@masala/parser/src/test/genlex/genlex-brainfuck-test.js

Masala Parser

import { GenLex } from '../../lib/genlex/genlex'
import { F, C } from '../../lib/parsec/index'
import Streams from '../../lib/stream'

function createParser() {
    const genlex = new GenLex()
    genlex.setSeparatorsParser(F.not(C.charIn('+-<>[],.')))
    genlex.keywords(['+', '-', '<', '>', '[', ']', ',', '.'])
    const grammar = F.any()
        .map((token) => token.value)
        .rep()

    return genlex.use(grammar)
}

export default {
    setUp: function (done) {
        done()
    },

    'parser is valid': function (test) {
        let hW =
            '++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.'

        let parser = createParser()
        const response = parser.parse(Streams.ofString(hW))

        test.ok(response.isAccepted())
        test.equals(response.offset, hW.length)

        test.done()
    },

    'comments are accepted': function (test) {
        // Taken from Wikipedia documentation
        let hW = `++++++++               Set Cell #0 to 8
[
    >++++               Add 4 to Cell #1; this will always set Cell #1 to 4
    [                   as the cell will be cleared by the loop
        >++             Add 2 to Cell #2
        >+++            Add 3 to Cell #3
        >+++            Add 3 to Cell #4
        >+              Add 1 to Cell #5
        <<<<-           Decrement the loop counter in Cell #1
    ]                   Loop till Cell #1 is zero; number of iterations is 4
    >+                  Add 1 to Cell #2
    >+                  Add 1 to Cell #3
    >-                  Subtract 1 from Cell #4
    >>+                 Add 1 to Cell #6
    [<]                 Move back to the first zero cell you find; this will
                        be Cell #1 which was cleared by the previous loop
    <-                  Decrement the loop Counter in Cell #0
]                       Loop till Cell #0 is zero; number of iterations is 8

The result of this is:
Cell No :   0   1   2   3   4   5   6
Contents:   0   0  72 104  88  32   8
Pointer :   ^

>>.                     Cell #2 has value 72 which is 'H'
>---.                   Subtract 3 from Cell #3 to get 101 which is 'e'
+++++++..+++.           Likewise for 'llo' from Cell #3
>>.                     Cell #5 is 32 for the space
<-.                     Subtract 1 from Cell #4 for 87 to give a 'W'
<.                      Cell #3 was set to 'o' from the end of 'Hello'
+++.------.--------.    Cell #3 for 'rl' and 'd'
>>+.                    Add 1 to Cell #5 gives us an exclamation point
>++.                    And finally a newline from Cell #6`

        let parser = createParser()
        const response = parser.parse(Streams.ofString(hW))

        test.ok(response.isAccepted())
        test.equals(response.offset, 106) // there is 111 tokens

        test.done()
    },
}