Provide a regression test entry-point for pretty-printing output

Occasionally bare strings can be annoyingly ugly

Fix various breakages caused by 86935be3f42

Along the way adjust WORD_CANCEL_CONV to tidy up after itself so
that when it sees

x + y + z + u = a + y + b + u

it doesn't turn it into

x + y + z + u - y - u = a + y + b + u - y - u

and wait for something else to clean it up, but rather goes straight
to

x + z = a + b

Make Unicode negation work on words again (fallout from 9368591)

With test-case, and some cleaning up of selftest.sml in src/n-bit

Fix more regression tests broken by testutils API change

Get src/n-bit to pass its selftest given tight-equality

Fix n-bit's selftest's qtest to report parse errors with locations

Change type_abbrev to not alter printing behaviour

If printing of abbreviations is desired, users must now use
type_abbrev_pp.

Closes #599

Don't export ERR from HolKernel

Improving naming of bit-vector signed division constants.

This renaming introduces incompatibilities:

• words$word_sdiv -> words$word_quot (this is proved to be related to int_quot for a non-zero divisor).
• words$word_srem -> words$word_rem (this is proved to be related to int_rem for a non-zero divisor).
• integer_word$word_sdiv (this is a new constant defined directly in terms of int_div).
• words$word_smod -> integer_word$word_smod (this is now defined directly in terms of int_mod).

Fix Datatype parsing array[number] type

Includes test-case

Tidy up some selftests, making output prettier

Fix many selftests to have prettier output

Some function in bitstringSyntax are now based on Arbnum.num instead of Int.int.

The old versions were vulnerable to Overflow exceptions.

Various tweaks to bit-vector development.

NOTE: It is possible that some bit-vector proofs may break, due to subtle changes in bit-vector simplification.

The selftest script now tests calls to WORD_GROUND_CONV. (This conversion's flag is also set to false for use outside of wordsLib.)

Some unused tools have been removed from blastLib.

Move bitTheory into src/num/extra_theories and move evaluations theorems in wordsLib further up the build sequence.

Includes some tidying-up work.

This closes issue #120. Evaluation for "toNum" and "toString" can now be enabled by loading up stringLib (or, more precisely, ASCIInumbersLib), without the need to load up wordsLib.

This check-in can be viewed as finishing off the (many) loose ends left over from work on issue #70.

Selftest demonstrating problem of #106.

Use testutils in n-bit/selftest.sml

Adopt ML-style syntax for case expressions and use freed up "||" for bitwise-or. See issue #24.

Fix WORD_MUL_LSL_CONV so that it works with ``:'a word`` terms, i.e. words of
unspecified width.

Add wordsLib.WORD_CANCEL_ss, which is a fancy version of WORD_ARITH_EQ_ss.

WORD_CANCEL_ss is now used during the preliminary simplification stage of
BBLAST_PROVE, which enables the procedure to better handle simple arithmetic
properties (i.e. avoiding unnecessary bit-blasting).

For example: we have

> SIMP_CONV (srw_ss() ++ wordsLib.WORD_CANCEL_ss) []
``2w * a - b * 2w + -7w = b + 1w + a``
<<HOL message: inventing new type variable names: 'a>>
val it =
|- (2w * a − b * 2w + -7w = b + 1w + a) ⇔ (3w * b + 8w = a):
thm

which is preferable to

> SIMP_CONV (srw_ss() ++ wordsLib.WORD_ARITH_EQ_ss) []
<<HOL message: inventing new type variable names: 'a>>
val it =
|- (2w * a − b * 2w + -7w = b + 1w + a) ⇔ (a + -3w * b + -8w = 0w):
thm

Fix glitch in WORD_AND_CANON_CONV.

A few extra theorems.

Cosmetic changes.

Added new operations for shifting by a bit-vector value, namely:

LSL: <<~
LSR: >>>~
ASR: >>~
ROR: #>>~
ROL: #<<~

These are supported by the procedures in blastLib. For example, one can prove

w <+ 10w /\ s <+ 3w ==> w <<~ (s + 1w) <+ 73w : word16

The time-complexity is a pretty shocking but "simple" 32-bit problems seem to
be okay. NB. ROR and ROL only bit-blast with word sizes that are a power of
two.

Added a new conversion WORD_MOD_BITS_CONV for mapping applications of
``word_mod w (n2w n)`` into ``(h -- 0) w`` where n is a power of two.

Also added support for bit-blasting arbitrary multiplication, but the word-size
limit is set to 8 bits by default. Things seem to be just about feasible with
that limit (and become horrendously slow after that).

