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N-Prolog Version 4.84 Release Notes

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@sasagawa888 sasagawa888 released this 14 Mar 05:26
v4.84
9cfe256

N-Prolog Version 4.84 Release Notes

This release introduces several improvements focused on usability and language stability, including new startup options, library additions, and simplification of the core language behavior.

New Startup Options

Two new command-line options have been added.

-d : Double-quote string output

When this option is specified, strings are printed using double quotes.

Example:

"hello"

By default, N-Prolog prints strings using the $ notation, which remains the standard behavior.

-f : Undefined predicate fails

With this option enabled, calling an undefined predicate will fail instead of raising an error.

Default behavior:

ERROR: undefined predicate

With -f:

fail

This option may be useful in exploratory or permissive execution environments.

Removal of set_prolog_flag

The predicate set_prolog_flag has been removed.

The reason is that such mechanisms allow the semantics of the language to change dynamically, which is undesirable for a simple and stable Prolog system.
N-Prolog aims to keep the language behavior consistent and predictable.

ISO Library Added

A new ISO library has been introduced.

  • Less frequently used ISO predicates are now provided in this library.
  • Most commonly used ISO predicates remain built-in and are available by default.

This keeps the core system compact while maintaining compatibility with the ISO standard.

Updates to the utils Library

The following predicates have been added to the utils library:

  • read_csv
  • writeln

These utilities provide convenient functionality frequently needed in practical programs.

Summary

Version 4.84 continues the goal of N-Prolog:

  • keep the core small and stable
  • avoid dynamic semantic changes
  • provide additional functionality through libraries
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