From: Steve Lawrence <slawrence@apache.org>
Sent: Thursday, August 29, 2019 1:30 PM
To: users@daffodil.apache.org
Subject: Re: Plus '+' sign and lax textNumberCheckPolicy - was: Re: How to model a fixed-length integer that may be padded with space on the left?

I think this is a difference in ICU version?

A little grepping through ICU source, I found a change [1] to their
number parsing logic in Dec 2017:

+        if (!isStrict) {
+            parser.addMatcher(WhitespaceMatcher.getInstance());
+            parser.addMatcher(new PlusSignMatcher());
+        }

That looks to me like a change to make it so plus signs are always
matched in lax/lenient mode regardless of the pattern (Daffodils current
behavior). A couple minor changes have been made to that section, but
nothing that allows you to turn if off if lenient is on.

It's hard to tell in the git history what release that was in, but it
looks like around version 61, which is relatively new (Daffodil is on
version 62).

Also, the latest version of DecimalFormatProperties.java (looks to be an
internal implementation, so no online javadocs), has javadocs that
states that plus signs are always allowed in lenient/lax mode [2].

I think this is a change in ICU behavior in newer versions.

- Steve

[1]
https://github.com/unicode-org/icu/commit/68340c8464bd988477d6c88f46f9dfe4562a6d02#diff-565b07c255337881b4e06f766691667cR119-R122
[2]
https://github.com/unicode-org/icu/blob/master/icu4j/main/classes/core/src/com/ibm/icu/impl/number/DecimalFormatProperties.java#L53-L54