February 2011 Archives

Perl and Parsing 7: Do List Operators have Left/Right Precedence?

Chiral Operators

the syntax of Perl's list operators is quite natural. Descriptions of that syntax, however, tend to be awkward.

The current practice is to describe this syntax in terms of "left precedence" and "right precedence". In other words, list operators are said to be chiral. I have problems with the Chiral Interpretation of list operators. The most serious of these: the Chiral Interpretation does not actually account for the behavior of expressions that contain list operators.

In this post, I assume you have a working knowledge of one or more list operato…

About Jeffrey Kegler

user-pic I blog about Perl, with a focus on parsing and Marpa, my parsing algorithm based on Jay Earley's.