[LUCENE-5754] Allow "$" in expression variables

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.9, 6.0
• Component/s: modules/expressions
• Lucene Fields: New
• Assignee: Uwe Schindler
• Reporter: Uwe Schindler
• Created: 12/Jun/14 10:56
• Updated: 28/Aug/22 14:09
• Resolved: 13/Jun/14 08:56

Description

The current expressions modules only allows ASCII letters, ASCII digits and the underscore in variable names.

It is quite common to javascript developers to use also the dollar sign as identifier part (especially at the beginning of an identifier, see the famous "jQuery" $-function). This would allow bindings like "$score".

The official ECMAScript spec allows the $: http://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%203rd%20edition,%20December%201999.pdf (see section 7.6)

The other stuff there like unicode escapes and all unicode letter crazyness should be excluded for simplicity.

Adding the "$" is just a one-line change in the grammar and does not conflict with anything else, because "$" is not a special character to javascript.

Issue Links

• relates to: SOLR-5707 Lucene Expressions in Solr