Minimal Brainfuck interpreter in R

Brainfuck.r

library(DescTools)

progstr <- ">++++++++[<+++++++++>-]<.>++++[<+++++++>-]<+.+++++++..+++.>>++++++[<+++++++>-]<++.------------.>++++++[<+++++++++>-]<+.<.+++.------.--------.>>>++++[<++++++++>-]<+."
prog <- unlist(strsplit(progstr, ""))
cells <- rep(0, times=30)
pointer <- 1
charIdx <- 1
loopIdxs <- list()

while (charIdx <= length(prog)) {
    char <- prog[charIdx]

    if (char == "+") {
        cells[pointer] <- cells[pointer] + 1
    } else if (char == "-") {
        cells[pointer] <- cells[pointer] - 1
    } else if (char == ">") {
        pointer <- pointer + 1
    } else if (char == "<") {
        pointer <- pointer - 1
    } else if (char == ".") {
        cat(AscToChar(cells[pointer]))
    } else if (char == "[") {
        loopIdxs <- append(loopIdxs, charIdx)
    } else if (char == "]") {
        if (cells[pointer] == 0) {
            loopIdxs = head(loopIdxs, -1)
        } else {
            charIdx = tail(loopIdxs, n=1)[[1]]
        }
    }

    charIdx <- charIdx + 1
}

Standalone.r

# Standalone version (without dependency on DescTools)

asciitable = c("", "", "", "", "", "", "", "", "", "\t", "\n", "\x0b", "\x0c", "\r", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", " ", "!", "\"", "#", "$", "%", "&", "'", "(", ")", "*", "+", ",", "-", ".", "/", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", ":", ";", "<", "=", ">", "?", "@", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "[", "\\", "]", "^", "_", "`", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "{", "|", "}", "~", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "")

progstr <- ">++++++++[<+++++++++>-]<.>++++[<+++++++>-]<+.+++++++..+++.>>++++++[<+++++++>-]<++.------------.>++++++[<+++++++++>-]<+.<.+++.------.--------.>>>++++[<++++++++>-]<+."
prog <- unlist(strsplit(progstr, ""))
cells <- rep(0, times=30)
pointer <- 1
charidx <- 1
loopidxs <- list()

while (charidx <= length(prog)) {
    char <- prog[charidx]

    if (char == "+") {
        cells[pointer] <- cells[pointer] + 1
    } else if (char == "-") {
        cells[pointer] <- cells[pointer] - 1
    } else if (char == ">") {
        pointer <- pointer + 1
    } else if (char == "<") {
        pointer <- pointer - 1
    } else if (char == ".") {
        cat(asciitable[cells[pointer]+1])
    } else if (char == "[") {
        loopidxs <- append(loopidxs, charidx)
    } else if (char == "]") {
        if (cells[pointer] == 0) {
            loopidxs = head(loopidxs, -1)
        } else {
            charidx = tail(loopidxs, n=1)[[1]]
        }
    }

    charidx <- charidx + 1
}