1 files changed, 3 insertions, 2 deletions

diff --git a/grammar.bnf b/grammar.bnf
index 7c18f8f..9ddaffc 100644
--- a/grammar.bnf
+++ b/grammar.bnf
@@ -4,7 +4,7 @@ program ::= (statement ';'?)*;
 statement ::= definition | expression;
 definition ::= 'def' def-spec '=' expression;
 def-spec ::= IDENTIFIER arg-spec*;
-arg-spec ::= IDENTIFIER;
+arg-spec ::= IDENTIFIER | '(' ')';
 expression ::= binary-expression | unary-expression;
 unary-expression ::= unop+ simple-expression;
 binary-expression ::= call-expression (binop call-expression)*;
@@ -13,6 +13,7 @@ binop ::= '*' | '/' | '+' | '-' | '?=' | '/=' | '>' | '>=' | '<' | '<=';
 unop ::= '+' | '-' | '!';
 simple-expression ::= '(' expression ')'
                     | 'true' | 'false'
+                    | '(' ')'
                     | INTEGER
                     | IDENTIFIER
                     | STRING
@@ -22,7 +23,7 @@ simple-expression ::= '(' expression ')'
                     | fn-expression
                     | do-expression;
 
-array ::= '(' ')' | '[' ']' | '[' expression (',' expression)* ','? ']';
+array ::= '[' ']' | '[' expression (',' expression)* ','? ']';
 
 if-else-expression ::= 'if' expression 'then' expression 'else' expression;
 let-in-expression ::= 'let' def-spec '=' expression ('and' def-spec '=' expression)* 'in' expression;