update grammar and test file

src/skill.pest

@@ -16,7 +16,7 @@ cstyle_list = @{ token ~ lisp_list}
 
 list = { (cstyle_list | lisp_list | lazy_list) }
 
-assign = {token ~ "=" ~ (inline_expr | list | token)}
+assign = {token ~ "=" ~ (inline_expr | list | token | literal)}
 inline_operand = _{(list | token | literal)}
 inline_operator = {("-" | "+" | "/" | "*")}
 inline_expr = {inline_operand ~ (inline_operator ~ inline_operand)+}
@@ -25,4 +25,4 @@ get_operator = {("->" | "~>")}
 get = {token ~ get_operator ~ (list | token)}
 
 expr = _{(get | assign | list | token | literal)}
-skill = { SOI ~ expr* ~ EOI }
+skill = { SOI ~ expr* ~ EOI }

test/data/test.il

@@ -19,4 +19,4 @@ obj->op()
 (let (a (b 3))
     expr1
     expr2
-)
+)