Problem with ?Syntax

On Sat, Feb 20, 2010 at 9:52 AM, Gabor Grothendieck

In ?Syntax [ is given as higher priority than $ but BOD$demand[3]
seems to be the same as (BOD$demand)[3] contrary to [ being higher
priority.

BOD$demand[3]

[1] 19

(BOD$demand)[3]

[1] 19

What is the rule being used here?

I think its the parser rule that defines the syntax of $ on a list. Does:

 BOD$(demand[3]) even work?

BOD$(demand[3])

Error: unexpected '(' in "BOD$("

 - no. The parser sees a $ and then gets the next token (gram.y shows
this to be a symbol or a string constant) as the thing to deal with.
Symbols  I can't think of an example where $ and [ could have
ambiguous precedence that is syntactically correct, so maybe the order
is irrelevant...

 Just for fun:

x=list(a=1,b=2)
x$"a[1]"=2
x$"a[1]"

[1] 2

x$a[1]

[1] 1


Barry