boolean expression manipulator for educational purposes
boolexman is a boolean expression manipulator (program) to aid teaching or studying propositional logic, primarily aimed for the Informatics 1 - Computation and Logic at The University of Edinburgh School of Informatics.
boolexman offers various commands for working with boolean expressions, from those that can transform any given expression into Disjunctive Normal Form (i.e. an OR of ANDs) or Conjunctive Normal Form (i.e. an AND of ORs), to those (functions) for fully-automated resolution, entailment, and partial-evaluation. All commands shows their working step-by-step, with detailed explanations of each rule that was used.
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Clone the repository
$ git clone https://github.com/boramalper/boolexman $ cd boolexman -
Update the
cabalpackage cache$ cabal update -
Install the dependencies of boolexman:
$ cabal install --only-dependencies --enable-tests -
Test if boolexman works:
$ cabal run -
(Optional) Install it to your system:
$ cabal install- If you wish not to install, you can always navigate to the directory you
cloned boolexman to, and execute
cabal run.
- If you wish not to install, you can always navigate to the directory you
cloned boolexman to, and execute
Navigate to the directory you cloned boolexman to, and execute cabal test.
Beware that some of the tests might (very likely indeed) timeout -due to some performance problems I intend to address in an unforeseeable future- none of the tests should fail.
If you intend to contribute to boolexman, contact me at [email protected].
boolexman can be transmogrified into JavaScript, which in turn allows it to be used as a Web application in browser, all thanks to GHCJS. Although it might not be as reliable as the traditional method, it also makes boolexman significantly more affordable.
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Install AND setup GHCJS, and all of its requirements by following the documentation:
https://github.com/ghcjs/ghcjs
- Booting (i.e.
ghcjs-boot) might take a while, be patient.
- Booting (i.e.
-
Enter the
src/directory:cd src/ -
Transmogrify boolexman:
ghcjs -main-is WebMain --make WebMain.hs -o boolexman -
Copy the JavaScript files:
cp boolexman.jsexe/lib.js boolexman.jsexe/out.js boolexman.jsexe/rts.js boolexman.jsexe/runmain.js ../web/ -
(Optional) Get rid of the
.js_hiand.js_ofiles:rm -r *.js* Engine/*.js*
Each time you run boolexman, you will be greeted with a screen like follows:
boolexman - boolean expression manipulator | v0.2.0.0
1>
1> is called the prompt, and it indicates that boolexman is ready to
accept your command. The number before the greater-than symbol shows the
command number, which is provided only as a convenience to the user and has no
importance to the program at all. boolexman uses Haskeline library to
provide a GNU Readline-like rich line-editing functionality to its users,
including moving backwards/forwards in the command history to Emacs/vi specific
key bindings, whose full list can be found on
Haskeline Wiki.
Every command consists of a verb (i.e. command verb), and arguments of some
format, which depends on the verb but is consistent throughout the
boolexman. Whilst any errors are printed on the prompt screen, the output of
the commands are piped to the less, which allows you to scroll in all four
directions (which is a crucial functionality since some commands produce large
outputs [i.e. entailment trees]). You can also save the output of your
commands to the disk, which are explained below.
Every command to the boolexman must start with a command verb, followed by zero or more space-separated arguments. Every command verb starts with a letter, followed by optionally some more alphanumeric characters. Command verbs are case-insensitive!
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quitQuits the program. Takes no arguments.
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symbolsexpression :: ExpressionExtracts all the symbols of
expression.Example:
1> symbols (if A iff not B then C implies D xor E else True and F or not D)1 symbols ((A <=> !B) ? (C => (D + E)) : ((True ^ F) v !D)) 2 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 3 4 • A 5 • B 6 • C 7 • D 8 • E 9 • F -
subexpressionsexpression :: ExpressionFinds all the subexpressions of
expression, including theexpressionitself.Example:
1> subexpressions (if A iff not B then C implies D xor E else True and F or not D)1 subexpressions ((A <=> !B) ? (C => (D + E)) : ((True ^ F) v !D)) 2 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 3 4 Sub-Expression Tree: 5 ((A <=> !B) ? (C => (D + E)) : ((True ^ F) v !D)) 6 ├─ (A <=> !B) 7 │ ├─ A 8 │ ├─ !B 9 │ │ ├─ B 10 ├─ (C => (D + E)) 11 │ ├─ C 12 │ ├─ (D + E) 13 │ │ ├─ D 14 │ │ ├─ E 15 ├─ ((True ^ F) v !D) 16 │ ├─ (True ^ F) 17 │ │ ├─ True 18 │ │ ├─ F 19 │ ├─ !D 20 │ │ ├─ D 21 22 Sub-Expression List: 23 • True 24 • A 25 • B 26 • C 27 • D 28 • E 29 • F 30 • !B 31 • !D 32 • (D + E) 33 • (True ^ F) 34 • (A <=> !B) 35 • (C => (D + E)) 36 • ((True ^ F) v !D) 37 • ((A <=> !B) ? (C => (D + E)) : ((True ^ F) v !D)) -
tabulateexpression :: ExpressionConstructs a truth table with subexpressions as columns, and possible evaluations as rows of the truth table.
