diff --git a/src/preserves/pegs.nim b/src/preserves/pegs.nim
index abfacc7..421e4e5 100644
--- a/src/preserves/pegs.nim
+++ b/src/preserves/pegs.nim
@@ -34,7 +34,7 @@ grammar "Preserves":
   Boolean <- "#f" | "#t"
 
   nat <- '0' | (Digit-'0') * *Digit
-  int <- ?'-' * nat
+  int <- ?('-'|'+') * nat
   frac <- '.' * +Digit
   exp <- 'e' * ?('-'|'+') * +Digit
   flt <- int * ((frac * exp) | frac | exp)