Parse single instruction in neutral text

ldtext/Parser.fsy

@@ -1,10 +1,10 @@
 %{
 open LDText.Ast
-// helper functions
+open FSharp.Text.Lexing
 %}
 
 // start token
-%start start
+%start instr
 
 // tokens, used by lexer
 %token <string> IDENTIFIER
@@ -18,19 +18,20 @@ open LDText.Ast
 %token EOF
 
 // return type of parser, marked by start token
-%type <Rung option> rung
+%type <Instr> instr
 
 %%
 
-start:
-  | instr EOF { $1 }
+//rung:
+//  | instr EOF { $1 }
 
 instr:
-  | IDENTIFIER LEFT_PAREN operands RIGHT_PAREN { StepInstr { Op = $1; Args = [ $3 ] } }
+  | IDENTIFIER LEFT_PAREN operands RIGHT_PAREN { { Op = $1; Args = $3 } }
 
 operands:
-  | { }
-  | operand operands { $1; $2 }
+  | { [] }
+  | operand COMMA operands { $1 :: $3 }
+  | operand { [ $1 ] }
 
 operand:
   | IDENTIFIER { OperandTag $1 }