# -*- coding: utf-8 -*-
#+TITLE: Upgrading from Spot 1.2.6
#+DESCRIPTION: Help for upgrading code to Spot 2.0
#+INCLUDE: setup.org
#+HTML_LINK_UP: index.html

This page is for people who have code written for Spot 1.2.6, and
would like to upgrade to Spot 2.0.  The changes listed here will
probably also apply to code written using older Spot 1.x versions.

This page is in no way exhaustive.  The main intent is just to list
the major changes that have occurred in the library since version
1.2.6, so that one can more easily update existing code.  The focus is
based on features that appear to be commonly used, based on our the
experience of updating a couple of projects that are using Spot.

* Overview of the changes

  Let's begin by just trying to summarize what has changed between
  Spot 1.2.6 and Spot 2.x, just to get an idea of what will need to be
  updated.

  1. [[#cpp17][Spot now compiles using the C++17 standard]].  Compliant compilers
     are sufficiently widespread now that this should not be an issue.

  2. The layout of the source-tree and the layout of the installed
     header files have been completely overhauled, and several header
     files have been renamed.  An early step of upgrading existing
     code dependent on Spot will therefore be to [[#includes][update all the
     =#include=]].

  3. [[#buddy][The customized version of BuDDy distributed with Spot has been
     renamed]] to not clash with any regular version installed on the
     system.

  4. [[#formulas][The implementation of LTL formulas has been rewritten]].

     They are no longer pointers but plain objects that performs their
     own reference counting, freeing the programmer from this tedious
     and error-prone task.  They could be handled as if they were
     shared pointer, with the small difference that they are not using
     C++'s standard shared pointers.

     All operators are now implemented using a single type of node,
     with a field that can be used to make a switch instead of what
     used to require visitors.

  5. Allocated object that are large or expected to have a long life
     (such as automata, BDD dictionaries, accepting runs) are now
     [[#shared_ptr][returned using shared pointers]].

  6. Spot used to be centered around the concept of TGBA
     (Transition-based Generalized Büchi Automata), i.e.,
     \omega-automata in which a run is accepting if it visits
     infinitely often one transition in each defined accepting set of
     transitions.  This was implemented as a =tgba= class.

     In Spot 2.0, each automaton can have a different acceptance
     condition: this includes well known acceptance conditions such as
     Büchi, co-Büchi, Rabin, Streett, or parity, but it could also be
     an arbitrarily complex Boolean combination of those.  [[#tgba-twa][The central
     automaton concept is now called T\omega{}A]] (for Transition-based
     \omega-Automata), and implemented as a =twa= class.  The =tgba=
     class does not exist anymore: a TGBA is just a T\omega{}A in
     which the acceptance condition has been set to "generalized
     Büchi".

     While the gained generality on acceptance conditions allows us to
     write algorithms that may work on any acceptance condition, Spot
     still contains algorithms that work only on a particular
     acceptance condition.  Those restrictions have to be ensured
     using preconditions: the acceptance condition does not appear in
     the type of the C++ object representing the automaton.

  7. [[*Various renamings][Several class, functions, and methods, have been renamed]].  Some
     have been completely reimplemented, with different interfaces.
     In particular the =tgba_explicit_*= family of classes
     (=tgba_explicit_formula=, =tgba_explicit_number=,
     =tgba_explicit_string= used to encode a TGBA using a graph whose
     state was named using LTL formulas, integers, or strings) are
     replaced by a =twa_graph= class in which the representation is
     more compact and efficient, but where states are necessarily
     numbered.  Many algorithms have been rewritten on top of this
     =twa_graph= class, and this simplified them a lot.

* Upgrading to C++17
  :PROPERTIES:
  :CUSTOM_ID: cpp17
  :END:

  Because Spot now relies on C++17 features, programs that use Spot
  should at least be compiled using this version (or a later one) of
  the language.

  This is usually done by passing the option =-std=c++17= to =g++= or
  =clang++=.

  Upgrading from C++98, C++03, C++11, or C++14 to C++17 should be
  relatively smooth as the language is /mostly/ backward compatible.

* Upgrading =#include= directives
  :PROPERTIES:
  :CUSTOM_ID: include
  :END:

** Adjusting the search path
  :PROPERTIES:
  :CUSTOM_ID: include-search
  :END:


If Spot 1.2.6 was installed in =/usr/local=, its headers are
in =/usr/local/include/spot=.   One would to write include statements
such as
#+BEGIN_SRC C++
  #include <tgba/tgba.hh>
  #include <ltl/formula.hh>
#+END_SRC
and then compile with =-I /usr/local/include/spot/= to make sure that
the Spot headers were found.  Headers in Spot would also include other
header in Spot by using names relative to the =/usr/local/include/spot/=
directory.

If Spot 2.0 is installed in =/usr/local=, its headers are still in
=/usr/local/include/spot= however the =spot/= directory is and should
always be used to refer to the header:
#+BEGIN_SRC C++
  #include <spot/twa/twa.hh>      // the new name of tgba/tgba.hh
  #include <spot/tl/formula.hh>   // the new name of ltl/formula.hh
#+END_SRC
Now compilation should only be done with option =-I
/usr/local/include=, which is usually already included by default.

