fasb

Implementation of the faceted answer set browser, introduced in https://doi.org/10.1609/aaai.v36i5.20506.

fasb is a REPL system implemented on top of the clingo solver. It enables answer set navigation alongside quantitative reasoning.

quickstart

fasb as a REPL:

$ fasb program.lp 0
fasb v0.1.0
42930d520670354cfb84ded47e54142559c70e8cd6b36d6eb2b1a24433adc78f
:: ! 2         -- enumerate up to 2 answer sets
solution 1:
a e
solution 2:
b d e
found 2
:: ?           -- query facets
b d c a
:: #!!         -- query weights based on answer set counting
0.3333 2 b     -- [reduces # by] [remaining #] [facet]
0.6667 1 d
0.3333 2 ~d
0.6667 1 c
0.3333 2 ~c
0.6667 1 a
0.3333 2 ~a
:: ' max#f     -- use facet-counting strictly goal-oriented mode 
:: $$          -- perform step (causing highest uncertainty reduction)
1.0000 0 d     -- activated facet `d` (reduced facet count by 100%)
:: @           -- query current route
d
:: !           -- enumerate all answer sets under current route
solution 1:
b d e
found 1
:: --          -- clear route
:: #!          -- query answer set count
3
:: L+ {p;q;r}. -- add rule
:: L
a;b.
c;d :- b.
e.

{p;q;r}.
:: A           -- display atoms  
a c d p q b e r
:: ?           -- display facets
b q a c p r d
:: #!
24
:: #??         -- query weights based on facet counting
0.2857 10 b
0.5714 6 ~b
0.1429 12 q
0.1429 12 ~q
0.5714 6 a
0.2857 10 ~a
0.1429 12 p
0.1429 12 ~p
0.5714 6 d
0.1429 12 ~d
0.5714 6 c
0.1429 12 ~c
0.1429 12 r
0.1429 12 ~r

fasb as an interpreter:

$ cat script.fsb
! 1                  -- output 1 answer set
#?                   -- query facet count        
\ != #f 0 | $$ . ! 2 -- while condition | command . command
@                    -- display route                  
$ fasb program.lp 0 srcipt.fsb
fasb v0.1.0
42930d520670354cfb84ded47e54142559c70e8cd6b36d6eb2b1a24433adc78f
:: ! 1
solution 1:
a e
found 1
:: #?
8
:: \ != #f 0 | $$ . ! 2
_ _ b
solution 1:
b d e
solution 2:
b c e
found 2
_ _ c
solution 1:
b c e
found 1
:: @
b c

install

1. install cargo
2. cargo install fasb

build

1. install cargo
2. cd fasb && cargo build -r

usage

fasb program [clingo flags] [script]

Apart from being a REPL system, fasb can also be used as an interpreter of instructions, which will be performed line by line. To use fasb as an interpreter add the feature flag --feature interpreter when installing or building. When using the interpreter, provide a script.

The designated syntax for regular expressions (regex) can be found here.

commands

• \ condition | instructions ... loop '.' seperated instructions while condition={!=,<,<=,>,>=}\s^\d+$\s{#a,#f,#r} where
  • #a ... answer set count
  • #f ... facet count
  • #r ... size of current route
• + args ... activate args=[whitespace seperated facets]
  • facet=[p|~p]
  • e.g.: activate +a and -b: + a ~b
• - ... deactivate previously activated facet
• -- ... deactivate all facets
• ? regex ... display current facets matching regex
• @ ... query current route
• ' arg ... select navigation mode arg=[{min,max}#{a,f}|go]
  • by default goal-oriented (go)
  • min* ... explore
  • max* ... strictly goal-oriented
  • *#a ... answer set counting
  • *#f ... facet counting
• $ regex ... query proposed next step in selected mode among facets matching regex
• #? ... query facet count
• #! ... query answer set count
• $$ regex ... perform next step in selected mode among facets matching regex
• #?? regex ... query facet counts (weights) under each facets matching regex
• #!! regex ... query answer set counts (weights) under each facets matching regex
• L+ rule ... add rule (no whitespaces in rule permitted)
• L- rule ... remove rule
• L ... display underlying program
• A ... display atoms (herbrand base)
• AA atom ... check whether atom belongs to herbrand base
• man ... display brief manual
• :q ... exit fasb