Example:
1> tabulate (C implies D xor E <=> True and F or not D)1 tabulate ((C => (D + E)) <=> ((True ^ F) v !D)) 2 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 3 4 ╔════╤═╤═╤═╤═╤══╤═══════╤══════════╤══════════════╤═════════════════╤══════════════════════════════════════╗ 5 ║True│C│D│E│F│!D│(D + E)│(True ^ F)│(C => (D + E))│((True ^ F) v !D)│((C => (D + E)) <=> ((True ^ F) v !D))║ 6 ╟────┼─┼─┼─┼─┼──┼───────┼──────────┼──────────────┼─────────────────┼──────────────────────────────────────╢ 7 ║ T │F│F│F│F│T │ F │ F │ T │ T │ T ║ 8 ║ T │F│F│F│T│T │ F │ T │ T │ T │ T ║ 9 ║ T │F│F│T│F│T │ T │ F │ T │ T │ T ║ 10 ║ T │F│F│T│T│T │ T │ T │ T │ T │ T ║ 11 ║ T │F│T│F│F│F │ T │ F │ T │ F │ F ║ 12 ║ T │F│T│F│T│F │ T │ T │ T │ T │ T ║ 13 ║ T │F│T│T│F│F │ F │ F │ T │ F │ F ║ 14 ║ T │F│T│T│T│F │ F │ T │ T │ T │ T ║ 15 ║ T │T│F│F│F│T │ F │ F │ F │ T │ F ║ 16 ║ T │T│F│F│T│T │ F │ T │ F │ T │ F ║ 17 ║ T │T│F│T│F│T │ T │ F │ T │ T │ T ║ 18 ║ T │T│F│T│T│T │ T │ T │ T │ T │ T ║ 19 ║ T │T│T│F│F│F │ T │ F │ T │ F │ F ║ 20 ║ T │T│T│F│T│F │ T │ T │ T │ T │ T ║ 21 ║ T │T│T│T│F│F │ F │ F │ F │ F │ T ║ 22 ║ T │T│T│T│T│F │ F │ T │ F │ T │ F ║ 23 ╚════╧═╧═╧═╧═╧══╧═══════╧══════════╧══════════════╧═════════════════╧══════════════════════════════════════╝ -
evalsymbols that are true :: List of Symbolssymbols that are false :: List of Symbolsexpression :: ExpressionEvaluates the
expressiongiven a set ofsymbols that are trueandsymbols that are false. If not every symbol in theexpressionappears in at least one of the sets, then theexpressionwill be partially evaluated and the result will be in terms of those symbols that do not exists in neither set, in Disjunctive Normal Form.If some symbols that do not appear in the
expressionappear in one of the list of symbols, boolexman will display a warning at the top of its output, but otherwise will work as intended.If some symbols appear in both lists of symbols, then boolexman will display an error.
