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Suppose I'm writing a grammar rule for arithmetics, and for additions, I got this:
Additive-Expression
: Multiplicative-Expression
| Additive-Expression ("+"|"-") Multiplicative-Expression
;
The multiplicative rule is involved to establish the precedence of operators. Q: What's the name of the rule to the right of the colon ":"? Fall-back? Pass-thru? What are the references I can learn more?
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$\begingroup$ Not backed by any real reference, but "atom unit" may be descriptive enough. $\endgroup$DannyNiu– DannyNiu2024年12月30日 11:48:28 +00:00Commented Dec 30, 2024 at 11:48
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$\begingroup$ Or "the atom production rule", or just the "atom rule". $\endgroup$DannyNiu– DannyNiu2024年12月30日 11:56:10 +00:00Commented Dec 30, 2024 at 11:56
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1$\begingroup$ I'd have called it the "base" or "limiting" rule/case (like any recursive definition) or the "degenerate rule/case" as there's no addition going on, after the mathematical use eg "degenerate triangle" en.wikipedia.org/wiki/Degeneracy_(mathematics) $\endgroup$jonathanjo– jonathanjo2024年12月30日 12:34:08 +00:00Commented Dec 30, 2024 at 12:34
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$\begingroup$ @jonathanjo Degeneracy sounds most descriptive. $\endgroup$DannyNiu– DannyNiu2024年12月30日 12:59:38 +00:00Commented Dec 30, 2024 at 12:59
1 Answer 1
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In the Dragon Book, it is called a "unit production" or "marker".
The first term underlines the size of the right-hand side, while the second one refers to the employment of the production to trigger arbitrary code before another more important reduction occurs.
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