diff --git a/coml.ebnf b/coml.ebnf
index 318b4c6..f2f29f5 100644
--- a/coml.ebnf
+++ b/coml.ebnf
@@ -13,28 +13,31 @@ basicTypes ::= number | boolean | string | array | hash | patchKey | patch | "ni
 
 (* Basic Types: Number *)
 
-digit ::= #'[1-9]';
-natural ::= digit | "0" | natural "0" | digit natural;
-decInteger ::= natural | "-" natural | "+" natural;
-float ::= decInteger "f"
-        | decInteger "." natural
-        | decInteger "." natural "e" decInteger
-        | decInteger "." natural "E" decInteger;
+decDigit ::= #'[0-9]';
+nonZeroDecDigit ::= #'[1-9]';
+decInteger ::= "0" | nonZeroDecDigit decDigit*;
+
+exponentIndicator ::= "e" | "E";
+exponentPart ::= exponentIndicator decDigit+
+               | exponentIndicator "-" decDigit+
+               | exponentIndicator "+" decDigit+;
+unsignedFloat ::= decInteger "f"
+                | decInteger "." decDigit+ exponentPart*;
 
 binDigit ::= #'[0-1]';
-binNature ::= "0b" binDigit+;
-binInteger ::= binNature | "-" binNature | "+" binNature;
+binInteger ::= "0b" binDigit+;
 
 octDigit ::= #'[0-7]';
-octNature ::= "0o" octDigit+ | "0" octDigit+;
-octInteger ::= octNature | "-" octNature | "+" octNature;
+octInteger ::= "0o" octDigit+ | "0" octDigit+;
 
 hexDigit ::= #'[0-9a-fA-F]';
-hexNature ::= "0x" hexDigit+;
-hexInteger ::= hexNature | "-" hexNature | "+" hexNature;
+hexInteger ::= "0x" hexDigit+;
+
+unsignedInteger ::= decInteger | binInteger | octInteger | hexInteger;
+signedInteger ::= unsignedInteger | "-" unsignedInteger | "+" unsignedInteger;
+signedFloat ::= unsignedFloat | "-" unsignedFloat | "+" unsignedFloat;
 
-integer ::= decInteger | binInteger | octInteger | hexInteger;
-number ::= integer | float;
+number ::= signedInteger | signedFloat;
 
 (* Basic Types: Boolean *)
 
@@ -56,7 +59,7 @@ array ::= "[" splitter? arrayElements splitter? "]"
 
 keyCharStart ::= #'[a-zA-Z_]';
 
-keyCharMiddle ::= keyCharStart | digit | "0" | "_";
+keyCharMiddle ::= keyCharStart | decDigit;
 key ::= keyCharStart keyCharMiddle*;
 hashElement ::= (whitespaces?) key (splitter?) ":" (splitter?) expr;
 hash ::= hashElement | hashElement eol+ hash;
@@ -73,9 +76,9 @@ imports ::= import | import eol+ imports;
 (* Patch *)
 
 patchKey ::= patchKey "." key
-           | patchKey "[" whitespaces? (string | integer) whitespaces? "]"
-           | patchKey "[" whitespaces? integer whitespaces? ".." whitespaces? integer whitespaces? "]"
-           | patchKey "[" whitespaces? integer whitespaces? "..." whitespaces? integer whitespaces? "]"
+           | patchKey "[" whitespaces? (string | signedInteger) whitespaces? "]"
+           | patchKey "[" whitespaces? signedInteger whitespaces? ".." whitespaces? signedInteger whitespaces? "]"
+           | patchKey "[" whitespaces? signedInteger whitespaces? "..." whitespaces? signedInteger whitespaces? "]"
            | key;
 
 patchReplace ::= patchKey whitespaces? "=" splitter? expr;