Example:
1> eval [A, D] [E,Z] (if A iff not B then C implies D xor E else True and F or not D)1 eval [A,D] [E,Z] ((A <=> !B) ? (C => (D + E)) : ((True ^ F) v !D)) 2 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 3 4 WARNING: Some of the true/false symbols have not been found in the expression! 5 6 Redundant False Symbols: [Z] 7 8 1. Transform into Conjunctive Normal Form: 9 • {F, !D, !A, !B} 10 • {F, !D, B, A} 11 • {A, !B, !C, D, E} 12 • {A, !B, !C, !D, !E} 13 • {!A, B, !C, D, E} 14 • {!A, B, !C, !D, !E} 15 • {F, !D, !C, !E} 16 17 2. Eliminate all maxterms which constains a true symbol: 18 • {F, !D, B, A} 19 is eliminated because A is true. 20 • {A, !B, !C, D, E} 21 is eliminated because A is true. 22 • {A, !B, !C, !D, !E} 23 is eliminated because A is true. 24 • {!A, B, !C, D, E} 25 is eliminated because D is true. 26 • {!A, B, !C, !D, !E} 27 is eliminated because !E is true. 28 • {F, !D, !C, !E} 29 is eliminated because !E is true. 30 31 Remaining maxterms: 32 • {F, !D, !A, !B} 33 34 3. Transform into Disjunctive Normal Form: 35 • {F, !D, !A, !B} 36 37 4. Eliminate all minterms which constains a false symbol: 38 • {F, !D, !A, !B} 39 is eliminated because !A is false. 40 41 Remaining minterms: 42 • {False} 43 44 Resultant expression: 45 False -
toCNF/toDNFexpression :: ExpressionTranforms the
expressioninto Disjunctive/Conjunctive Normal Form.Example:
1> toCNF (if A iff not B then C implies D else True and F or not D)1 toCNF ((A <=> !B) ? (C => D) : ((True ^ F) v !D)) 2 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 3 4 1. Transform all if-then-else (ITE) expressions: 5 • ((A <=> !B) ? (C => D) : (F v !D)) 6 is transformed into 7 (((A <=> !B) ^ (C => D)) v (!(A <=> !B) ^ (F v !D))) 8 9 After all ITE expressions are transformed: 10 (((A <=> !B) ^ (C => D)) v (!(A <=> !B) ^ (F v !D))) 11 12 2. Transform all if-and-only-if (IFF) expressions: 13 • (A <=> !B) 14 is transformed into 15 !(A + !B) 16 17 After all IFF expressions are transformed: 18 ((!(A + !B) ^ (C => D)) v (!!(A + !B) ^ (F v !D))) 19 20 3. Tranform all implications: 21 • (C => D) 22 is transformed into 23 (!C v D) 24 25 After all implications are transformed: 26 ((!(A + !B) ^ (!C v D)) v (!!(A + !B) ^ (F v !D))) 27 28 4. Tranform all exclusive-or (XOR) expressions: 29 • (A + !B) 30 is transformed into 31 ((A v !B) ^ (!A v !!B)) 32 33 After all XOR expressions are transformed: 34 ((!((A v !B) ^ (!A v !!B)) ^ (!C v D)) v (!!((A v !B) ^ (!A v !!B)) ^ (F v !D))) 35 36 5. Distribute NOTs: 37 • !!B 38 is transformed into 39 B 40 • !((A v !B) ^ (!A v B)) 41 is transformed into 42 (!(A v !B) v !(!A v B)) 43 • !(A v !B) 44 is transformed into 45 (!A ^ !!B) 46 • !(!A v B) 47 is transformed into 48 (!!A ^ !B) 49 • !!A 50 is transformed into 51 A 52 • !((!A ^ B) v (A ^ !B)) 53 is transformed into 54 (!(!A ^ B) ^ !(A ^ !B)) 55 • !(!A ^ B) 56 is transformed into 57 (!!A v !B) 58 • !(A ^ !B) 59 is transformed into 60 (!A v !!B) 61 62 After all NOTs are distributed: 63 ((((!A ^ B) v (A ^ !B)) ^ (!C v D)) v ((A v !B) ^ (!A v B) ^ (F v !D))) 64 65 6. Distribute ORs over ANDs: 66 • ((!A ^ B) v (A ^ !B)) 67 is transformed into 68 ((!A v !B) ^ (B v A)) 69 • (((!A v !B) ^ (B v A) ^ (!C v D)) v ((A v !B) ^ (!A v B) ^ (F v !D))) 70 is transformed into 71 ((((!A v !B) ^ (B v A)) v A v !B) ^ (((!A v !B) ^ (B v A)) v !A v B) ^ (((!A v !B) ^ (B v A)) v F v !D) ^ (!C v D v A v !B) ^ (!C v D v !A v B)) 72 • (((!A v !B) ^ (B v A)) v A v !B) 73 is transformed into 74 True 75 • (((!A v !B) ^ (B v A)) v !A v B) 76 is transformed into 77 True 78 • (((!A v !B) ^ (B v A)) v F v !D) 79 is transformed into 80 ((F v !D v !A v !B) ^ (F v !D v B v A)) 81 82 Resultant expression: 83 ((F v !D v !A v !B) ^ (F v !D v B v A) ^ (!C v D v A v !B) ^ (!C v D v !A v B)) -
resolveexpression :: ExpressionIteratively applies the resolution rule to automatically resolve an expression until either an empty clause is found or there are no more symbols to resolve on left.
