5 Advanced Student

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5 Advanced Student

The grammar notation uses the notation X ... (bold dots) to indicate that X may occur an arbitrary number of times (zero, one, or more). Separately, the grammar also defines ... as an identifier to be used in templates.

program

def-or-expr ...

def-or-expr

definition

expr

test-case

library-require

definition

(define (name variable ...) expr)

(define name expr)

(define-struct name (name ...))

(define-datatype name (name name ...) ...)

expr

(begin expr expr ...)

(begin0 expr expr ...)

(set! variable expr)

(delay expr)

(lambda (variable ...) expr)

(λ (variable ...) expr)

(local [definition ...] expr)

(letrec ([name expr] ...) expr)

(shared ([name expr] ...) expr)

(let ([name expr] ...) expr)

(let name ([name expr] ...) expr)

(let* ([name expr] ...) expr)

(recur name ([name expr] ...) expr)

(expr expr ...)

(cond [expr expr] ... [expr expr])

(cond [expr expr] ... [else expr])

(case expr [(choice choice ...) expr] ...

[(choice choice ...) expr])

(case expr [(choice choice ...) expr] ...

[else expr])

(match expr [pattern expr] ...)

(if expr expr expr)

(when expr expr)

(unless expr expr)

(and expr expr expr ...)

(or expr expr expr ...)

(time expr)

name

’quoted

‘quasiquoted

’()

number

boolean

string

character

choice

name

number

pattern

name

number

true

false

string

character

’quoted

‘quasiquoted-pattern

(cons pattern pattern)

(list pattern ...)

(list* pattern ...)

(struct id (pattern ...))

(vector pattern ...)

(box pattern)

quasiquoted-pattern

name

number

string

character

(quasiquoted-pattern ...)

’quasiquoted-pattern

‘quasiquoted-pattern

,pattern

,@pattern

quoted

name

number

string

character

(quoted ...)

’quoted

‘quoted

,quoted

,@quoted

quasiquoted

name

number

string

character

(quasiquoted ...)

’quasiquoted

‘quasiquoted

,expr

,@expr

test-case

(check-expect expr expr)

(check-random expr expr)

(check-within expr expr expr)

(check-error expr expr ...)

(check-member-of expr expr expr)

(check-satisfied expr expr)

(check-range expr expr)

(check-range expr)

library-require

(require string)

(require (lib string string ...))

(require (planet string package))

package

(string string number number)

A name or a variable is a sequence of characters not including a space or one of the following:

" , ' ` ( ) [ ] { } | ; #

A number is a number such as 123, 3/2, or 5.5.

A boolean is one of: #true or #false. Alternative spellings for the #true constant are #t, true, and #T. Similarly, #f, false, or #F are also recognized as #false.

A symbol is a quote character followed by a name. A symbol is a value, just like 42, '(), or #false.

A string is a sequence of characters enclosed by a pair of ". Unlike symbols, strings may be split into characters and manipulated by a variety of functions. For example, "abcdef", "This is a string", and "This is a string with \" inside" are all strings.

A character begins with #\ and has the name of the character. For example, #\a, #\b, and #\space are characters.

In function calls, the function appearing immediately after the open parenthesis can be any functions defined with define or define-struct, or any one of the pre-defined functions.

5.1 Pre-defined Variables

value
empty : empty?

The empty list.

value
true : boolean?

The #true value.

value
false : boolean?

The #false value.