macroexpand

Symbol: macroexpand

Syntax: (macroexpand form ns)

Use-case: Expand a source form repeatedly until its head is no longer a macro. This is what the compiler does before compiling the final form. Use macroexpand-1 when you need to inspect intermediate steps.

Behaviour: Like macroexpand-1, but loops: after each successful expansion, the result becomes the new form and expansion is attempted again until the head is not a macro, no transformer matches, or the binding is not Syntax.

Single-expression begin wrappers are stripped after each step, same as macroexpand-1.

The compiler comes from get-compiler for ns.

Relation to the macro: (macroexpand form) and (macroexpand form ns) are handled by the compile/macroexpand macro. The macroexpandq and macroexpandq-1 macros quote the form before calling. See compile/macroexpand and compile/macroexpandq.

Examples:

>>> (macroexpand '(when condition action))
(cond [condition action] [else: None])

The macroexpandq macro quotes for you, so the form is written unquoted:

>>> (macroexpandq (when condition action))
(cond [condition action] [else: None])

;; Direct call with an explicit namespace
(call macroexpand when-form (globals))

See also macroexpand-1 for a single step.