# Anatomy of a production rule

Production is said to be of the form $u \to v$. I want to know if you distinguish $u$ from $v$ giving them some distinguishing names, like LHS/RHS or something alike.

• What exactly is your question? This is more a request to use uniform terminology (good luck with that!). – vonbrand Dec 25 '15 at 15:53
• @vonbrand The question is whether there are distinguishing names for the two sides of the rule. It seems quite clear to me -- perhaps you misread it? – David Richerby Dec 25 '15 at 17:13
• $v$ can be said to be the production of the string $u$ by the rule at hand. – Yves Daoust Dec 27 '15 at 18:25

## 2 Answers

$u$ can be called the 'head' (or left-hand side)

$v$ can be called the 'body' (or right-hand-side)

sources: source-1, source-2

• I've never seen the terms head or body for this, while left hand side and right hand side are common. – reinierpost Feb 21 '18 at 17:53

Yes, I have found it in Parsing techniques: A practical guide

For brevity we write ---> instead of “may be replaced by”; since terminal and non-terminal symbols are now identified as technical objects we shall write them in a typewriter-like typeface. The part before the ---> is called the left-hand side, the part after it the right-hand side.