** Renaming headers files
   :PROPERTIES:
   :CUSTOM_ID: includes
   :END:

The following table shows all the headers installed by Spot 1.2.6, and
the corresponding name to include in Spot 2.0.  Some of the new names
do not exactly correspond to a renaming, but instead correspond to headers
that provide a function with a similar service.


|------------------------------------+------------------------------------+--------------------------------------------------|
| old name                           | new name or suggested replacement  | comment                                          |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~bdd.h~                            | ~bddx.h~                           | customized version of BuDDy                      |
| ~bvec.h~                           | ~bvecx.h~                          | customized version of BuDDy                      |
| ~fdd.h~                            | ~fddx.h~                           | customized version of BuDDy                      |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~dstarparse/public.hh~             | ~spot/parseaut/public.hh~          | single parser for all automata                   |
| ~eltlparse/public.hh~              |                                    | not supported anymore                            |
| ~iface/dve2/dve2.hh~               | ~spot/ltsmin/ltsmin.hh~            |                                                  |
| ~kripke/fairkripke.hh~             | ~spot/kripke/fairkripke.hh~        |                                                  |
| ~kripke/kripkeexplicit.hh~         | ~spot/kripke/kripkegraph.hh~       | new implementation                               |
| ~kripke/kripke.hh~                 | ~spot/kripke/kripke.hh~            |                                                  |
| ~kripke/kripkeprint.hh~            | ~spot/twaalgos/hoa.hh~             | adhoc output format replaced by HOA              |
| ~kripkeparse/public.hh~            | ~spot/parseaut/public.hh~          | single parser for all automata                   |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~ltlast/allnodes.hh~               | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/atomic_prop.hh~            | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/automatop.hh~              | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/binop.hh~                  | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/bunop.hh~                  | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/constant.hh~               | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/formula.hh~                | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/multop.hh~                 | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/nfa.hh~                    |                                    | not supported anymore                            |
| ~ltlast/predecl.hh~                |                                    | not needed anymore                               |
| ~ltlast/refformula.hh~             |                                    | not needed anymore                               |
| ~ltlast/unop.hh~                   | ~spot/tl/formula.hh~               | new implementation of formulas                   |
| ~ltlast/visitor.hh~                |                                    | not supported anymore                            |
| ~ltlenv/declenv.hh~                | ~spot/tl/declenv.hh~               |                                                  |
| ~ltlenv/defaultenv.hh~             | ~spot/tl/defaultenv.hh~            |                                                  |
| ~ltlenv/environment.hh~            | ~spot/tl/environment.hh~           |                                                  |
| ~ltlparse/ltlfile.hh~              |                                    | not supported anymore                            |
| ~ltlparse/public.hh~               | ~spot/tl/parse.hh~                 |                                                  |
| ~ltlvisit/apcollect.hh~            | ~spot/tl/apcollect.hh~             |                                                  |
| ~ltlvisit/clone.hh~                |                                    | not needed anymore                               |
| ~ltlvisit/contain.hh~              | ~spot/tl/contain.hh~               |                                                  |
| ~ltlvisit/destroy.hh~              |                                    | not needed anymore                               |
| ~ltlvisit/dotty.hh~                | ~spot/tl/dot.hh~                   |                                                  |
| ~ltlvisit/dump.hh~                 | ~spot/tl/formula.hh~               | member of the formula class                      |
| ~ltlvisit/lbt.hh~                  | ~spot/tl/print.hh~                 |                                                  |
| ~ltlvisit/length.hh~               | ~spot/tl/length.hh~                |                                                  |
| ~ltlvisit/lunabbrev.hh~            | ~spot/tl/unabbrev.hh~              | generalized                                      |
| ~ltlvisit/nenoform.hh~             | ~spot/tl/nenoform.hh~              |                                                  |
| ~ltlvisit/postfix.hh~              |                                    | not supported anymore                            |
| ~ltlvisit/randomltl.hh~            | ~spot/tl/randomltl.hh~             |                                                  |
| ~ltlvisit/reduce.hh~               | ~spot/tl/simplify.hh~              | was already deprecated                           |
| ~ltlvisit/relabel.hh~              | ~spot/tl/relabel.hh~               |                                                  |
| ~ltlvisit/remove_x.hh~             | ~spot/tl/remove_x.hh~              |                                                  |
| ~ltlvisit/simpfg.hh~               | ~spot/tl/unabbrev.hh~              | generalized                                      |
| ~ltlvisit/simplify.hh~             | ~spot/tl/simplify.hh~              |                                                  |
| ~ltlvisit/snf.hh~                  | ~spot/tl/snf.hh~                   |                                                  |
| ~ltlvisit/tostring.hh~             | ~spot/tl/print.hh~                 |                                                  |
| ~ltlvisit/tunabbrev.hh~            | ~spot/tl/unabbrev.hh~              | generalized                                      |
| ~ltlvisit/wmunabbrev.hh~           | ~spot/lt/wmunabbrev.hh~            | generalized                                      |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~misc/bareword.hh~                 | ~spot/misc/bareword.hh~            |                                                  |
| ~misc/bddlt.hh~                    | ~spot/misc/bddlt.hh~               |                                                  |
| ~misc/bddop.hh~                    |                                    | not needed anymore                               |
| ~misc/bitvect.hh~                  | ~spot/misc/bitvect.hh~             |                                                  |
| ~misc/casts.hh~                    | ~spot/misc/casts.hh~               |                                                  |
| ~misc/common.hh~                   | ~spot/misc/common.hh~              |                                                  |
| ~misc/_config.h~                   | ~spot/misc/_config.h~              |                                                  |
| ~misc/escape.hh~                   | ~spot/misc/escape.hh~              |                                                  |
| ~misc/fixpool.hh~                  | ~spot/misc/fixpool.hh~             |                                                  |
