diff --git a/parse.leg b/parse.leg
index a2bfceb..5669166 100644
--- a/parse.leg
+++ b/parse.leg
@@ -765,7 +765,7 @@ argumentList = LPAREN  m:makeMap
                 RPAREN              { $$ = m }
 
 value   =   n:FLOAT                 { $$ = newFloat(n) }
-        |   n:INTEGER               { $$ = newInteger(n) }
+        |   n:integer               { $$ = newInteger(n) }
         |   s:string                { $$ = newString(s) }
         |   s:symbol                { $$ = s }
         |   m:map                   { $$ = newMap(m) }
@@ -798,7 +798,7 @@ map     =   LCB   m:makeMap
 
 makeMap = { $$ = makeMap() }
 
-key     = IDENT | INTEGER
+key     = IDENT | integer
 
 -       =  (blank | comment)*
 
@@ -816,6 +816,9 @@ keyword = FUN | SYNTAX | VAR | SWITCH | CASE | DEFAULT | DO | FOR | IN | WHILE |
 
 IDENT   =    !keyword < [a-zA-Z_][a-zA-Z0-9_]* >   -   { $$ = intern(yytext) }
 
+integer =     i:INTEGER                             { $$ = i }
+        | '-' i:integer                             { $$ = makeInteger(-getInteger(i)) }
+
 INTEGER = '0b' < [01]+        >                 -   { $$ = makeInteger(strtol(yytext, 0,  2)) }
         | '0x' < [0-9a-fA-F]+ >                 -   { $$ = makeInteger(strtol(yytext, 0, 16)) }
         | '0'  < [0-7]+       >                 -   { $$ = makeInteger(strtol(yytext, 0,  8)) }