Modules

Module	Source File	Description
b_tree	b_tree.f90	An open B+-tree. Pure data plus the open unit — the comparator and its context are stateless and supplied per call, so a handle can be closed and reopened freely and carries nothing un-persistable. A forward cursor over entries in ascending `(key,payload)` order. Obtained from `bt_first` (whole tree) or `bt_seek` (lower bound on a key); advanced and read with `bt_next`.
b_tree_sm	b_tree_sm.f90
clib_wrap	clib_wrap.f90	atomic rename/replace (same filesystem) unlink a file or remove an empty directory create one directory (mode 0777 & umask on POSIX) does the path exist? recursively remove a directory tree flush a file's data to stable storage flush a directory's entries to stable storage set a file's length (shrink or grow) try (non-blocking) to take an advisory lock release an advisory lock and close its handle downgrade an exclusive advisory lock to shared is standard input a terminal?
clib_wrap_impl	clib_wrap_sm.f90
cmdgraph	cmdgraph.f90	Library version. `major` and `minor` are synchronised across all implementations; `patch` may differ per implementation. Compile-time library version constant. Declarative argument specification attached to a command. Preferred over direct initialisation — use the `arg_is_int` / `arg_is_real` / `arg_is_char` / `arg_is_rest` constructor functions. When a command has an `args=` spec the engine validates count and types before invoking the action; failure short-circuits with `RC_ERROR`. Read-only description of one command in the current state, returned by `engine_t%available_commands`. The result depends only on the state name; safe to cache keyed by state name after `finalize`. State-graph driven command interpreter. Read more…
cmdgraph_sm	cmdgraph_sm.f90
dlist	dlist.f90	Doubly-linked list with polymorphic element storage. Iterate with `iterate` / `reverse_iterate`, or access by index with `get`. Abstract base for list element data. Extend this type to store custom data. Node holding a single `integer` value. Node holding a single `real(8)` value. Node holding a `real(8)` rank-1 array. Node holding a `real(8)` rank-2 array. Node holding an allocatable `character` string. Construct an integer node. Construct a real(8) scalar node. Construct a real(8) rank-1 array node. Construct a real(8) rank-2 array node. Construct a character node. Generic node constructor — dispatches on argument type. Visitor procedure signature for `iterate` / `reverse_iterate`. Set `ok = .false.` to stop iteration early.
dlist_sm	dlist_sm.f90
sql	sql.f90	One AND-group of conditions. A WHERE clause is a disjunction (OR) of these groups; a row matches the clause iff it matches every condition of some group (disjunctive normal form — no parentheses needed). The outcome of executing one statement. A SELECT fills `colnames` and the `(nrows, ncols)` `cells` grid; a DML statement fills `count`; DDL fills `message`. Both the REPL and the test suite consume this same structure, so output is asserted directly rather than scraped from text. source line -> token stream source line -> one statement AST statement AST -> result (drives the engine) source line -> result (lex + parse + exec) result -> printed to a unit (the REPL renderer)
sql_base	sql_base.f90	Lower-case an ASCII string (for case-insensitive keyword matching). `.true.` if token `t` is the (case-insensitive) keyword `kw`. `.true.` if token `t` is the punctuation `p`. Record an error: set `stat` (when present) to `code` and copy `msg` into `errmsg` (when present, truncated to its length). Decimal text of an integer.
sql_executor	sql_exec.f90	Gathering context for a `db_scan` (and reused by the cursor path): the table being read, the WHERE clause to apply, and the growing set of matching rows (ids + record buffers).
sql_parser	sql_parse.f90
sqr	sqr.f90	A (possibly composite) secondary index. The key is the member column bytes concatenated in declared order; a single-column index is just arity 1. `unique` enforces that no two live rows share a key. One open table: schema, derived layout, open units and index set. One undo record captured before a transaction overwrites part of a base file. A REGION record stores the original bytes of an in-place overwrite (rollback writes them back); an EXTEND record stores only the original file length (rollback truncates appended bytes away). Module-private — exposed only as a component of `journal_t`. Pre-transaction snapshot of one table's in-memory counters. The undo journal restores file bytes; these cached values (high-water row id, live count, blob append position) are advanced in memory by row mutations and are not on disk per-write, so a rollback restores them from here — the record analogue of `bt_reload` for the index trees. Module-private — exposed only as a component of `journal_t`. Per-database rollback journal. Opaque to callers, carried as a component of `db_t`; driven by the `txn_` / `jrnl_` procedures. The file `<db>/_journal.dat` is a reusable sidecar — a hot (valid) journal exists iff a transaction is in flight or a crash interrupted one. An open database handle. Obtain with `db_open`; release with `db_close`. A handle is bound to one directory for its lifetime. A forward (ascending) cursor over the live rows of a table in the key order of one of its single-column indices. Obtain it from `db_open_cursor` (the whole index) or `db_find_range` (an inclusive `[lo,hi]` band), then pull rows with `db_cursor_next` until it reports exhaustion — the pull complement to the `db_scan` callback. Read more…
sqr_base	sqr_base.f90
sqr_admin	sqr_admin.f90
sqr_index	sqr_index.f90
sqr_journal	sqr_journal.f90
sqr_record	sqr_record.f90
sqr_rowbuf	sqr_rowbuf.f90
sqr_table	sqr_table.f90
sqr_fault	sqr_fault.f90
sqr_fault_off	sqr_fault_off_sm.f90