| ~misc/formater.hh~                 | ~spot/misc/formater.hh~            |                                                  |
| ~misc/hashfunc.hh~                 | ~spot/misc/hashfunc.hh~            |                                                  |
| ~misc/hash.hh~                     | ~spot/misc/hash.hh~                |                                                  |
| ~misc/intvcmp2.hh~                 | ~spot/misc/intvcmp2.hh~            |                                                  |
| ~misc/intvcomp.hh~                 | ~spot/misc/intvcomp.hh~            |                                                  |
| ~misc/location.hh~                 | ~spot/misc/location.hh~            |                                                  |
| ~misc/ltstr.hh~                    | ~spot/misc/ltstr.hh~               |                                                  |
| ~misc/memusage.hh~                 | ~spot/misc/memusage.hh~            |                                                  |
| ~misc/minato.hh~                   | ~spot/misc/minato.hh~              |                                                  |
| ~misc/mspool.hh~                   | ~spot/misc/mspool.hh~              |                                                  |
| ~misc/optionmap.hh~                | ~spot/misc/optionmap.hh~           |                                                  |
| ~misc/position.hh~                 | ~spot/misc/position.hh~            |                                                  |
| ~misc/random.hh~                   | ~spot/misc/random.hh~              |                                                  |
| ~misc/satsolver.hh~                | ~spot/misc/satsolver.hh~           |                                                  |
| ~misc/timer.hh~                    | ~spot/misc/timer.hh~               |                                                  |
| ~misc/tmpfile.hh~                  | ~spot/misc/tmpfile.hh~             |                                                  |
| ~misc/unique_ptr.hh~               | ~memory~                           | use =std::unique_ptr= from C++11                 |
| ~misc/version.hh~                  | ~spot/misc/version.hh~             |                                                  |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~neverparse/public.hh~             | ~spot/parseaut/public.hh~          | single parser for all automata                   |
| ~sabaalgos/sabadotty.hh~           |                                    | not supported anymore                            |
| ~sabaalgos/sabareachiter.hh~       |                                    | not supported anymore                            |
| ~saba/explicitstateconjunction.hh~ |                                    | not supported anymore                            |
| ~saba/sabacomplementtgba.hh~       |                                    | not supported anymore                            |
| ~saba/saba.hh~                     |                                    | not supported anymore                            |
| ~saba/sabastate.hh~                |                                    | not supported anymore                            |
| ~saba/sabasucciter.hh~             |                                    | not supported anymore                            |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~taalgos/dotty.hh~                 | ~spot/taalgos/dot.hh~              |                                                  |
| ~taalgos/emptinessta.hh~           | ~spot/taalgos/emptinessta.hh~      |                                                  |
| ~taalgos/minimize.hh~              | ~spot/taalgos/minimize.hh~         |                                                  |
| ~taalgos/reachiter.hh~             | ~spot/taalgos/reachiter.hh~        |                                                  |
| ~taalgos/statessetbuilder.hh~      | ~spot/taalgos/statesetbuilder.hh~  |                                                  |
| ~taalgos/stats.hh~                 | ~spot/taalgos/stats.hh~            |                                                  |
| ~taalgos/tgba2ta.hh~               | ~spot/taalgos/tgba2ta.hh~          |                                                  |
| ~ta/taexplicit.hh~                 | ~spot/ta/taexplicit.hh~            | old implementation (ought to be changed)         |
| ~ta/ta.hh~                         | ~spot/ta/ta.hh~                    |                                                  |
| ~ta/taproduct.hh~                  | ~spot/ta/taproduct.hh~             |                                                  |
| ~ta/tgtaexplicit.hh~               | ~spot/ta/tgtaexplicit.hh~          | old implementation (ought to be changed)         |
| ~ta/tgta.hh~                       | ~spot/ta/tgta.hh~                  |                                                  |
| ~ta/tgtaproduct.hh~                | ~spot/ta/tgtaproduct.hh~           |                                                  |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~tgbaalgos/bfssteps.hh~            | ~spot/twaalgos/bfssteps.hh~        |                                                  |
| ~tgbaalgos/complete.hh~            | ~spot/twaalgos/complete.hh~        |                                                  |
| ~tgbaalgos/compsusp.hh~            | ~spot/twaalgos/compsusp.hh~        |                                                  |
| ~tgbaalgos/cutscc.hh~              |                                    | not supported anymore                            |
| ~tgbaalgos/cycles.hh~              | ~spot/twaalgos/cycles.hh~          |                                                  |
| ~tgbaalgos/degen.hh~               | ~spot/twaalgos/degen.hh~           |                                                  |
| ~tgbaalgos/dottydec.hh~            |                                    | not supported anymore                            |
| ~tgbaalgos/dotty.hh~               | ~spot/twaalgos/dot.hh~             |                                                  |
| ~tgbaalgos/dtbasat.hh~             | ~spot/twaalgos/dtbasat.hh~         |                                                  |
| ~tgbaalgos/dtgbacomp.hh~           | ~spot/twaalgos/complement.hh~      |                                                  |
| ~tgbaalgos/dtgbasat.hh~            | ~spot/twaalgos/dtwasat.hh~         |                                                  |
| ~tgbaalgos/dupexp.hh~              | ~spot/twaalgos/twagraph.hh~        | constructor of twa_graph                         |
| ~tgbaalgos/eltl2tgba_lacim.hh~     |                                    | not supported anymore                            |
| ~tgbaalgos/emptiness.hh~           | ~spot/twaalgos/emptiness.hh~       |                                                  |
| ~tgbaalgos/emptiness_stats.hh~     | ~spot/twaalgos/emptiness_stats.hh~ |                                                  |
| ~tgbaalgos/gtec/ce.hh~             | ~spot/twaalgos/gtec/ce.hh~         |                                                  |
| ~tgbaalgos/gtec/explscc.hh~        |                                    | not supported anymore                            |
| ~tgbaalgos/gtec/gtec.hh~           | ~spot/twaalgos/gtec/gtec.hh~       |                                                  |
| ~tgbaalgos/gtec/nsheap.hh~         |                                    | not supported anymore                            |
| ~tgbaalgos/gtec/sccstack.hh~       | ~spot/twaalgos/gtec/sccstack.hh~   |                                                  |
| ~tgbaalgos/gtec/status.hh~         | ~spot/twaalgos/gtec/status.hh~     |                                                  |
