Execute Brain****: Difference between revisions
Add R example
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(Add R example) |
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Line 6,838:
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Print this backwards!</pre>
=={{header|R}}==
Unfortunately doesn't support the "," operator.
<syntaxhighlight lang="r">
bf <- function(code) {
instructions <- strsplit(code, "")[[1]]
tape <- c()
visited <- c()
pset <- function(n) {
if (n %in% visited)
p <<- n
else {
visited[length(visited)+1] <<- n
tape[as.character(n)] <<- 0
pset(n)
}
}
bracket <- function(b1, b2, x) {
nest <- 1
j <- i + x
while (nest != 0) {
if (instructions[j] == b1)
nest <- nest + 1
if (instructions[j] == b2)
nest <- nest - 1
j <- j + x
}
i <<- j
}
pset(0)
i <- 1
while (i <= length(instructions)) {
p_ <- as.character(p)
c <- instructions[i]
switch(c,
">" = pset(p + 1),
"<" = pset(p - 1),
"+" = tape[p_] <- tape[p_] + 1,
"-" = tape[p_] <- tape[p_] - 1,
"." = cat(intToUtf8(tape[p_])),
# TODO: IMPLEMENT ","
"[" = if (tape[p_] == 0) {
bracket("[", "]", 1)
i <- i - 1 # off by one error
},
"]" = bracket("]", "[", -1))
i <- i + 1
}
}
bf("++++++++++[>+>+++>+++++++>++++++++++<<<<-]>>>++.>+.+++++++..+++.<<++.>+++++++++++++++.>.+++.------.--------.<<+.<.")
</syntaxhighlight>
To run:
<pre>
R -s --vanilla < bf.r
</pre>
=={{header|Racket}}==
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