Hie Fabien,
Seems like an interesting addition to pgbench interface, but not sure where it's required, it'll be good if you may provide some cases where it's utility can be witnessed. Something like where you absolutely need continuations in expression.
While applying it is giving some trailing whitespace errors, please correct them.
As an additional comment you may consider reformatting following snippet
{continuation} { /* ignore */ }
as
{continuation} {
/* ignore */
}
Thanks.