| ~tgbaalgos/gv04.hh~                | ~spot/twaalgos/gv04.hh~            |                                                  |
| ~tgbaalgos/hoaf.hh~                | ~spot/twaalgos/hoa.hh~             |                                                  |
| ~tgbaalgos/isdet.hh~               | ~spot/twaalgos/isdet.hh~           |                                                  |
| ~tgbaalgos/isweakscc.hh~           | ~spot/twaalgos/isweakscc.hh~       |                                                  |
| ~tgbaalgos/lbtt.hh~                | ~spot/twaalgos/lbtt.hh~            |                                                  |
| ~tgbaalgos/ltl2taa.hh~             | ~spot/twaalgos/ltl2taa.hh~         |                                                  |
| ~tgbaalgos/ltl2tgba_fm.hh~         | ~spot/twaalgos/ltl2tgba_fm.hh~     |                                                  |
| ~tgbaalgos/ltl2tgba_lacim.hh~      |                                    | not supported anymore                            |
| ~tgbaalgos/magic.hh~               | ~spot/twaalgos/magic.hh~           |                                                  |
| ~tgbaalgos/minimize.hh~            | ~spot/twaalgos/minimize.hh~        |                                                  |
| ~tgbaalgos/neverclaim.hh~          | ~spot/twaalgos/neverclaim.hh~      |                                                  |
| ~tgbaalgos/postproc.hh~            | ~spot/twaalgos/postproc.hh~        |                                                  |
| ~tgbaalgos/powerset.hh~            | ~spot/twaalgos/powerset.hh~        |                                                  |
| ~tgbaalgos/projrun.hh~             | ~spot/twaalgos/emptiness.hh~       | use =twa_run::project()= since Spot 2.1          |
| ~tgbaalgos/randomgraph.hh~         | ~spot/twaalgos/randomgraph.hh~     |                                                  |
| ~tgbaalgos/reachiter.hh~           | ~spot/twaalgos/reachiter.hh~       |                                                  |
| ~tgbaalgos/reducerun.hh~           | ~spot/twaalgos/emptiness.hh~       | now =twa_run::reduce()=                          |
| ~tgbaalgos/reductgba_sim.hh~       | ~spot/twaalgos/simulation.hh~      | was already deprecated                           |
| ~tgbaalgos/replayrun.hh~           | ~spot/twaalgos/emptiness.hh~       | now =twa_run::replay()=                          |
| ~tgbaalgos/rundotdec.hh~           | ~spot/twaalgos/emptiness.hh~       | now =twa_run::highlight()=                       |
| ~tgbaalgos/safety.hh~              | ~spot/twaalgos/strength.hh~        |                                                  |
| ~tgbaalgos/save.hh~                | ~spot/twaalgos/hoa.hh~             | adhoc output format replaced by HOA              |
| ~tgbaalgos/sccfilter.hh~           | ~spot/twaalgos/sccfilter.hh~       |                                                  |
| ~tgbaalgos/scc.hh~                 | ~spot/twaalgos/sccinfo.hh~         | new implementation restricted to ~twa_graph~     |
| ~tgbaalgos/se05.hh~                | ~spot/twaalgos/se05.hh~            |                                                  |
| ~tgbaalgos/simulation.hh~          | ~spot/twaalgos/simulation.hh~      |                                                  |
| ~tgbaalgos/stats.hh~               | ~spot/twaalgos/stats.hh~           |                                                  |
| ~tgbaalgos/stripacc.hh~            | ~spot/twaalgos/stripacc.hh~        |                                                  |
| ~tgbaalgos/tau03.hh~               | ~spot/twaalgos/tau03.hh~           |                                                  |
| ~tgbaalgos/tau03opt.hh~            | ~spot/twaalgos/tau03opt.hh~        |                                                  |
| ~tgbaalgos/translate.hh~           | ~spot/twaalgos/translate.hh~       |                                                  |
| ~tgbaalgos/word.hh~                | ~spot/twaalgos/word.hh~            |                                                  |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~tgba/bdddict.hh~                  | ~spot/twa/bdddict.hh~              |                                                  |
| ~tgba/bddprint.hh~                 | ~spot/twa/bddprint.hh~             |                                                  |
| ~tgba/formula2bdd.hh~              | ~spot/twa/formula2bdd.hh~          |                                                  |
| ~tgba/futurecondcol.hh~            |                                    | not supported anymore                            |
| ~tgba/public.hh~                   | ~spot/twa/twa.hh~                  |                                                  |
| ~tgba/sba.hh~                      |                                    | replaced by a flag in =twa=                      |
| ~tgba/statebdd.hh~                 |                                    | not supported anymore                            |
| ~tgba/state.hh~                    | ~spot/twa/twa.hh~                  |                                                  |
| ~tgba/succiterconcrete.hh~         |                                    | not supported anymore                            |
| ~tgba/succiter.hh~                 | ~spot/twa/twa.hh~                  |                                                  |
| ~tgba/taatgba.hh~                  | ~spot/twa/taatgba.hh~              |                                                  |
| ~tgba/tgbabddconcretefactory.hh~   |                                    | not supported anymore                            |
| ~tgba/tgbabddconcrete.hh~          |                                    | not supported anymore                            |
| ~tgba/tgbabddconcreteproduct.hh~   |                                    | not supported anymore                            |
| ~tgba/tgbabddcoredata.hh~          |                                    | not supported anymore                            |
| ~tgba/tgbabddfactory.hh~           |                                    | not supported anymore                            |
| ~tgba/tgbaexplicit.hh~             | ~spot/twa/twagraph.hh~             |                                                  |
| ~tgba/tgba.hh~                     | ~spot/twa/twa.hh~                  |                                                  |
| ~tgba/tgbakvcomplement.hh~         |                                    | use ~tgba_determinize()~ and ~dualize()~         |
| ~tgba/tgbamask.hh~                 | ~spot/twa/tgbamask.hh~             |                                                  |
| ~tgba/tgbaproduct.hh~              | ~spot/twa/tgbaproduct.hh~          |                                                  |
| ~tgba/tgbaproxy.hh~                |                                    | not supported anymore                            |
| ~tgba/tgbasafracomplement.hh~      | ~spot/twaalgos/determinize.hh~     |                                                  |
| ~tgba/tgbascc.hh~                  | ~spot/twaalgos/mask.hh~            |                                                  |
| ~tgba/tgbasgba.hh~                 | ~spot/twaalgos/sbacc.hh~           |                                                  |
| ~tgba/tgbatba.hh~                  | ~spot/twaalgos/degen.hh~           |                                                  |
| ~tgba/tgbaunion.hh~                |                                    | not yet reimplemented                            |
| ~tgba/wdbacomp.hh~                 | ~spot/twaalgos/dualize.hh~         | use ~dualize()~ instead                          |
|------------------------------------+------------------------------------+--------------------------------------------------|
| ~tgbaparse/public.hh~              | ~spot/parseaut/public.hh~          | single parser for all automata                   |

