[jboss-jira] [JBoss JIRA] (DROOLS-3088) FEEL Compiler: refactor to AST-based tree walk

Edoardo Vacchi created DROOLS-3088: -------------------------------------- Summary: FEEL Compiler: refactor to AST-based tree walk Key: DROOLS-3088 URL: https://issues.jboss.org/browse/DROOLS-3088 Project: Drools Issue Type: Task Reporter: Edoardo Vacchi Assignee: Edoardo Vacchi Current implementation of the compiler walks the parse tree generated by ANTLR, which is a bit cumbersome because of the way the grammar has to be written to deal with priorities/ambiguities. Luckily, many of such issues are solved by the interpreter implementation, which walks the parse tree and generates a neat, simpler Abstract Syntax Tree. This tasks is to refactor our current compiler to walk that AST, instead of the larger parse tree. Benefits: - less "visit" cases in the visitor - more opportunities to "optimize" the tree (e.g, tree rewrites, constant folding) - more opportunities to refactor tree walking phases (e.g. we could add a "type-evaluation" phase) - a chance to refactor code gen utilities to support classes, and simplify the code in general - cons: it takes a bit of time, but the AST nodes are really a handful, so it should not take that much -- This message was sent by Atlassian Jira (v7.12.1#712002)