If a position in TermPos is a variable, the validation of the corresponding part of Term succeeds. This matches the term_expansion/4 treats "unknown" layout information. If part of a TermPos is given, then all its "from" and "to" information must be specified; for example, string_position(X,Y) is an error but string_position(0,5) succeeds. The position values are checked for being plausible -- e.g., string_position(5,0) will fail.

This should always succeed:

read_term(Term, [subterm_positions(TermPos)]),
valid_term_position(Term, TermPos)

Arguments:

Term	- Any Prolog term including a variable).
TermPos	- The detailed layout of the term, for example from using read_term(Term, subterm_positions(TermPos).

Errors

- existence_error(matching_rule, Subterm) if a subterm of Term is inconsistent with the corresponding part of TermPos.

See also

- read_term/2, read_term/3, term_string/3

- expand_term/4, term_expansion/4, expand_goal/4, expand_term/4

- clause_info/4, clause_info/5

- unify_clause_hook/5