Module facts 

Fact-table lookup (FACT_TABLE.md, Stages A–C): the generic enumerator for a predicate compiled to a .rodata table instead of one function per clause. Same observable behavior as the per-clause facts — solution order = program order, choice-point backtracking — mirroring between/3’s shape.

A table cell is one word. Immediate columns (atom / i61-int) are stored inline and unified directly. Non-immediate columns (compound, list, float, big-int — Stage C) are stored as a blob reference: a STR/LST/FLT/ BIG word whose payload indexes a per-predicate .rodata serialized blob (the copyterm/TermBuf format). fact_scan restores such a cell onto the heap via restore_cells before unifying — so the cell tag (atom/int vs the pointer tags) tells the two cases apart with no extra metadata.

Stage B’s first-argument index applies only when column 0 is all-immediate; otherwise (or for an unbound/non-immediate query arg) the scan covers all rows. Either way matching rows are visited in program order.

Delivery to the continuation is a musttail in the GENERATED entry/retry functions, not here: these helpers only find/bind a row and push the choice point, then RETURN. That return pops their frame before the generated code tail-calls the continuation, so recursion through a fact predicate (e.g. edge in a recursive path/2) keeps a constant C stack.

Functions

plg_rt_fact_first^⚠

Compiled entry: snapshot the args + continuation into a control frame, pick the row range to scan (binary search on the index when the first arg is a bound atom/int, else all rows), then find the first matching row. Returns 1 if a solution was set up (the generated entry then musttails the continuation), 0 if no row matches.

plg_rt_fact_next^⚠

Choice-point retry: restore the saved continuation (the driver may have overwritten m.k_fn), then resume the scan from the frame’s cursor.