Which Antiforms Are In Use?

[bradrn]

As an aid for myself, I made a summary table:

Type	Antiform	Usage	Stable?
BLANK!	nothing	Unset variables	✓
TAG!	tripwire	Unset variable with informative message	✓
WORD!	keyword	Special constant values (e.g. ~null~, ~void~)	✓
GROUP!	splice	Multiple values without a surrounding block	✓
FRAME!	action	Trigger function execution from words	✓
PARAMETER!	hole	Unspecialized slots in a function frame	✓
BLOCK!	pack	Multi-returns from a function	✗
COMMA!	barrier	Discarded by evaluator	✗
ERROR!	raised	Errors raised from a function call	✗
OBJECT!	lazy	(to be confirmed)	✗

[hostilefork]

@bradrn

As an aid for myself, I made a summary table

Very useful. Do note that the %types.r table encodes the type/antiform information, as well as an annotation to say whether it's unstable or not. Such as for splice:

group       "array that evaluates expressions as an isolated group"
~splice~    (CELL_FLAG_FIRST_IS_NODE)
            [any-series? any-branch? any-plain-value?]
            [array       *       *]

And for error:

error       "error context with id, arguments, and stack origin"
~raised~    (CELL_FLAG_FIRST_IS_NODE | CELL_FLAG_SECOND_IS_NODE)
#unstable   [any-inert?]
            [context     +       +]

As much as possible, I like to use Rebol to do code generation for properties in the C (and also to put in the binary for HELP). A string describing the antiform would be good to stick in here...

In any case, %types.r is a pretty good example of dialecting!