messing with parser, Rows call

messing around trying to get Rows call to recognize
$ syntax. got Rows to not barf, but it is interpreting $ syntax
as string values for the _field parameter as opposed to a Variable

pql/pql.peg

@@ -57,7 +57,7 @@ singlequotedstring <- ( '\\\'' / '\\\\' / '\\n' / '\\t' /  [^'\\] )*
 
 variable <- ( [[A-Z]] / '_' ) ( [[A-Z]] / [0-9] / '_' / '-' )*
 
-fieldExpr <- ( [[A-Z]] / '_' ) ( [[A-Z]] / [0-9] / '_' / '-' )*
+fieldExpr <- ( [[A-Z]] / '_' / '$' ) ( [[A-Z]] / [0-9] / '_' / '-' )*
 field <- <fieldExpr / reserved> { p.addField(text) }
 reserved <- '_row' / '_col' / '_start' / '_end' / '_timestamp' / '_field'
 posfield <- 'field='? <fieldExpr> { p.addPosStr("_field", text) }