eval6b

eval6.cpp

GetNextToken()
    ...
    new:        if (StmtIndex >= StmtLen) {         // If we have run out of input, ...
    new:            if (more != NULL && more()) {   // ... try to get some more.
    new:                StmtLen = strlen (statement);
    new:                StmtIndex = 0;              // If we did get more, start at the beginning of the line again.
    new:            }
    new:        }
reinit()
    ...
    old: void proglet_t::reinit (void) {
    new: void proglet_t::reinit (bool more_func (void)) {
    ...
    new:     more = more_func;
    ...
    new:     more = NULL;

    new:     bool (*more) (void);    // Pointer to a function which will fetch more input.

To make use of this we also need to tweak the way we call things, to give the parser a function to call to fetch more input.
main6b.cpp

    new: FILE        *f;
    new: static char line[1000];
    ...
    new: static bool more (void) {
    new:     return GetLine (f, line, sizeof (line));
    new: }
    ...
    new:         prog.reinit(more);
    ...
    old:         if (GetLine (f, line, sizeof (line))) {
    new:         if (more()) {

If our input doesn't come from a file, we can simply replace this version of more() with one that fills the line buffer from the relevant source. If this line is all there is, we can pass a NULL pointer to reinit().