To improve performance, the conversion BBLAST_CONV does not have exactly the
same coverage as before. For backward compatibility, a conversion
EBLAST_CONV (which calls SAT at every bit position) is now available.

Improvement to handling of counterexamples under BBLAST_PROVE. (Word variables
that do not appear in the SAT theorem are assigned to 0w).

Small tidy-up.

Changes to WORD_MUL_LSL_CONV in an attempt to make it more robust - it was
failing on some corner cases. It should also be a bit quicker now too.

Minor bug fix.

Tweak.

Added Tactical.PRED_ASSUM. It's similar to PAT_ASSUM but uses a predicate to
pick the assumption.

Added blastLib.FULL_BBLAST_TAC, which attempts to use "blastable" assumptions.

Make blastLib.BBLAST_PROVE smarter with respect to counterexamples (existential
goals). For example,

> blastLib.BBLAST_PROVE ``?x y. x + y = 12w : word8``;
val it = |- ?x y. x + y = 12w: thm

is now possible, and we also have:

> blastLib.BBLAST_PROVE ``x < y = x <=+ y : word8``;
Found counterexample:

y -> 255w

and

x -> 0w

Exception- SAT_cex |- (0w < 255w <=> 0w <=+ 255w) <=> F raised

The printing of counterexamples is controlled by the trace
"print blast counterexamples".

Add fcpSyntax and tidy up related code.

Clean up type grammars to reflect reality of suffixes as tightest operators.

Also, fix a minor pretty-printing bug that was affecting types like

('a + 'b) [32]

and document this in src/n-bit/selftest.sml

Fix bug concerning interaction of arrays and other suffixes.

In the process, make it clear that suffixes really do have to be the
tightest operators in the grammar.

Also, add a type-parsing test for array types to
src/n-bit/selftest.sml.

Thanks to Anthony for the report.

Add BBLAST_PROVE.

Add FST and SND rewrites for BLAST_CONV. This help when proving things about
word_rrx, e.g.

``SND (word_rrx (T,v:word32)) = v >>> 1 !! 0x80000000w``

Fix glitch in WORD_OR_CANON_CONV where, for example. ``0x20000000w !! 0w``
would not be converted to ``0x20000000w``.

Fix problem with BBLAST_CONV raising an Empty exception on certain terms.
This was due to dpll.DPLL_TAUT which, for example, raises Empty on

``if b then T else T``

This case has been avoided by adding this theorem as a rewrite. To avoid any
similar problems, the call to dpll.DPLL_TAUT is now made under Lib.trye.

Thanks to Tjark Weber for reporting this problem.

Fix handling of quantifiers in BBLAST_CONV. For example, was previously
converting ``!a. P a`` to ``!a. P a = T`` instead of ``(!a. P a) = T``.

Few other minor tweaks.

Fix a non-termination (stack overflow) bug. Example added to selftest.

Slightly tidy up output of selftest.

Remove left over junk.

Fix n-bit selftest (had some junk(?) at end) and make it prettier.

Added a bit-blasting conversion: BBLAST_CONV. This goes beyond the
capabilities of WORD_BIT_EQ_CONV by expanding out additions / subtractions.
This allows the new conversion to automatically handle small but tricky bit
vector goals. For example:

``(x && 3w = 0w:word32) ==> ((x + 4w * y) && 3w = 0w)``

and

``!a:word8. a <+ 4w /\ b <+ a /\ c <=+ 5w ==> (b + c) <=+ 7w``

(These aren't provable with wordsLib.WORD_DECIDE.)

Obviously bit-blasting is a brute force approach, so the new conversion should
be used with care. It will only work well for smallish word sizes and when
there is only and handful of additions around. It is also "eager" -- additions
are expanded out even when not strictly necessary. For example, in

``(a + b) <+ c /\ c <+ d ==> (a + b) <+ d:word32``

the sum ``a + b`` is expanded. Users may be able to achieve speed-ups by first
introducing abbreviations and then proving general forms, e.g.

``x <+ c /\ c <+ d ==> x <+ d:word32``

The conversion handles most operators, however, the following are not covered /
interpreted:

-- Type variables for word lengths, i.e. terms of type ``:'a word``.

-- General multiplication, i.e. ``w1 * w2``. Multiplication by a literal is
okay, although this may introduce many additions.

-- Bit field selections with non-literal bounds, e.g. ``(exp1 -- exp2) w``.

-- Shifting by non-literal amounts, e.g. ``w << exp``.

-- ``n2w exp`` and ``w2n w``. Also w2s, s2w, w2l and l2w.

-- word_div, word_sdiv, word_mod and word_log2.