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import std.stdio;
import std.string;
import std.conv;
import std.typecons;
import std.container : SList;
import std.container : DList;
import std.variant;
alias Token = Algebraic!(int, string);
SList!Token stack;
DList!Token[string] words;
int[string] variables;
Nullable!(DList!Token) definition;
void startDefinition()
in { assert( definition.isNull); }
out { assert(!definition.isNull); }
body {
definition = DList!Token();
}
void endDefinition()
in { assert(!definition.isNull); }
out { assert( definition.isNull); }
body {
string wordToBeDefined;
definition.front.visit!(
(int x ) => wordToBeDefined = "",
(string name) => wordToBeDefined = name
);
if ( wordToBeDefined == "" ) {
throw new Exception("words may not be numeric");
}
definition.removeFront;
words[wordToBeDefined] = definition;
definition.nullify;
}
void append(ref Nullable!(DList!Token) definition, int value) {
definition.insertBack(Token(value));
}
void append(ref Nullable!(DList!Token) definition, string word) {
if ( word == ";" ) {
endDefinition();
} else {
definition.insertBack(Token(word));
}
}
void evaluate(string word) {
switch ( word ) {
case "ยง":
startDefinition();
break;
case "$":
string name = stack.pop().get!string;
int value = stack.pop().get!int;
variables[name] = value;
break;
case "@":
string name = stack.pop().get!string;
if ( name in variables ) {
stack.push(variables[name]);
}
break;
case "+":
int b = stack.pop().get!int;
int a = stack.pop().get!int;
stack.push(a + b);
break;
case "*":
int b = stack.pop().get!int;
int a = stack.pop().get!int;
stack.push(a * b);
break;
case "/":
int b = stack.pop().get!int;
int a = stack.pop().get!int;
if ( b == 0 ) {
throw new Exception("division by 0 undefined");
} else {
stack.push(a / b);
}
break;
case "%":
int b = stack.pop().get!int;
int a = stack.pop().get!int;
if ( b == 0 ) {
throw new Exception("modulo 0 undefined");
} else {
stack.push(a % b);
}
break;
case ".":
stack.pop;
break;
case "'":
writeln(stack.top);
break;
default:
if ( word in words ) {
foreach ( token; words[word] ) {
process(token);
}
} else {
stack.push(word);
}
}
}
void process(Token token) {
token.visit!(
(int x ) => process(x),
(string word) => process(word)
);
}
void process(int x) {
stack.push(x);
}
void process(string word) {
try {
evaluate(word);
}
catch (Exception ex) {
writeln("Error: ", ex.msg);
}
}
void push(ref SList!Token stack, int value) {
if ( definition.isNull ) {
stack.insertFront(Token(value));
} else {
definition.append(value);
}
}
void push(ref SList!Token stack, string word) {
if ( definition.isNull ) {
stack.insertFront(Token(word));
} else {
definition.append(word);
}
}
Token top(ref SList!Token stack) {
if ( stack.empty ) {
throw new Exception("stack is empty");
} else {
return stack.front;
}
}
Token pop(ref SList!Token stack) {
Token token = stack.top;
stack.removeFront;
return token;
}
void main() {
while ( !stdin.eof ) {
foreach ( token; stdin.readln.split ) {
if ( definition.isNull ) {
if ( token.isNumeric ) {
process(parse!int(token));
} else {
process(token);
}
} else {
if ( token.isNumeric ) {
definition.append(parse!int(token));
} else {
definition.append(token);
}
}
}
}
}
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