MR.md

Multiple Replacement

It is easy to replace one string with another in meow. However, when you want to replace multiple strings with multiple strings, it is not that easy. This is because the replacement is done one by one.

For example,

> let "a" "b" let "c" "a" "ac"
bb

We want to replace a with b and c with a. However, the replacement is done one by one, so the first replacement is done, and then the second replacement is done. So, the result is bb.

What if we want to do the replacement simultaneously? It's not easy to see.

This feature doesn't need recursion and it is originally designed to be supported in catlet.

First, we have to make sure that the multiple strings are all independent. Otherwise the result is not expected.

Implementation code for 2 strings:

encat(x,y) {
    {"#$"=""; x} + {"$#"=""; y}
}

enraw(s) {
    "#$" = "";
    "$#" = "";
    encode(s)
}

enrep(s,x,y) {
    enraw(x) = y;
    s
}

rep2(s,x,xr,y,yr) {
    var repx = enrep(encode(s),x,"x#");
    var repy = enrep(repx,y,"y#");
    decode({
        "x#" = enraw(xr);
        "y#" = enraw(yr);
        repy
    })
}

Result for rep2 "ac" "a" "b" "c" "a" is "ba".