doc: show release version in LDocs column headings.

* build-aux/config.ld.in (project): Add release version.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
functional: improve lambda expressiveness.

* specs/functional_spec.yaml: Specify new behaviours with omitted
optional '=', and '_' alias argument.
* lib/std/functional.lua (lambda): Strip more useless whitespace
in parsing to improve memoize cache hits.
Support omitting leading '=' when first non-whitespace of lambda
string is '_'.
Add '_' alias to '_1' for lambda string compiled expressions.
Update LDocs.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
functional: generalize reduce to any table.

* specs/functional_spec.yaml (reduce): Specify optional iterator
argument defaulting to std.pairs.
Specify requirement for std.ielems when ignoring reduced table
keys.
* specs/operator_spec.yaml (set): Specify behaviours for a new
table element setting operator.
* specs/container_spec.yaml: Use appropriate iterator functions
for new reduce API.
* lib/std/functional.lua (reduce): Diagnose optional iterator
argument to std.pairs.
(fold): Copy old reduce implementation into deprecated call.
* lib/std.lua.in (barrel): Adjust accordingly.
* lib/std/base.lua (reduce): Default optional iterator argument
to std.pairs.
Pass all iterator results to accumulator function.
Adjust all clients.
* lib/std/operator.lua (set): Implement according to new specs.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
refactor: rename operator.deref to operator.get.

* specs/operator_spec.yaml (deref): Rename from this...
(get): ...to this.
* lib/std/operator.lua (deref): Rename from this...
(get): ...to this.
Adjust all callers.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
specs: use correct Specl > 13 arity for bad argument errors.

Now that Specl's badargs module is generating examples with
the correct messages, we can now say 'no more than 0 arguments'.
* lib/std/debug.lua (toomanyargmsg): Return singular 'argument'
in error message only for exactly 1 expected argument, otherwise
plural.
* bootstrap.conf (buildreq): Bump specl requirement.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>