2 files changed, 60 insertions, 40 deletions
diff --git a/nandgame/assembler/parser.py b/nandgame/assembler/parser.py
index 9e4bf45..a140eea 100755
--- a/nandgame/assembler/parser.py
+++ b/nandgame/assembler/parser.py
@@ -8,14 +8,9 @@ from ply.lex import LexToken
 # Get the token map from the lexer.  This is required.
 from lexer import tokens
 
-# Error rule for syntax errors
-
+import parsetypes as pt
 
-def p_error(p: LexToken):
-    if p:
-        print(f"Unexpected {repr(p.value)} on line {p.lineno}")
-    else:
-        print("Unexpected end of file.")
+# Error rule for syntax errors
 
 
 def p_program(p):
@@ -30,7 +25,7 @@ def p_empty(p):
     pass
 
 
-def p_inss(p):
+def p_instructions(p):
     """instruction_list : instruction_list line
                         | line
     """
@@ -38,15 +33,11 @@ def p_inss(p):
         p[0] = [p[1]]
     else:
         p[0] = p[1] + [p[2]]
-
-    # print(f"INSes: {len(p)}")
-    # print(f"    {p[1]}")
-    # if len(p) > 2:
-    #     print(f"    {p[2]}")
     pass
 
 
-def p_inss2(p):
+# try right-recursive?
+def p_instructions2(p):
     """instruction_list2 : line instruction_list2
                          | line
     """
@@ -73,11 +64,11 @@ def p_line(p):
 
 
 def p_instruction(p):
-    """instruction : noarg
-                   | onearg
-                   | twoarg
+    """instruction : no_args
+                   | two_arg
+                   | three_arg
                    | jumpdest
-                   | invalid_arg
+                   | one_arg_invalid
     """
     print(f"Item: {p[1]}")
     p[0] = p[1]
@@ -85,46 +76,57 @@ def p_instruction(p):
 
 
 def p_jumpdest(p):
-    """jumpdest : SYMBOL COLON"""
+    """jumpdest : symbol COLON"""
     p[0] = (p[1],)
 
 
-def p_twoarg(p):
-    """twoarg : op REG COMMA argument COMMA argument"""
-    p[0] = (*p[1], p[2], p[4], p[6])
+def p_no_arg(p):
+    """no_args : opcode"""
+    p[0] = (*p[1], None, None, None)
     pass
 
 
-def p_argument(p):
-    """argument : number
-                | REG
-                | SYMBOL
-    """
+def p_onearg_invalid(p):
+    """one_arg_invalid : opcode argument"""
+    print(f"Invalid number of arguments: {p[1:]}")
+    sys.exit(1)
     pass
 
 
-def p_onearg(p):
-    """onearg : op REG COMMA argument"""
+def p_two_arg(p):
+    """two_arg : opcode register COMMA argument"""
     p[0] = (*p[1], p[2], p[4], None)
     pass
 
 
-def p_noarg(p):
-    """noarg : op"""
-    p[0] = (*p[1], None, None, None)
+def p_three_arg(p):
+    """three_arg : opcode register COMMA argument COMMA argument"""
+    p[0] = (*p[1], p[2], p[4], p[6])
     pass
 
 
-def p_invalid_arg(p):
-    """invalid_arg : op argument"""
-    print(f"Invalid opcode, destination missing: {p[1:]}")
-    sys.exit(1)
-    pass
+# checks which combinations are allowed is done one level up
+def p_argument(p):
+    """argument : number
+                | register
+                | symbol
+    """
+    p[0] = p[1]
+
+
+def p_symbol(p):
+    """symbol : SYMBOL"""
+    p[0] = pt.Symbol(p[1])
+
 
+def p_register(p):
+    """register : REG"""
+    p[0] = pt.Register(p[1])
 
-def p_op(p):
-    """op : OP DOT JUMP
-          | OP
+
+def p_opcode(p):
+    """opcode : OP DOT JUMP
+              | OP
     """
     if len(p) == 2:
         p[0] = (p[1], None)
@@ -139,4 +141,11 @@ def p_number(p):
     p[0] = p[1]
 
 
+def p_error(p: LexToken):
+    if p:
+        print(f"Unexpected {repr(p.value)} on line {p.lineno}")
+    else:
+        print("Unexpected end of file.")
+
+
 parser = yacc.yacc()
diff --git a/nandgame/assembler/parsetypes.py b/nandgame/assembler/parsetypes.py
new file mode 100644
index 0000000..4769e02
--- /dev/null
+++ b/nandgame/assembler/parsetypes.py
@@ -0,0 +1,11 @@
+from dataclasses import dataclass
+
+@dataclass
+class Symbol:
+    """Define a symbol"""
+    name: str
+
+@dataclass
+class Register:
+    """Define a source or dest register"""
+    name: str