(require mzlib/match)

The mzlib/match library provides a match form similar to that of scheme/match, but with an different (older and less extensible) syntax of patterns.

(match val-expr clause ...)

clause   =   [pat expr ...+]     |   [pat (=> id) expr ...+]

See match from scheme/match for a description of matching. The grammar of pat for this match is as follows:

pat		::=		id		match anything, bind identifier
		|		_		match anything
		|		literal		match literal
		|		'datum		match equal? datum
		|		(lvp ...)		match sequence of lvps
		|		(lvp ... . pat)		match lvps consed onto a pat
		|		#(lvp ...)		match vector of pats
		|		#&pat		match boxed pat
		|		($ struct-id pat ...)		match struct-id instance
		|		(and pat ...)		match when all pats match
		|		(or pat ...)		match when any pat match
		|		(not pat ...)		match when no pat match
		|		(= expr pat)		match (expr value) to pat
		|		(? pred-expr pat ...)		match if (expr value) and pats
		|		`qp		match quasipattern
literal		::=		#t		match true
		|		#f		match false
		|		string		match equal? string
		|		number		match equal? number
		|		character		match equal? character
		|		bytes		match equal? byte string
		|		keyword		match equal? keyword
		|		regexp		match equal? regexp literal
		|		pregexp		match equal? pregexp literal
lvp		::=		pat		greedily match pat instances
		|		pat		match pat
ooo		::=		...		zero or more; ... is literal
		|		___		zero or more
		|		..k		k or more
		|		__k		k or more
qp		::=		literal		match literal
		|		id		match equal? symbol
		|		(qp ...)		match sequences of qps
		|		(qp ... . qp)		match sequence of qps consed onto a qp
		|		(qp ... qp ooo)		match qps consed onto a repeated qp
		|		#(qp ...)		match vector of qps
		|		#&qp		match boxed qp
		|		,pat		match pat
		|		,@pat		match pat, spliced

(match-lambda clause ...)

(match-lambda* clause ...)

(match-let ([pat expr] ...) body ...+)

(match-let* ([pat expr] ...) body ...+)

(match-letrec ([pat expr] ...) body ...+)

(match-define pat expr)

Analogous to the combined forms from scheme/match.

(define-match-expander id proc-expr) (define-match-expander id proc-expr proc-expr) (define-match-expander id proc-expr proc-expr proc-expr)

(match-equality-test) → (any/c any/c . -> . any) (match-equality-test comp-proc) → void?   comp-proc : (any/c any/c . -> . any)

Analogous to the form and parameter from scheme/match. The define-match-expander form, however, supports an extra proc-expr as the middle one: an expander for use with match from mzlib/match.