Compact Format (stream / lite / json / lua)

Since v4.0, non-atomic fields can declare cell format on the field name (not on ##type):

pos#format=lite
cost#format=json

Four formats

format	Meaning	Typical cell
stream (default)	Stream; blanks often skipped	With sep: 1,2,3
lite	Braces; usually no field names	{1.0,2.0,3.0}
json	JSON inside the cell	{"x":1,"y":2}
lua	Lua table inside the cell	{x=1,y=2}

Full lite example

<bean name="Vec3">
  <var name="x" type="float"/>
  <var name="y" type="float"/>
  <var name="z" type="float"/>
</bean>
<bean name="Shape"/>
<bean name="Circle" parent="Shape">
  <var name="radius" type="float"/>
</bean>

##var	id	pos#format=lite	shape#format=lite	tags#format=lite
##type	int	Vec3	Shape	list,int
	1	{1,2,3}	{Circle,1.5}	{10,20,30}
	2	{0,0,1}	{Circle,2.0}	{}

Key points:

Rule	Notes
bean / container	Use {...}; nesting allowed {1,xxxx,{1,2,3}}
Polymorphism	{TypeName,field1,field2,...}; when the type is Shape (not Shape?) you must give a concrete subclass; cannot write null
Nullable bean (T?)	Only then may you write null; do not write {null}
Defaults	Does not support column mode’s “omit field → use default”
Whitespace	Whitespace similar to HTML is stripped

json cell example

##var	id	pos#format=json	shape#format=json
##type	int	Vec3	Shape
	1	{"x":1,"y":2,"z":3}	{"$type":"Circle","radius":1.5}

Good when matching JSON fragments exported by external tools.

lua cell example

##var	id	pos#format=lua
##type	int	Vec3
	1	{x=1,y=2,z=3}

For polymorphic fields the type key is generally _type_ (same as file-based lua data sources).

Choosing among sep / column mode

Scenario	Suggestion
Designers want to read each column at a glance	Columns + merged cells
Short vectors, small structs	sep or lite
Existing JSON fragments	json
Very long lists that would explode columns	lite/json, or multi-row lists

Common pitfalls

• Putting #format=lite on ##type → no effect; put it on the field name.
• Writing {null} in lite for nullable → write null instead.
• Assuming lite can omit middle fields for defaults → it cannot; write them all or use column mode.

Related links

• Vertical tables and sep
• Other data sources (whole-file json/lua)
• Polymorphism