[CALCITE-1788] Simplify handling of position in the parser

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.13.0
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 11/May/17 22:01
• Updated: 27/Feb/24 22:24
• Resolved: 22/May/17 02:53

Description

Simplify handling of position in the parser by adding a class Span that keeps track of the tokens that have contributed to the current non-terminal.

Some patterns:

• final Span s; declaration of a Span at the top of a production
• s = span(); initializes s to a Span that includes the token we just saw; very often occurs immediately after the first token in the production
• s.end(this); adds the most recent token to span s and evaluates to a SqlParserPosition that spans from beginning to end; commonly used when making a call to a function
• s.add(node); adds a SqlNode's parser position to a span
• s.addAll(nodeList); adds several SqlNodes' parser positions to a span
• s = Span.of(); initializes s to an empty Span, not even including the most recent token; rarely used