Scala-native: Support for scala-native/re2s

Created on 11 Jan 2019 · 5Comments · Source: scala-native/scala-native

Unfortunately, scala-native is missing just a few Char/Array/etc methods needed to use re2s instead of the re2 dependency; switching to re2s would be a big win for setup and portability, since C++ libs are quite a challenge to compile and link directly.

If I try to link the following short program:

import re2s.RE2

object main {
  def main(args:Array[String]):Unit = {
    val request_pattern = new RE2("\\w+ \\w+ \\w+")
    val input = "foo bar baz"
    val result = request_pattern.match_(input)
    println(result)
  }
}

I get these link errors:

[error] cannot link: @java.lang.Character$::codePointAt_java.lang.CharSequence_i32_i32
[error] cannot link: @java.lang.Character$::codePointBefore_java.lang.CharSequence_i32_i32
[error] cannot link: @java.lang.StringBuilder::indexOf_java.lang.String_i32_i32
[error] cannot link: @java.util.ArrayList::listIterator_i32_java.util.ListIterator
[error] cannot link: @java.util.ArrayList::listIterator_java.util.ListIterator
[error] cannot link: @java.util.ArrayList::removeRange_i32_i32_unit
[error] cannot link: @java.util.ArrayList::subList_i32_i32_java.util.List
[error] cannot link: @java.util.List::toArray_scala.scalanative.runtime.ObjectArray_scala.scalanative.runtime.ObjectArray

Most of those would be pretty straightforward to implement; however, the unicode code-point logic might be a bit of a pain. We might consider handling ascii only for a first pass, and raising an exception if bytes > 127 are found, to keep the initial implementation simple.

javalib

Source

rwhaling

Most helpful comment

Scala Native itself already has codePointAt and codePointBefore (herehttps://github.com/scala-native/scala-native/blob/01fbdf7cf6f1f9f62982eab30a35eeb2f7c735ca/javalib/src/main/scala/java/lang/Character.scala#L239-L279)), just for Array[Char] instead of CharSequence. You can just delegate the CharSequence ones to the Array[Char] ones, or copy-paste-and-adapt them. They're really not difficult.