compile/item

Symbol: compile/item

Syntax: (item OBJ KEY)

Use-case: Load the item at key KEY from OBJ (subscript/getitem).

Behaviour: Compiles OBJ, then KEY, then emits ITEM, and the compress pipeline folds a symbol OBJ and a constant or symbol KEY into the row that names them (ITEM_CONST, ITEM_VAR, VAR_ITEM_CONST, VAR_ITEM_VAR, and their FAST twins in a function body). When OBJ is a symbol and KEY is neither a constant nor a symbol, the key compiles to the stack and the special emits VAR_ITEM, which names the object, since no fold reaches an object load behind a computed key. A named object or key is fetched when the row runs.

Examples:

(item vec 0)
(item tbl (compute-key))