From a7a070371bcc10d0dbf94e503650856ac37ed81d Mon Sep 17 00:00:00 2001
From: Felix Perktold <Felix.Perktold@student.uibk.ac.at>
Date: Mon, 22 Dec 2025 00:14:15 +0100
Subject: add reading from files, add quote shorthand (')

---
 lisp.y | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

(limited to 'lisp.y')

diff --git a/lisp.y b/lisp.y
index ffb9bf9..5a39640 100644
--- a/lisp.y
+++ b/lisp.y
@@ -15,40 +15,36 @@ int yyerror(const char *s);
 }
 %token <dval> NUMBER
 %token <strval> STRING SYMBOL
-%token <ival> LPAREN RPAREN DOT
-%token <ival> PLUS MINUS MULT DIV
+%token <ival> LPAREN RPAREN DOT QUOTE
 
-%type <val> sexpr atom list list_items
+%type <val> expr atom list list_items
 
-%start sexprs
+%start exprs
 
 %%
-sexprs: sexpr
+exprs: expr
       {
         value *v = eval(global_env, $1);
         printf(";> ");
         println_value(v);
       }
-      | sexprs sexpr
+      | exprs expr
       {
         value *v = eval(global_env, $2);
         printf(";> ");
         println_value(v);
       };
 
-sexpr:  atom
-     |  list
-     |  LPAREN sexpr DOT sexpr RPAREN
-     {
-       $$ = cons($2, $4);
-     };
+expr:  atom
+     | list
+     | LPAREN expr DOT expr RPAREN { $$ = cons($2, $4); }
+     | QUOTE expr { $$ = cons(make_symbol("quote"), cons($2, make_nil())); };
 
-list: LPAREN list_items RPAREN
-    { $$ = $2; };
+list: LPAREN list_items RPAREN { $$ = $2; };
 
 list_items: /* empty list */ { $$ = make_nil(); }
-          | sexpr list_items { $$ = cons($1, $2); }
-          | sexpr DOT sexpr { $$ = cons($1, $3); };
+          | expr list_items { $$ = cons($1, $2); }
+          | expr DOT expr { $$ = cons($1, $3); };
 
 atom:   NUMBER
     {
-- 
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