Input/output from/to constant terms

Input/output from/to constant terms

These built-in predicates enable a Prolog term to be input from or output to a Prolog constant term (atom, character list or character code list). All these predicates can be defined using constant term streams (section 7.11). They are however simpler to use.

7.15.1 read_term_from_atom/3, read_from_atom/2, read_token_from_atom/2

Templates

: read_term_from_atom(+atom ?term, +read_option_list) read_from_atom(+atom, ?term) read_token_from_atom(+atom, ?nonvar)

Description

Like read_term/3, read/2 (section 7.14.1) and read_token/2 (section 7.14.3) except that characters are not read from a text-stream but from Atom; the atom given as first argument.

Errors

Atom is a variable instantiation_error

Atom is neither a variable nor an atom type_error(atom, Atom)

see associated predicate errors (section 7.14.1) and (section 7.14.3)

Portability

GNU Prolog predicates.

7.15.2 read_term_from_chars/3, read_from_chars/2, read_token_from_chars/2

Templates

: read_term_from_chars(+character_list ?term, +read_option_list) read_from_chars(+character_list, ?term) read_token_from_chars(+character_list, ?nonvar)

Description

Like read_term/3, read/2 (section 7.14.1) and read_token/2 (section 7.14.3) except that characters are not read from a text-stream but from Chars; the character list given as first argument.

Errors

Chars is a partial list or a list with an element E which is a variable instantiation_error

Chars is neither a partial list nor a list type_error(list, Chars)

an element E of the Chars list is neither a variable nor a character type_error(character, E)

see associated predicate errors (section 7.14.1) and (section 7.14.3)

Portability

GNU Prolog predicates.

7.15.3 read_term_from_codes/3, read_from_codes/2, read_token_from_codes/2

Templates

: read_term_from_codes(+character_code_list ?term, +read_option_list) read_from_codes(+character_code_list, ?term) read_token_from_codes(+character_code_list, ?nonvar)

Description

Like read_term/3, read/2 (section 7.14.1) and read_token/2 (section 7.14.3) except that characters are not read from a text-stream but from Codes; the character code list given as first argument.

Errors

Codes is a partial list or a list with an element E which is a variable instantiation_error

Codes is neither a partial list nor a list type_error(list, Codes)

an element E of the Codes list is neither a variable nor an integer type_error(integer, E)

an element E of the Codes list is an integer but not a character code representation_error(character_code, E)

see associated predicate errors (section 7.14.1) and (section 7.14.3)

Portability

GNU Prolog predicates.

7.15.4 write_term_to_atom/3, write_to_atom/2, writeq_to_atom/2,
write_canonical_to_atom/2, display_to_atom/2, print_to_atom/2,
format_to_atom/3

Templates

: write_term_to_atom(?atom, ?term, +write_option_list) write_to_atom(?atom, ?term) writeq_to_atom(?atom, ?term) write_canonical_to_atom(?atom, ?term) display_to_atom(?atom, ?term) print_to_atom(?atom, ?term) format_to_atom(?atom, +character_code_list_or_atom, +list)

Description

Similar to write_term/3, write/2, writeq/2, write_canonical/2, display/2, print/2 (section 7.14.6) and format/3 (section 7.14.7) except that characters are not written onto a text-stream but are collected as an atom which is then unified with the first argument Atom.

Errors

Atom is neither a variable nor an atom type_error(atom, Atom)

see associated predicate errors (section 7.14.6) and (section 7.14.7)

Portability

GNU Prolog predicates.

7.15.5 write_term_to_chars/3, write_to_chars/2, writeq_to_chars/2,
write_canonical_to_chars/2, display_to_chars/2, print_to_chars/2,
format_to_chars/3

Templates

: write_term_to_chars(?character_list, ?term, +write_option_list) write_to_chars(?character_list, ?term) writeq_to_chars(?character_list, ?term) write_canonical_to_chars(?character_list, ?term) display_to_chars(?character_list, ?term) print_to_chars(?character_list, ?term) format_to_chars(?character_list, +character_code_list_or_atom, +list)

Description

Similar to write_term/3, write/2, writeq/2, write_canonical/2, display/2, print/2 (section 7.14.6) and format/3 (section 7.14.7) except that characters are not written onto a text-stream but are collected as a character list which is then unified with the first argument Chars.

Errors

Chars is neither a partial list nor a list type_error(list, Chars)

see associated predicate errors (section 7.14.6) and (section 7.14.7)

Portability

GNU Prolog predicates.

7.15.6 write_term_to_codes/3, write_to_codes/2, writeq_to_codes/2,
write_canonical_to_codes/2, display_to_codes/2, print_to_codes/2,
format_to_codes/3

Templates

: write_term_to_codes(?character_code_list, ?term, +write_option_list) write_to_codes(?character_code_list, ?term) writeq_to_codes(?character_code_list, ?term) write_canonical_to_codes(?character_code_list, ?term) display_to_codes(?character_code_list, ?term) print_to_codes(?character_code_list, ?term) format_to_codes(?character_code_list, +character_code_list_or_atom, +list)

Description

Similar to write_term/3, write/2, writeq/2, write_canonical/2, display/2, print/2 (section 7.14.6) and format/3 (section 7.14.7) except that characters are not written onto a text-stream but are collected as a character code list which is then unified with the first argument Codes.

Errors

Codes is neither a partial list nor a list type_error(list, Codes)

see associated predicate errors (section 7.14.6) and (section 7.14.7)

Portability

GNU Prolog predicates.

Copyright (C) 1999-2002 Daniel Diaz.

Chapters 9 and 10 : Copyright (C) 2002-2003 INRIA, Rémy Haemmerlé.

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