diff --git a/doc/GRAMMAR b/doc/GRAMMAR
index 3439b24..4f287ee 100644
--- a/doc/GRAMMAR
+++ b/doc/GRAMMAR
@@ -1,6 +1,8 @@
 program:	{ section | statement }
 
-section:	"." WORD newline
+section:	"." section_name newline
+
+section_name:	WORD
 
 newline:	[ space ] NEWLINE
 
@@ -8,17 +10,17 @@ space:		SPACE { SPACE }
 
 statement:	( function | space [ instruction ] ) newline
 
-function:	name [ space ] ":"
+function:	function_name [ space ] ":"
 
-name:		WORD
+function_name:	WORD
 
-instruction:	operator [ operand_list ]
+instruction:	instruction_name [ space [ operand_list ] ]
 
-operator:	WORD
+instruction_name:	WORD
 
-operand_list:	operand { "," operand }
+operand_list:	operand [ space ] { "," [ space ] operand [ space ] }
 
-operand:	[ space ] ( value | address ) [ space ]
+operand:	value | address
 
 value:		symbol | register | immediate
 
@@ -26,6 +28,10 @@ symbol:		WORD
 
 register:	"%" WORD
 
-immediate:	"$" NUMBER
+immediate:	"$" [ sign ] NUMBER
 
-address:	"[" [ space ] value [ value ] [ "+" [ space ] offset [ space ] ] "]"
+address:	"[" [ space ] [ sign [ space ] ] value [ space ] [ offset [ space ] ] "]"
+
+sign:		( "+" | "-" )
+
+offset:		sign [ space ] value