Format ideas

Variable/Result

[[var=expr]]
[[var=expr|'text']]
[[var=expr|'text',format]]

Number Box

[[var={}]]
[[var={val}]]

Adjustable Number

[[var=val,(min..max,step)]]
[[var=val,(min..max,step)|'text']]

Toggle

[[var=val|'text_0'|'text_1'|...]]

If/Switch

[[(cond_0?'text_0'),(cond_1?'text_1'),...]]

Graph

[[^(val1,val2,...)]]