Dominant Macros

[marcioAlmada]

Currently, by default, a macro backtracks if it's pattern is not fulfilled. But in many cases it would be useful to prevent backtracking after a given entry point is reached.

The idea is to use a single · (middle dot) to denote a "point of no return" in a macro pattern, as in:

macro {
    unless · (···expression) {
        ···body
    }
} >> {
    if (! (···expression)) {
        ···body
    }
}

So any wrong usage of the macro after the arbitrary entry point would throw some variant of syntax error:

unless ($x === 1);
// Unexpected ';' on line 1, expected '{'

I'm still unsure if this is a reasonable way to implement dominant macros. Maybe "dominant" should be the default behavior and a tag to allow backtracking (macro ·allow_backtrack {...} >> {...}) could be a better option.

[marcioAlmada]

✅