104 lines
4.8 KiB
Markdown
104 lines
4.8 KiB
Markdown
# Truth Table
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This is a simple truth table generator. For more information about truth tables,
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please see the [relevant Wikipedia article][1].
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[1]: https://en.wikipedia.org/wiki/Truth_table
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There is an instance of the web version of this program hosted here: [tt.zander.im][2]
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[2]: https://tt.zander.im/
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This repository contains three things: a Common Lisp library to parse and
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manipulate propositional logic expressions, a command line truth table
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generator, and a web-based truth table generator.
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Building the CLI executable requires SBCL. Both the CLI and web server need
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Quicklisp. If you have Quicklisp installed, it should just get the rest of the
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dependencies for you.
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### CLI
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To build the CLI version, just run `make`.
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Here is the help output from the CLI program:
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```text
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usage: truth-table [options] <propositions...>
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-h, --help print this message, then exit
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--syntax-help print a syntax help message, then exit
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-f, --format=<arg> specify the output format (*unicode*, ascii, latex, or html)
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-s, --subexps include sub-expressions in the output table
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-n, --no-vars do not include variables in the output table
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-m, --multi-char allow multi-character variable names
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-i, --no-implicit do not use implicit 'and' operations
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-p, --pretty pretty print latex, html, etc. output
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-l, --latin use the Latin T and F characters for truth values
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The choice surrounded by '*' is the default. Arguments to long
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options are also required for their short variant.
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```
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Here is an example truth table:
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```text
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$ truth-table '(a /\ b) -> ~b'
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┌───┬───┬────────────┐
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│ a │ b │ a ∧ b → ¬b │
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├───┼───┼────────────┤
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│ ⊤ │ ⊤ │ ⊥ │
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│ ⊤ │ ⊥ │ ⊤ │
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│ ⊥ │ ⊤ │ ⊤ │
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│ ⊥ │ ⊥ │ ⊤ │
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└───┴───┴────────────┘
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```
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### Web
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To run the web server, execute `./truth-table-web-wrapper`. If you want to run
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it in the background, I recommend using something like GNU Screen. It should be
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noted, however, that it does not support HTTPS. If you want to use HTTPS, run
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the web server behind something like Nginx or HAProxy.
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Here is the help output for the web wrapper program:
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```text
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usage: truth-table-web-wrapper [options]
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-h, --help print this message, then exit
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-d, --debug enable debug output
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-p, --port=<arg> specify port to use (default: 8000)
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-a, --address=<arg> specify address to bind to (default: 127.0.0.1)
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Arguments to long options are also required for their short variant.
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```
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### Syntax
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Here is the syntax for propositions (this is the same for both the web server
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and the CLI):
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```text
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$ truth-table --syntax-help
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┌───────────────────┬────────────────────────────────────────────┐
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│ Operator │ Syntax │
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├───────────────────┼────────────────────────────────────────────┤
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│ open parenthesis │ ( │
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│ close parenthesis │ ) │
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│ and │ &, &&, ., /\, and, ∧ │
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│ nand │ !&, !&&, nand, ~&, ~&&, ↑, ⊼ │
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│ or │ +, \/, or, |, ||, ∥, ∨ │
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│ nor │ !|, !||, nor, ~|, ~||, ↓, ⊽ │
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│ exclusive or │ !=, ^, xor, ↮, ≢, ⊕, ⊻ │
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│ not │ !, not, ~, ¬ │
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│ implies │ ->, =>, >, implies, →, ⇒, ⊃, ⟹ │
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│ converse │ <, <-, <=, converse, ←, ⇐, ⊂, ⟸ │
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│ biconditional │ <->, <=>, <>, =, ==, iff, xnor, ↔, ⇔, ≡, ⊙ │
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└───────────────────┴────────────────────────────────────────────┘
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┌─────────┬────────────────┐
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│ Operand │ Syntax │
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├─────────┼────────────────┤
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│ true │ 1, t, true, ⊤ │
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│ false │ 0, f, false, ⊥ │
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└─────────┴────────────────┘
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Two operands next to each other is treated as an 'implicit and' (unless this
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feature is disabled).
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Example:
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abc|d = a ∧ b ∧ c ∨ d
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```
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