package org.jabref.logic.bst;
import java.util.Stack;
import org.jabref.logic.bst.VM.BstEntry;
import org.jabref.logic.bst.VM.BstFunction;
/**
* The |built_in| function {\.{width\$}} pops the top (string) literal and
* pushes the integer that represents its width in units specified by the
* |char_width| array. This function takes the literal literally; that is, it
* assumes each character in the string is to be printed as is, regardless of
* whether the character has a special meaning to \TeX, except that special
* characters (even without their |right_brace|s) are handled specially. If the
* literal isn't a string, it complains and pushes~0.
*
*/
public class WidthFunction implements BstFunction {
private final VM vm;
public WidthFunction(VM vm) {
this.vm = vm;
}
@Override
public void execute(BstEntry context) {
Stack<Object> stack = vm.getStack();
if (stack.isEmpty()) {
throw new VMException("Not enough operands on stack for operation width$");
}
Object o1 = stack.pop();
if (!(o1 instanceof String)) {
vm.warn("A string is needed for change.case$");
stack.push(0);
return;
}
stack.push(BibtexWidth.width((String) o1));
}
}