* BuDDy was renamed
  :PROPERTIES:
  :CUSTOM_ID: buddy
  :END:

Spot install a customized version of the BDD library BuDDy.

As shown in [[#includes][the table of renamed header files]], the header files for
this library were all renamed: they have an =x= appended (=bddx.h=,
=bvecx.h=, =fddx.h=).  The name of the library was renamed as well:
=libbdd.so= and =libbdd.a= are now respectively =libbddx.so= and
=libbddx.a=.  This means one should now pass =-lspot -lbddx= to the
linker (instead of =-lspot -lbdd=) when linking against Spot.

* New implementation for temporal logic formulas
  :PROPERTIES:
  :CUSTOM_ID: formulas
  :END:

As can be guessed from the [[#includes][the table of renamed header files]], the
class hierarchy for temporal formulas has been entirely
rewritten.  This change is actually quite massive (~13200 lines
removed, ~8200 lines added), and brings some nice benefits:
- LTL/PSL formulas are now represented by lightweight formula
  objects (instead of pointers to children of an abstract
  formula class) that perform reference counting automatically.
- There is no hierarchy anymore: all operators are represented by
  a single type of node in the syntax tree, and an enumerator is
  used to distinguish between operators.
- Visitors have been replaced by member functions such as =map()=
  or =traverse()=, that take a function (usually written as a
  lambda function) and apply it to the nodes of the tree.
- As a consequence, writing algorithms that manipulate formula is more
  friendly, and several algorithms that spanned a few pages have been
  reduced to a few lines.  [[file:tut03.org][This page]] illustrates the new interface.

Also the =spot::ltl= namespace has been removed: everything is
directly in =spot= now.

In code where formulas are just parsed from input string, and then
passed on to other algorithms (e.g., translation to automata): it will
suffice to change all occurrences of =const spot::ltl::formula*= into
a plain =spot::formula=, and remove all calls to =->destroy()= or
=->clone()= (that were used to perform explicit reference counting).

