^ ^                 ^ ^
=(o.o)=  ~byakuren  =(o.o)=
  m m                 m m

ISO Predicate Checklist (flowlog.c)

This file tracks Flowlog’s progress towards ISO/IEC 13211-1 behavior.

This checklist is intentionally self-contained.

How to validate conformance

Flowlog is primarily validated with:

• In the full Flowlog repository: the regression tests and the INRIA ISO Prolog suite (see CONFORMANCE.md)

Optional external cross-checks (not required for “ISO Prolog”, but useful in practice):

• Trealla Prolog (tpl) and Scryer Prolog for behavioral comparisons on specific programs/benchmarks

Scope: what ISO means here

ISO/IEC 13211-1 describes the language and its built-in predicates, not the interactive top-level UI.

Flowlog targets ISO semantics for:

• Terms, unification, and control constructs
• Arithmetic evaluation (is/2) and ISO arithmetic errors
• Dynamic database predicates (asserta/1, assertz/1, retract/1, abolish/1, clause/2, current_predicate/1, …)
• Streams and term I/O (open/3, close/1, read_term/3, write_term/3, stream selection, …)
• Flags (current_prolog_flag/2, set_prolog_flag/2) including ISO error behavior for invalid values

Top-level notes (non-ISO)

The REPL behavior is designed to be test-friendly and scriptable:

• It prints all solutions (there is no interactive ; prompt).
• It supports the common consult shorthand ([file].) for loading one or more files (a top-level convenience; not part of ISO).

These are UI choices and do not affect ISO program semantics inside a loaded program.

Prolog flags (core)

Flags implemented by current_prolog_flag/2 + set_prolog_flag/2 include:

• unknown (error|warning|fail)
• occurs_check (true|false)
• char_conversion (on|off)
• double_quotes (atom|codes|chars)
• character_escapes (true|false)
• debug (on|off)

Read-only informational flags include:

• bounded
• max_arity
• integer_rounding_function

Flowlog extensions (non-ISO)

Flowlog adds parallelism controls via Prolog flags (the default is flowlog_parallel_profile=fast):

• flowlog_parallel
• flowlog_parallel_profile
• flowlog_parallel_or, flowlog_parallel_or_order, flowlog_parallel_or_nesting
• flowlog_parallel_and
• flowlog_parallel_max_depth

See PARALLELISM.md for details.

Known deviations / limitations

If you hit conformance surprises, start here:

• The top-level UI is not ISO-specified; differences from other REPLs are expected.
• Some non-ISO convenience features (e.g. consult/1 or [user]. clause mode) may be absent even if the ISO core is correct.
• For a full built-in predicate list, see PREDICATES.md.