[Pitch] Regular Expression Literals

[kylemacomber]

@breathe

PCRE is NOT the pinnacle of a regex literal design and choosing it for historical reasons is a major mistake and lost opportunity in my opinion. I'd much rather see a good regex literal design.

We cataloged some of the same shortcomings of traditional regex syntax in the overview, specifically the "From Regex to Pattern" section. This is why we're also proposing a result builder based Pattern DSL.

In fact, to my eye your proposed syntax isn't so different from the Pattern DSL we're planning:

@breathe

let identifier = #re { alpha word* }
let hexdigit = #re { "0x" ("A"..."F" | "a"..."f")+ }
let someDumbExpression = #re { identifier "=" identifier ("+" | "*" | "-") hexdigit newline }

As we wrote there:

@Michael_Ilseman

Do we want both Pattern and Regex ?

Yes!

Pattern uses a more versatile syntax (just regular Swift code!) and supports matching more complex languages than Regex . But Pattern can't compete with the familiarity and ubiquity of traditional regular expression syntax.