Package dev.frostlake.executor

Class LeadingCommentOffset

java.lang.Object
dev.frostlake.executor.LeadingCommentOffset
public final class LeadingCommentOffset extends Object
A statement that BEGINS with comments reports its positions from the first real token, not from the top of the text. Measured across nine shapes, and the rule is one line: the first token after the leading comments becomes line 1, position 0, and everything after it shifts by the same amount. 
   NULL                        line 1 position 0
      NULL                     line 1 position 3   whitespace ALONE still counts
   /* c */ NULL              line 1 position 0
      /* c */   NULL         line 1 position 0   the whitespace around it goes too
   /* c */\nNULL             line 1 position 0   the newline does not advance the line
   /* a\nb */ NULL           line 1 position 0   nor does one INSIDE the comment
   -- c\nNULL                  line 1 position 0
   /* c */ SELECT UPPER(o)   line 1 position 7   the offset SHIFTS, it is not zeroed
   SELECT /* c */ UPPER(o)   line 1 position 15  an INTERIOR comment counts normally

The last two are what make this a re-basing rather than a stripping: only text BEFORE the first token disappears, and a comment between tokens is ordinary text that pushes the offset along.

  • Method Details

    • of

      public static SourcePosition of(String sql)
      Where the statement's first real token begins, or null when nothing needs re-basing — which is every statement that does not open with a comment, whitespace included.
      Parameters:
      sql - the statement's text
      Returns:
      the first token's line and column, or null

    • begin

      public static SourcePosition begin(SourcePosition origin)
      Note this statement's re-basing origin for the rest of its execution.
      Parameters:
      origin - the first real token's place, or null for no re-basing
      Returns:
      whatever origin it displaced, for end(dev.frostlake.executor.expressions.SourcePosition)

    • end

      public static void end(SourcePosition previous)
      Put back whatever begin(dev.frostlake.executor.expressions.SourcePosition) displaced; null clears.

    • rebase

      public static int[] rebase(int line, int position)
      A statement-relative place re-based past the leading comments, or unchanged when there are none. The arithmetic is ExpressionSource.resolve(dev.frostlake.executor.expressions.SourcePosition)'s, inverted: a place on the origin's own line loses the origin's column, a later line keeps its column, and the line count drops by however many lines the comments occupied.
      Parameters:
      line - the place's line, 1-based
      position - its column
      Returns:
      the two re-based, as {line, position}