Tokeniser directives

The tokeniser directives are defined in the RFC 2.0.

#atom

declare char sequences as atoms, avoiding initial lower case constraint.

#node

declare char sequences as nodes, avoiding initial upper case constraint.

#show

declare query paths for batch querying.

#showif

Zdatr 2.0 addition, included in RFC 2.0: declare conditional query paths for batch querying, one extensional equation per line.

#query

Zdatr 2.0 addition, not included in RFC 2.0: list specific Node:Path pair queries one per line.

#hide

#vars

declare variables, including operations over prior definitions:

 #vars $a: a b c.
 vars $b: $a d e f.

The definition of $b here is equivalent to

 #vars $b: a b c d e f.

The 'subtraction' operation is also allowed:

 #vars $a: a b c d e f.
 #vars $b: $a - d f.

The definition of $b in this case is equivalent to

 #vars $b: a b c e .

i. e. the set of values of $a without atoms 'd' and 'f'.