RosettaCodeData/Task/Run-length-encoding/M2000-Interpreter/run-length-encoding.m2000

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Module RLE_example {
inp$="WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW"
Print "Input: ";inp$
Function RLE$(r$){
Function rle_run$(&r$) {
if len(r$)=0 then exit
p=1
c$=left$(r$,1)
while c$=mid$(r$, p, 1) {p++}
=format$("{0}{1}",p-1, c$)
r$=mid$(r$, p)
}
def repl$
while len(r$)>0 {repl$+=rle_run$(&r$)}
=repl$
}
RLE_encode$=RLE$(inp$)
Print "RLE Encoded: ";RLE_encode$
Function RLE_decode$(r$) {
def repl$
def long m, many=1
while r$<>"" and many>0 {
many=val(r$, "INT", &m)
repl$+=string$(mid$(r$, m, 1), many)
r$=mid$(r$,m+1)
}
=repl$
}
RLE_decode$=RLE_decode$(RLE_encode$)
Print "RLE Decoded: ";RLE_decode$
Print "Checked: ";RLE_decode$=inp$
}
RLE_example