Improve auto-complete for this case #186 : adjust grammar

Author: xonixx

Diff for: src/main/java/intellij_awk/Awk.bnf

@@ -502,7 +502,7 @@ lvalue           ::= gawk_var_name | DOLLAR expr
 
 // XXX this covers a[1][2][3] like in Gawk
 // XXX awk only supports a[1]
-private gawk_var_name ::= var_name (LBRACKET expr_lst RBRACKET)*
+//private gawk_var_name ::= var_name (LBRACKET expr_lst RBRACKET)*
 
 // XXX for some reason the below makes it terribly slow or hanging on profile5.awk
 /*private gawk_var_name ::= var_name (subscript_start RBRACKET)*
@@ -512,6 +512,15 @@ private subscript_start ::= LBRACKET expr_lst {
 }
 private recover_on_rbracket ::= !RBRACKET*/
 
+private gawk_var_name ::= var_name (subscript_start RBRACKET)*
+private subscript_start ::= LBRACKET expr_lst_inner {
+    pin=1
+}
+private expr_lst_inner ::= expr_lst {
+//    recoverWhile=recover_on_rbracket
+}
+//private recover_on_rbracket ::= !RBRACKET
+
 private var_name ::= builtin_var_name | user_var_name
 
 builtin_var_name ::= SPECIAL_VAR_NAME | SPECIAL_VAR_NAME_GAWK