Example:
1> resolve (if A iff not B then C implies D xor E else True and F or not D)1 resolve ((A <=> !B) ? (C => (D + E)) : ((True ^ F) v !D)) 2 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 3 4 • B[F,!D,!A,!B] 5 • B[F,!D,B,A] 6 • B[A,!B,!C,D,E] 7 • B[A,!B,!C,!D,!E] 8 • B[!A,B,!C,D,E] 9 • B[!A,B,!C,!D,!E] 10 • [F,!D,!C,!E] 11 12 • ──┤ B ├──────────── 13 • ~[F,!D,A,!A]~ 14 • ~[F,!D,A,!C,D,E]~ 15 • A[F,!D,A,!C,!E] 16 • ~[!A,!C,D,E,F,!D]~ 17 • ~[!A,!C,D,E,A]~ 18 • ~[!A,!C,D,E,A,!D,!E]~ 19 • A[!A,!C,!D,!E,F] 20 • ~[!A,!C,!D,!E,A,D,E]~ 21 • ~[!A,!C,!D,!E,A]~ 22 23 • ──┤ A ├──────────── 24 • [F,!D,!C,!E] 25 -
entailantecedent :: Expressionconsequent :: ExpressionAutomatically constructs a (Gentzen-style) sequent calculus tree that branches bottom-up.
Bugs:
- boolexman requires both antecedent and consequent to be non empty
(i.e. non
()) expressions. As a workaround, you can supply an expression that consists of a single symbol that does not appear in the other expression.
Example:
1> entail (Q) (if A iff not B then C implies D xor E else F or not D)entail Q ((A <=> !B) ? (C => (D + E)) : (F v !D)) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1(a). Transform all if-then-else (ITE) expressions in the condition: No ITE expressions are found in the condition! 1(b). Transform all if-then-else (ITE) expressions in the consequence: • ((A <=> !B) ? (C => (D + E)) : (F v !D)) is transformed into (((A <=> !B) ^ (C => (D + E))) v (!(A <=> !B) ^ (F v !D))) After all ITE expressions in the entailment are transformed: Q |- (((A <=> !B) ^ (C => (D + E))) v (!(A <=> !B) ^ (F v !D))) 2(a). Transform all if-and-only-if (IFF) expressions in the condition: No IFF expressions are found in the condition! 2(b). Transform all if-and-only-if (IFF) expressions in the consequence: • (A <=> !B) is transformed into !(A + !B) • (A <=> !B) is transformed into !(A + !B) After all IFF expressions in the entailment are transformed: Q |- ((!(A + !B) ^ (C => (D + E))) v (!!(A + !B) ^ (F v !D))) 3(a). Transform all exclusive-or (XOR) expressions in the condition: No XOR expressions are found in the condition! 3(b). Transform all exclusive-or (XOR) expressions in the consequence: • (A + !B) is transformed into ((A v !B) ^ (!A v !!B)) • (D + E) is transformed into ((D v E) ^ (!D v !E)) • (A + !B) is transformed into ((A v !B) ^ (!A v !!B)) After all XOR expressions in the entailment are transformed: Q |- ((!((A v !B) ^ (!A v !!B)) ^ (C => ((D v E) ^ (!D v !E)))) v (!!((A v !B) ^ (!A v !!B)) ^ (F v !D))) ────────────────── (F) A, E, D, C, Q |- B ────────────────────── (!L) !B, A, E, D, C, Q |- ────────────────── (F) ────────────────── (F) ─────────────────────────── (!R) A, C, Q |- B, D, E B, E, D, C, Q |- A A, E, D, C, Q |- !!B ────────────────────── (!L) ────────────────────── (!R) ──────────────────────────────── (!R) !B, A, C, Q |- D, E E, D, C, Q |- A, !B E, D, C, Q |- !A, !!B ─────────────── (F) ─────────────── (F) ────────────────── (F) ─────────────────────────── (!R) ─────────────────────────── (!R) ───────────────────────────────────── (!R) D, B, A, Q |- F D, Q |- B, A, F B, C, Q |- D, E, A A, C, Q |- D, E, !!B D, C, Q |- !E, A, !B D, C, Q |- !E, !A, !!B ─────────────────── (!R) ─────────────────── (!R) ────────────────────── (!R) ──────────────────────────────── (!R) ──────────────────────────────── (!R) ────────────────────────────────────────── (!R) B, A, Q |- F, !D Q |- B, A, F, !D C, Q |- D, E, A, !B C, Q |- D, E, !A, !!B C, Q |- !D, !E, A, !B C, Q |- !D, !E, !A, !!B ──────────────── (I) ──────────────────────── (!R) ──────────────────────── (!L) ────────────────── (I) ─────────────────────────── (vR) ───────────────────────────────────── (vR) ───────────────────────────────────── (vR) ─────────────────────────────────────────────── (vR) ─────────────── (F) A, Q |- A, F, !D A, Q |- !B, F, !D !B, Q |- A, F, !D !B, Q |- !B, F, !D C, Q |- (A v !B), D, E C, Q |- (!A v !!B), D, E C, Q |- (A v !B), !D, !E C, Q |- (!A v !!B), !D, !E E, D, C, Q |- F ──────────────────── (!L) ───────────────────────────── (!L) ───────────────────────────── (!L) ────────────────────── (!L) ───────────────────────────────────────────────────────────────────────────── (^R) ───────────────────────────────────────────────────────────────────────────────────────────────── (^R) ────────────────── (I) ─────────────────── (!R) !A, A, Q |- F, !D !!B, A, Q |- F, !D !A, !B, Q |- F, !D !!B, !B, Q |- F, !D C, Q |- ((A v !B) ^ (!A v !!B)), D, E C, Q |- ((A v !B) ^ (!A v !!B)), !D, !E D, C, Q |- F, D, E D, C, Q |- F, !E ────────────────────────────────────────────────────────────── (vL) ──────────────────────────────────────────────────────────────── (vL) ────────────────────────────────────────────────────────────────────────────────── (!L) ────────────────────────────────────────────────────────────────────────────────────────────────────── (!L) ────────────────────── (!R) ──────────────────────── (!R) A, Q, (!A v !!B) |- F, !D !B, Q, (!A v !!B) |- F, !D !((A v !B) ^ (!A v !!B)), C, Q |- D, E !((A v !B) ^ (!A v !!B)), C, Q |- !D, !E C, Q |- F, !D, D, E C, Q |- F, !D, !E ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (vL) ─────────────────────────────────────────────────────────────────────────────────────── (!R) ─────────────────────────────────────────────────────────────────────────────────────────────────────────── (!R) ─────────────────────────── (vR) ───────────────────────────── (vR) Q, (A v !B), (!A v !!B) |- F, !D C, Q |- !!((A v !B) ^ (!A v !!B)), D, E C, Q |- !!((A v !B) ^ (!A v !!B)), !D, !E C, Q |- (D v E), F, !D C, Q |- (!D v !E), F, !D ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (^L) ──────────────────────────────────────────────────────────────────────────────────────────── (vR) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────── (vR) ───────────────────────────────────────────────────────────────────── (^R) ((A v !B) ^ (!A v !!B)), Q |- F, !D C, Q |- (D v E), !!((A v !B) ^ (!A v !!B)) C, Q |- (!D v !E), !!((A v !B) ^ (!A v !!B)) C, Q |- ((D v E) ^ (!D v !E)), F, !D ─────────────────────────────────────────────────────── (I) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (!R) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (^R) ────────────────────────────────────────────────────────────────────────── (=>R) !((A v !B) ^ (!A v !!B)), Q |- !((A v !B) ^ (!A v !!B)) Q |- !((A v !B) ^ (!A v !!B)), F, !D C, Q |- ((D v E) ^ (!D v !E)), !!((A v !B) ^ (!A v !!B)) Q |- (C => ((D v E) ^ (!D v !E))), F, !D ─────────────────────────────────────────────────────────── (!R) ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (vR) ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (=>R) ──────────────────────────────────────────────────────────────────────────────── (vR) Q |- !!((A v !B) ^ (!A v !!B)), !((A v !B) ^ (!A v !!B)) Q |- (F v !D), !((A v !B) ^ (!A v !!B)) Q |- !!((A v !B) ^ (!A v !!B)), (C => ((D v E) ^ (!D v !E))) Q |- (F v !D), (C => ((D v E) ^ (!D v !E))) ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (^R) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (^R) Q |- !((A v !B) ^ (!A v !!B)), (!!((A v !B) ^ (!A v !!B)) ^ (F v !D)) Q |- (C => ((D v E) ^ (!D v !E))), (!!((A v !B) ^ (!A v !!B)) ^ (F v !D)) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (^R) Q |- (!((A v !B) ^ (!A v !!B)) ^ (C => ((D v E) ^ (!D v !E)))), (!!((A v !B) ^ (!A v !!B)) ^ (F v !D)) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── (vR) Q |- ((!((A v !B) ^ (!A v !!B)) ^ (C => ((D v E) ^ (!D v !E)))) v (!!((A v !B) ^ (!A v !!B)) ^ (F v !D))) - boolexman requires both antecedent and consequent to be non empty
