package net.sf.jabref.bst;
import java.util.Stack;
import net.sf.jabref.bst.VM.BstEntry;
import net.sf.jabref.bst.VM.BstFunction;
/**
* From the Bibtex manual:
*
* Pops the top two (string) literals; it changes the case of the second
* according to the specifications of the first, as follows. (Note: The word
* `letters' in the next sentence refers only to those at brace-level 0, the
* top-most brace level; no other characters are changed, except perhaps for
* \special characters", described in Section 4.) If the first literal is the
* string `t', it converts to lower case all letters except the very first
* character in the string, which it leaves alone, and except the first
* character following any colon and then nonnull white space, which it also
* leaves alone; if it's the string `l', it converts all letters to lower case;
* and if it's the string `u', it converts all letters to upper case. It then
* pushes this resulting string. If either type is incorrect, it complains and
* pushes the null string; however, if both types are correct but the
* specification string (i.e., the first string) isn't one of the legal ones, it
* merely pushes the second back onto the stack, after complaining. (Another
* note: It ignores case differences in the specification string; for example,
* the strings t and T are equivalent for the purposes of this built-in
* function.)
*
* Christopher: I think this should be another grammar! This parser is horrible.
*
*/
public class ChangeCaseFunction implements BstFunction {
VM vm;
public ChangeCaseFunction(VM vm) {
this.vm = vm;
}
public void execute(BstEntry context) {
Stack<Object> stack = vm.getStack();
if (stack.size() < 2) {
throw new VMException("Not enough operands on stack for operation change.case$");
}
Object o1 = stack.pop();
Object o2 = stack.pop();
if (!(o1 instanceof String && ((String) o1).length() == 1)) {
throw new VMException("A format string of length 1 is needed for change.case$");
}
if (!(o2 instanceof String)) {
throw new VMException("A string is needed as second parameter for change.case$");
}
char format = (((String) o1).toLowerCase().charAt(0));
String s = (String) o2;
stack.push(BibtexCaseChanger.changeCase(s, format, vm));
}
}