~[keyword] pub tor if { expr: Expression }
| then
| ?else

~[keyword] pub tor cond { expr: Expression }
| c *

// - `keep:` is OPTIONAL and turns the loop into one that STOPS: the emitted body
//   breaks the moment the expression goes false. Omit it and `for` is exactly
//   what it always was — an absent `keep` renders no line at all, so every
//   existing call site emits byte-identical code.
//
//   This started life as a separate `scan` keyword and that was WRONG. The two
//   templates differed by ONE line and shared everything else, across two targets
//   — four procs where two do. That is the two-lowerings-of-one-construct shape
//   this repo keeps getting bitten by (`frag-a-fix-lands-in-one-lowering-path`),
//   installed deliberately by someone who had written that concept's newest
//   section the same morning. A second copy that merely agrees today is the same
//   bug waiting: the next person to improve the JS range handling would have had
//   to remember there were two homes for it. Lars caught it; converging is the
//   concept's own prescription.
~[keyword] pub tor for { expr: Expression, keep: ?Expression }
! each *
| ?done