Difference between revisions of "Prefix Calculator"

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{{LSL Header}}
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== Prefix Calculator ==
 
Created by [[User:Xaviar Czervik|Xaviar Czervik]]. Do whatever you wish with this function: Sell it (good luck), use it, or modify it.
 
Created by [[User:Xaviar Czervik|Xaviar Czervik]]. Do whatever you wish with this function: Sell it (good luck), use it, or modify it.
  
 
Evaluates an expression in prefix notation. I will give a few examples, and let you figure it out yourself. You have a brain: use it.
 
Evaluates an expression in prefix notation. I will give a few examples, and let you figure it out yourself. You have a brain: use it.
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+ 1 2 = 3
 
+ 1 2 = 3
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+ - 1 2 3 = 2
 
+ - 1 2 3 = 2
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/ + 3 2 - +1 2 3 = 1.25
 
/ + 3 2 - +1 2 3 = 1.25
  
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For more information visit http://en.wikipedia.org/wiki/Prefix_notation.
 
For more information visit http://en.wikipedia.org/wiki/Prefix_notation.
  
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Another prefix calculator script is the [[Chatbot]] sample. That script is much less simple, because it handles many more varieties of input, but that script exhibits essentially this same control flow.
  
<pre>
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<source lang="lsl2">
 
list stack;
 
list stack;
  
push(float i) {
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push(float i) { // Float To Integer - Not good to use for large values, but it works. Sue me...
    stack += (integer)(i*10000000);  // Float To Integer - Not good to use for large values, but it works. Sue me...
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    stack += (integer)(i*10000000);
 
}
 
}
  
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}
 
}
  
float peek() {
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float peek() { // Float To Integer - Not good to use for large values, but it works. Sue me...
    return ((float)llList2Integer(stack, -1))/10000000; // Float To Integer - Not good to use for large values, but it works. Sue me...
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    return ((float)llList2Integer(stack, -1))/10000000;
 
}
 
}
  
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     }
 
     }
 
}
 
}
</pre>
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</source>
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[[Category:LSL Library]]
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[[Category:LSL Examples]]

Latest revision as of 17:35, 24 January 2015

Prefix Calculator

Created by Xaviar Czervik. Do whatever you wish with this function: Sell it (good luck), use it, or modify it.

Evaluates an expression in prefix notation. I will give a few examples, and let you figure it out yourself. You have a brain: use it.

+ 1 2 = 3

+ - 1 2 3 = 2

/ + 3 2 - +1 2 3 = 1.25


For more information visit http://en.wikipedia.org/wiki/Prefix_notation.

Another prefix calculator script is the Chatbot sample. That script is much less simple, because it handles many more varieties of input, but that script exhibits essentially this same control flow.


list stack;
 
push(float i) { // Float To Integer - Not good to use for large values, but it works. Sue me...
 
    stack += (integer)(i*10000000); 
}
 
float pop() {
    float i = peek();
    stack = llList2List(stack, 0, -2);
    return i;
}
 
float peek() { // Float To Integer - Not good to use for large values, but it works. Sue me...
 
    return ((float)llList2Integer(stack, -1))/10000000;
}
 
default {
    state_entry() {
        llListen(0, "", llGetOwner(), "");
    }
    listen(integer i, string n, key id, string m) {
        string data = m;
 
        list parsed = llParseString2List(data, [" "], []);
 
        integer i = llGetListLength(parsed);
        while (i--) {
            string data = llList2String(parsed, i);
            string check = (string)((float)data);
            while (llGetSubString(check, -1, -1) == "0") {
                check = llGetSubString(check, 0, -2);
            }
            if (llGetSubString(check, -1, -1) == ".")
                check = llGetSubString(check, 0, -2);
            if (check == data) { // Is it a number?
                push((float)data);
            } else {
                if (llStringLength(data) == 1) {
                    float first = pop();
                    float second = pop();
                    if (data == "+") {
                        push(first + second);
                    }
                    if (data == "-") {
                        push(first - second);
                    }
                    if (data == "*") {
                        push(first * second);
                    }
                    if (data == "/") {
                        push((float)first / (float)second);
                    }
                } else {
                    float first = pop();
                    if (data == "sin") {
                        push(llSin(first));
                    }
                    if (data == "cos") {
                        push(llCos(first));
                    }
                    if (data == "tan") {
                        push(llTan(first));
                    }
                    if (data == "sqrt") {
                        push(llSqrt(first));
                    }
                }
            }
        }
        llOwnerSay((string)pop());
    }
}