* Many objects are now returned as =std::shared_ptr=
  :PROPERTIES:
  :CUSTOM_ID: shared_ptr
  :END:

By convention =foo_ptr= is a =typedef= for =std::share_ptr<foo>=.  The
following typedefs are provided:

#+BEGIN_SRC sh :results verbatim :exports results
find ../../spot -name '[^.]*.hh' | xargs grep -h 'typedef.*_ptr;' | sed 's/^[ \t]*//' | sort -u
#+END_SRC

#+RESULTS:
#+begin_example
typedef std::shared_ptr<bdd_dict> bdd_dict_ptr;
typedef std::shared_ptr<const fair_kripke> const_fair_kripke_ptr;
typedef std::shared_ptr<const kripke> const_kripke_ptr;
typedef std::shared_ptr<const kripke_explicit> const_kripke_explicit_ptr;
typedef std::shared_ptr<const parsed_aut> const_parsed_aut_ptr;
typedef std::shared_ptr<const taa_tgba_formula> const_taa_tgba_formula_ptr;
typedef std::shared_ptr<const taa_tgba_string> const_taa_tgba_string_ptr;
typedef std::shared_ptr<const ta> const_ta_ptr;
typedef std::shared_ptr<const ta_explicit> const_ta_explicit_ptr;
typedef std::shared_ptr<const ta_product> const_ta_product_ptr;
typedef std::shared_ptr<const tgta> const_tgta_ptr;
typedef std::shared_ptr<const tgta_explicit> const_tgta_explicit_ptr;
typedef std::shared_ptr<const twa> const_twa_ptr;
typedef std::shared_ptr<const twa_graph> const_twa_graph_ptr;
typedef std::shared_ptr<const twa_product> const_twa_product_ptr;
typedef std::shared_ptr<const twa_run> const_twa_run_ptr;
typedef std::shared_ptr<emptiness_check> emptiness_check_ptr;
typedef std::shared_ptr<emptiness_check_result> emptiness_check_result_ptr;
typedef std::shared_ptr<fair_kripke> fair_kripke_ptr;
typedef std::shared_ptr<kripke_explicit> kripke_explicit_ptr;
typedef std::shared_ptr<kripke_graph> kripke_graph_ptr;
typedef std::shared_ptr<kripke> kripke_ptr;
typedef std::shared_ptr<parsed_aut> parsed_aut_ptr;
typedef std::shared_ptr<taa_tgba_formula> taa_tgba_formula_ptr;
typedef std::shared_ptr<taa_tgba_string> taa_tgba_string_ptr;
typedef std::shared_ptr<ta_explicit> ta_explicit_ptr;
typedef std::shared_ptr<ta_product> ta_product_ptr;
typedef std::shared_ptr<ta> ta_ptr;
typedef std::shared_ptr<tgta_explicit> tgta_explicit_ptr;
typedef std::shared_ptr<tgta> tgta_ptr;
typedef std::shared_ptr<twa_graph> twa_graph_ptr;
typedef std::shared_ptr<twa_product> twa_product_ptr;
typedef std::shared_ptr<twa_run> twa_run_ptr;
typedef std::shared_ptr<twa> twa_ptr;
#+end_example

You should update any =foo*= to =foo_ptr= if it appears in this list,
and remove any explicit call to =delete=.  Additionally, if =foo= is a
class, there is usually a =make_foo(...)= function that calls
=std::make_shared<foo>(...)=.

As an example of usage, see [[file:tut22.org::#cpp][this example of creating an automaton
explicitly]] where =spot::make_bdd_dict()= is used to create a BDD
dictionary that is then passed to =spot::make_twa_graph()=.

* The =twa= class replaces =tgba=
  :PROPERTIES:
  :CUSTOM_ID: tgba-twa
  :END:

The change has several implications besides just the changing the
name:

- =twa= can represent a larger class of automata than =tgba= could,
  since [[file:concepts.org::#acceptance-condition][the acceptance condition can be arbitrarily complex]].
  Algorithm that used to input =tgba= can be either generalized to
  handle those larger acceptance conditions, or restricted to
  generalized Büchi acceptance.   The typical way to ensure
  that an =input= automaton has generalized Büchi acceptance is
#+BEGIN_SRC C++
     if (!input->acc().is_generalized_buchi())
        throw std::runtime_error
          ("myalgorithm() can only works with generalized Büchi acceptance");
#+END_SRC

- Some methods of the =tgba= class have been removed, include some
  pure virtual methods. If you wrote a subclass, you may simply remove
  the following methods:
  - =compute_support_conditions()=,
  - =compute_support_variables()=,
  - =transition_annotation()=,
  - =neg_acceptance_conditions()=.

- The =succ_iter()= method lost its last two (optional) arguments.

- The badly named =number_of_acceptance_conditions()= has been renamed
  to =num_sets()=.

- The =tgba_succ_iterator= class was renamed to =twa_succ_iterator=, and
  its interface was changed:
  - =current_state()=, =current_condition()=, and
    =current_acceptance_conditions()= are now named respectively
    =dst()=, =cond()=, =acc()=.
  - the =first()= and =next()= method now return a Boolean that
    indicates whether we moved to a new successor (=true=), or reached
    the end of the list of successors (=false=).  This return value
    should be the same as what =!done()= would return, and can be used
    to avoid some costly calls to the =done()= virtual function.

- Membership to acceptance sets is now represented using a bit set
  (instead of BDDs).  An T\omega{}A =aut= uses =aut->num_sets()=
  acceptance sets numbered from =0= to =aut->num_sets()-1=.  The bit
  sets are implemented as instances of =spot::acc_cond::mark_t=, so
  they are also called "acceptance marks".

- The =twa::release_iter()= method allow iterators to be recycled.
  Each =twa= now contains a mutable field =iter_cache_= where
  =release_iter()= stores the last returned iterator.  If this field
  is not equal to =nullptr=, then =succ_iter()= can use it to allocate
  a new iterator more efficiently.