(i.e. non
In order of precedence:
| Operator | Opeartor (symbolic) | Associativity |
|---|---|---|
| not | ! | N/A (prefix operator) |
| and | ^ | Associative |
| xor | + | Associative |
| or | v | Associative |
| implies | => | Right-Associative |
| iff | <=> | Associative |
| if-then-else | ( ? : ) | N/A (must always be enclosed in parantheses) |
For instance
subexpressions (A ? (B ? C : D) : E xor not F and G implies H or I iff J)
would be interpreted as
subexpressions (A ? (B ? C : D) : (((E xor (not F and G)) implies (H or I)) iff J))
As mentioned previously, boolexman pipes its output through less to
provide a more convenient interface to its users, which in turn, also allows
them to save the output of the commands they execute.
To save the output of a command:
- Execute your command as usual.
- Press
s(small-case!) while viewing the output of your command.- You should see a prompt at the bottom of your terminal
log file:, if not, check the documentation of your operating system (your version oflessmight not have this functionality). - To cancel, press BACKSPACE; the prompt at the bottom of your terminal
should turn back into
:or(END).
- You should see a prompt at the bottom of your terminal
- Enter the name of the file you would like to save into, and press ENTER
(RETURN).
- If the file(name) you just entered already exists, you'll see the warning
Warning: "FILENAME" exists; Overwrite, Append or Don't log?at the prompt ofless. PressingOwill overwrite, and pressingDwill cancel the operation. You can also pressAto append to the file, but that is probably not what you want.
- If the file(name) you just entered already exists, you'll see the warning
- Done! The prompt at the bottom of your terminal should turn back into
:or(END).
In its most general form:
<VERB> <VERB SPECIFIC ARGUMENTS...>
The definitions below should be decipherable to many, although beware that none of them are formal definitions (especially with respect to the spaces).
-
<VERB>[A-Za-z]+ -
<SYMBOL>[A-Z][a-z]*TrueandFalseare reserved symbols, meaning true and false respectively. -
<LIST OF SYMBOLS>\[<SYMBOL>(, <SYMBOL>)*\] -
<PREFIX OPERATOR>(! | not) -
<INFIX OPERATOR>(and | ^ | xor | \+ | or | v | implies | => | iff | <=>) -
<ITE EXPRESSION>\((if <EXPRESSION> then <EXPRESSION> else <EXPRESSION> | <EXPRESSION> \? <EXPRESSION> : <EXPRESSION>)\) -
<EXPRESSION>(<SYMBOL> | <PREFIX OPERATOR> <EXPRESSION> | <EXPRESSION> <INFIX OPERATOR> <EXPRESSION> | <ITE EXPRESSION>)
The ISC License, see LICENSE for details.
Copyright (c) 2018 Mert Bora ALPER [email protected]
Beware that boolexman used to use GNU Readline library prior to the commit c93cb4350823832fc42883661f152c523d767bd4, but mistakenly said to be licensed under The ISC License where it should have been The General Public License (due to the Copyleft clause).
In no specific order, I am grateful
- to Prof. Michael Fourman for teaching us the principles of logic, which I relied on extensively in developing this program, and of computation.
- to Prof. Don Sannella for teaching us functional programming, which enabled me to complete this program in less than two months thanks to the expressivity (and type system) of Haskell.
- and to both of them, because Curry–Howard correspondence! =)