BUILTIN SYMBOL_LT expressions SYMBOL_GT')
         def command_builtin(tokens):
-            return ast_nodes.Builtin(tokens[0].value, tokens[2])
+            return ast_nodes.Builtin(tokens[0], tokens[2])
 
         @self.pg.production('command : SYMBOL_QUOTE ID SYMBOL_QUOTE SYMBOL_LT expressions SYMBOL_GT')
         def command_call(tokens):
@@ -89,7 +93,7 @@ class Parser():
             return ast_nodes.ExpInt(int(tokens[0].value))
 
         @self.pg.production('expression : DATA_FLOAT')
-        def exp_int(tokens):
+        def exp_float(tokens):
             return ast_nodes.ExpInt(float(tokens[0].value))
 
         @self.pg.production('expression : DATA_STRING')