  In the code for =succ_iter()=, instead of:
  #+BEGIN_SRC C++
      // ...
      return new my_iterator(arg1, arg2, arg3);
  #+END_SRC
  we can now have
  #+BEGIN_SRC C++
      // ...
      if (iter_cache_)
	{
	   my_iterator* it = static_cast<my_iterator*>(iter_cache_);
	   iter_cache_ = nullptr;
	   // Some method to change the member that need changing.
	   // (Here we assume that arg2 is the same for all iterators
	   // built on this automaton.)
	   it->recycle(arg1, arg3);
	   return it;
	}
      return new my_iterator(arg1, arg2, arg3);
  #+END_SRC

  So not only do we save the calls to =new= and =delete=, but we also
  save the time it takes to construct the objects (including setting
  up the virtual table), and via a =recycle()= method that has to be
  added to the iterator, we update only the attributes that needs to
  be updated (for instance if the iterator contains a pointer back to
  the automaton, this pointer requires no update when the iterator is
  recycled).

  #+BEGIN_caveat
    The iterator stored in =twa::iter_cache_= is destroyed by
    =twa::~twa()=.  In some case, this is too late.  For instance the
    class =twa_product= uses a custom memory pool to allocate new
    iterators more efficiently, and this memory pool is destroyed in
    =twa_product::~twa_product()=.  In this case, referencing
    =twa::iter_cache_= for its deletion in =twa::~tgba()= would be
    incorrect: it has to be done in =twa_product::~twa_product()=
    before destroying the pool.
  #+END_caveat


For a TGBA =aut=, and a state =s=, the original way to loop over the
successors of =s= was:
#+BEGIN_SRC C++
  tgba_succ_iterator* i = aut->succ_iter(s);
  for (i->first(); !i->done(); i->next())
    {
       // use i->current_state()
       //     i->current_condition()
       //     i->current_acceptance_conditions()
    }
  delete i;
#+END_SRC

While the above would still run after a few renamings, it can now be
written more efficiently as:

#+BEGIN_SRC C++
  twa_succ_iterator* i = aut->succ_iter(s);
  if (i->first())
    do
      {
        // use i->dst()
        //     i->cond()
        //     i->acc()
      }
    while (i->next());
  aut->release_iter(i);
#+END_SRC

If the original code did $1$ virtual call to =first()=, $n+1$ virtual
calls to =done()=, and $n$ virtual calls to =next()=, the new version
does as many calls to =first()= and =done()= while avoiding all the
calls to =done()=.  Furthermore the call =release_iter()= makes it
possible for the next call to =succ_iter()= to reuse the same
iterator.

Because the the above loop is quite common we also have some syntactic
sugar via the new =succ()= method that returns a fake container with
=begin()= and =end()= methods so that this works:

#+BEGIN_SRC C++
for (auto i: aut->succ(s))
  {
    // use i->dst()
    //     i->cond()
    //     i->acc()
  }
#+END_SRC

- Each =twa= now has a BDD dictionary, so the =get_dict()= method is
  implemented once for all in =twa=, and should not be implemented
  anymore in sub-classes.

- There should now be very few cases where it is necessary to call
  methods of the BDD dictionary attached to a =twa=.  Registering
  the atomic proposition used by a =twa= should now be done via the
  =twa::register_ap()= or =twa::copy_ap_of()= methods.  Accessing
  all registered propositions is achievable with =twa::ap()= or
  =twa::ap_vars()=.  All propositions registered by an automaton are
  automatically unregistered when the automaton is destroyed.


* Various renamings
  :PROPERTIES:
  :CUSTOM_ID: renamings
  :END:

  The following is a non-exhaustive list of functions or classes that
  have been renamed.

