Parse multiple instructions

ldtext/Parser.fsy

@@ -3,9 +3,6 @@ open LDText.Ast
 open FSharp.Text.Lexing
 %}
 
-// start token
-%start instr
-
 // tokens, used by lexer
 %token <string> IDENTIFIER
 %token LEFT_PAREN
@@ -17,13 +14,20 @@ open FSharp.Text.Lexing
 %token QUESTION_MARK
 %token EOF
 
+// start token
+%start rung
+
 // return type of parser, marked by start token
-%type <Instr> instr
+%type <Instr list> rung
 
 %%
 
-//rung:
-//  | instr EOF { $1 }
+rung:
+  | steps SEMICOLON EOF { $1 }
+
+steps:
+  | { [] }
+  | instr steps { $1 :: $2 }
 
 instr:
   | IDENTIFIER LEFT_PAREN operands RIGHT_PAREN { { Op = $1; Args = $3 } }