Cheatsheet

Constructs

Construct name	Syntax	Semantics
Line comments	/text	Ignored by the parser
Inline & block comments	((text))	Ignored by the parser
Brackets	[code]	Like parenthesis
Definition	identifier: body	Defines a rule
Reference	ruleName	References / “calls” a named rule
Literal	"text" or 'text'	Matches exact text
Set	<characters>	Matches any single contained character
Sequences	rule1 rule2 ...	Matches several rules in order
Choice	rule1 | rule2 | ...*	Matches any of several rules
Optional	?rule	Optionally matches a rule
Oneplus	+rule	Matches a rule once or more
Zeroplus	*rule	Matches a rule zero or more times
Lambda	{rule}	Makes a new state for rule
Result	#rule	Sets the state to value from rule
Adjoinment	$rule	Appends text from rule to state
Property	key=rule	Maps key on state to value from rule
Extension	&rule	Appends a node to the state

* Leading and trailing pipes are allowed

Builtins

Name	Description or equivalent code
any	Matches any single character except \0
newline	+<\c\l>. Use in lieu of \n, which doesn’t exist.
whitespace	Matches any single whitespace character
_	*whitespace
lower	<abcdefghijklmnopqrstuvwxyz>
upper	<ABCDEFGHIJKLMNOPQRSTUVWXYZ>
alpha	lower | upper
digit	<1234567890>
alphanum	alpha | digit