| old name                                                    | new name                                    | comment                                                   |
|-------------------------------------------------------------+---------------------------------------------+-----------------------------------------------------------|
| ~dstar_parse()~                                             | ~parse_aut()~                               | single parser for all automata                            |
| ~dtgba_complement()~                                        | ~dualize()~                                 |                                                           |
| ~dupexp_bfs()~                                              |                                             | deleted                                                   |
| ~dupexp_dfs()~                                              | ~make_twa_graph()~                          |                                                           |
| ~format_parse_aut_errors()~                                 | ~parsed_aut::format_errors()~               |                                                           |
| ~emptiness_check_instantiator::construct()~                 | ~make_emptiness_check_instantiator()~       |                                                           |
| ~emptiness_check_instantiator::max_acceptance_conditions()~ | ~emptiness_check_instantiator::max_sets()~  |                                                           |
| ~emptiness_check_instantiator::min_acceptance_conditions()~ | ~emptiness_check_instantiator::min_sets()~  |                                                           |
| ~hoaf_reachable()~                                          | ~print_hoa()~                               |                                                           |
| ~is_guarantee_automaton()~                                  | ~is_terminal_automaton()~                   |                                                           |
| ~kripke_parse()~                                            | ~parse_aut()~                               | single parser for all automata                            |
| ~kripke_save_reachable()~                                   | ~print_hoa()~                               | adhoc output format replaced by HOA                       |
| ~kripke_save_reachable_renumbered()~                        | ~print_hoa()~                               | adhoc output format replaced by HOA                       |
| ~lbtt_parse()~                                              | ~parse_aut()~                               | single parser for all automata                            |
| ~lbtt_reachable()~                                          | ~print_lbtt()~                              |                                                           |
| ~ltl::formula::is_X_free()~                                 | ~formula::is_syntactic_stutter_invariant()~ |                                                           |
| ~ltl::ltl_simplifier~                                       | ~tl_simplifier~                             |                                                           |
| ~ltl::parse_boolean()~                                      | ~parse_infix_boolean()~                     |                                                           |
| ~ltl::parse_lbt()~                                          | ~parse_prefix_ltl()~                        |                                                           |
| ~ltl::parse()~                                              | ~parse_infix_psl()~                         |                                                           |
| ~ltl::parse_sere()~                                         | ~parse_infix_sere()~                        |                                                           |
| ~ltl::to_latex_string()~                                    | ~print_latex_psl()~                         | also ~str_latex_psl()~                                    |
| ~ltl::to_lbt_string()~                                      | ~print_lbt_ltl()~                           | also ~str_lbt_ltl()~                                      |
| ~ltl::to_sclatex_string()~                                  | ~print_sclatex_psl()~                       | also ~str_sclatex_psl()~                                  |
| ~ltl::to_spin_string()~                                     | ~print_spin_ltl()~                          | also ~str_spin_ltl()~                                     |
| ~ltl::to_string()~                                          | ~print_psl()~, ~print_sere()~               | also ~str_psl()~ or ~str_sere()~                          |
| ~ltl::to_ut8_string()~                                      | ~print_utg8_psl()~, ~print_utf8_sere()~     | also ~str_utf8_psl()~ or ~str_utf8_sere()~                |
| ~ltl::to_wring_string()~                                    | ~print_wring_ltl()~                         | also ~str_wring_ltl()~                                    |
| ~neverclaim_parse()~                                        | ~parse_aut()~                               | single parser for all automata                            |
| ~never_claim_reachable()~                                   | ~print_never_claim()~                       |                                                           |
| ~print_tgba_run()~                                          | ~tgba_run::operator<<()~                    |                                                           |
| ~reduce_run()~                                              | ~twa_run::reduce()~                         |                                                           |
| ~replay_tgba_run()~                                         | ~twa_run::replay()~                         |                                                           |
| ~scc_map~                                                   | ~scc_info~                                  | new implementation restricted to ~twa_graph~              |
| ~ta_succ_iterator::current_acceptance_conditions()~         | ~ta_succ_iterator::acc()~                   |                                                           |
| ~ta_succ_iterator::current_condition()~                     | ~ta_succ_iterator::cond()~                  |                                                           |
| ~ta_succ_iterator::current_state()~                         | ~ta_succ_iterator::dst()~                   |                                                           |
| ~tgba~                                                      | ~twa~                                       |                                                           |
| ~tgba::all_acceptance_conditions()~                         |                                             | use ~tgba::acc().accepting()~ or ~tgba::acc().all_sets()~ |
| ~tgba::neg_acceptance_conditions()~                         |                                             | deleted                                                   |
| ~tgba::number_of_acceptance_conditions()~                   | ~tgba::num_sets()~                          |                                                           |
| ~tgba::support_conditions()~                                |                                             | deleted                                                   |
| ~tgba::support_variables()~                                 |                                             | deleted                                                   |
| ~tgba_explicit_formula~                                     |                                             | deleted                                                   |
| ~tgba_explicit_number~                                      | ~twa_graph~                                 | new implementation                                        |
| ~tgba_explicit_string~                                      |                                             | deleted                                                   |
| ~tgba_parse()~                                              | ~parse_aut()~                               | single parser for all automata                            |
| ~tgba_reachable_iterator~                                   | ~twa_reachable_iterator~                    |                                                           |
| ~tgba_reachable_iterator_breadth_first~                     | ~twa_reachable_iterator_breadth_first~      |                                                           |
| ~tgba_reachable_iterator_depth_first~                       | ~twa_reachable_iterator_depth_first~        |                                                           |
| ~tgba_run_to_tgba()~                                        | ~twa_run::as_twa()~                         |                                                           |
| ~tgba_run~                                                  | ~twa_run~                                   |                                                           |
| ~tgba_save_reachable()~                                     | ~print_hoa()~                               | adhoc output format replaced by HOA                       |
| ~tgba_statistics::transitions()~                            | ~twa_statistics::edges()~                   |                                                           |
| ~tgba_sub_statistics::sub_transitions()~                    | ~twa_sub_statistics::transitions()~         |                                                           |
| ~tgba_succ_iterator::current_acceptance_conditions()~       | ~twa_succ_iterator::acc()~                  |                                                           |
| ~tgba_succ_iterator::current_condition()~                   | ~twa_succ_iterator::cond()~                 |                                                           |
| ~tgba_succ_iterator::current_state()~                       | ~twa_succ_iterator::dst()~                  |                                                           |

#  LocalWords:  utf html cpp BuDDy ptr TGBA tgba twa tgba renamings
#  LocalWords:  reimplemented cpp SRC bdd bddx BuDDy bvec bvecx fdd
#  LocalWords:  fddx dstarparse eltlparse iface kripke adhoc ltlast
#  LocalWords:  kripkeparse ltlenv ltlparse ltlvisit config sabaalgos
#  LocalWords:  neverparse saba taalgos tgbaalgos dualize tgbaparse
#  LocalWords:  libbdd libbddx lspot lbddx lbdd namespace ptr xargs
#  LocalWords:  typedefs sed aut taa tgta acc buchi myalgorithm succ
#  LocalWords:  iter num dst cond BDDs arg dstar dtgba dupexp bfs dfs
#  LocalWords:  instantiator hoaf lbtt tl simplifier boolean psl str
#  LocalWords:  lbt sclatex utg utf neverclaim scc
