procedure (format-id   lctx             fmt             v ...            [ #:source src             #:props props             #:cert ignored])   →   identifier?

lctx : (or/c syntax? #f)

fmt : string?

v : (or/c string? symbol? identifier? keyword? char? number?)

src : (or/c syntax? #f) = #f

props : (or/c syntax? #f) = #f

ignored : (or/c syntax? #f) = #f

> (define-syntax (make-pred stx)     (syntax-case stx ()       [(make-pred name)        (format-id #'name "~a?" (syntax-e #'name))]))

> (make-pred pair)

#<procedure:pair?>

> (make-pred none-such)

none-such?: undefined;

cannot reference an identifier before its definition

in module: top-level

> (define-syntax (better-make-pred stx)     (syntax-case stx ()       [(better-make-pred name)        (format-id #'name #:source #'name                   "~a?" (syntax-e #'name))]))

> (better-make-pred none-such)

none-such?: undefined;

cannot reference an identifier before its definition

in module: top-level

procedure (format-symbol fmt v ...) → symbol?

fmt : string?

v : (or/c string? symbol? identifier? keyword? char? number?)

> (format-symbol "make-~a" 'triple)

'make-triple

syntax (define/with-syntax pattern stx-expr)

stx-expr   :   syntax?

> (define/with-syntax (px ...) #'(a b c))

> (define/with-syntax (tmp ...) (generate-temporaries #'(px ...)))

> #'([tmp px] ...)

#<syntax:eval:11:0 ((a9 a) (b10 b) (c11 c))>

> (define/with-syntax name #'Alice)

> #'(hello name)

#<syntax:eval:13:0 (hello Alice)>

parameter (current-syntax-context) → (or/c syntax? false/c)

(current-syntax-context stx) → void?

stx : (or/c syntax? false/c)

procedure (wrong-syntax stx format-string v ...) → any

stx : syntax?

format-string : string?

v : any/c

> (wrong-syntax #'here "expected ~s" 'there)

eval:14:0: ?: expected there

at: here

> (parameterize ([current-syntax-context #'(look over here)])     (wrong-syntax #'here "expected ~s" 'there))

eval:15:0: look: expected there

at: here

in: (look over here)

(define-syntax (my-macro stx)

(parameterize ([current-syntax-context stx])

(syntax-case stx ()

__)))

parameter (current-recorded-disappeared-uses)

→ (or/c (listof identifier?) false/c)

(current-recorded-disappeared-uses ids) → void?

ids : (or/c (listof identifier?) false/c)

syntax (with-disappeared-uses body-expr ... stx-expr)

stx-expr   :   syntax?

procedure (syntax-local-value/record id predicate) → any/c

id : identifier?

predicate : (-> any/c boolean?)

procedure (record-disappeared-uses id [intro?]) → void?

id : (or/c identifier? (listof identifier?))

intro? : boolean? = (syntax-transforming?)

procedure (generate-temporary [name-base]) → identifier?

name-base : any/c = 'g

procedure (internal-definition-context-apply   intdef-ctx             stx)   →   syntax?

intdef-ctx : internal-definition-context?

stx : syntax?

procedure (syntax-local-eval stx [intdef-ctx]) → any

stx : syntax?

intdef-ctx   :   (or/c internal-definition-context?       (listof internal-definition-context?)       #f)   =   '()

> (define-syntax (show-me stx)     (syntax-case stx ()       [(show-me expr)        (begin          (printf "at compile time produces ~s\n"                  (syntax-local-eval #'expr))          #'(printf "at run time produces ~s\n"                    expr))]))

> (show-me (+ 2 5))

at compile time produces 7 at run time produces 7

> (define-for-syntax fruit 'apple)

> (define fruit 'pear)

> (show-me fruit)

at compile time produces apple at run time produces pear

syntax (with-syntax* ([pattern stx-expr] ...)   body ...+)

stx-expr   :   syntax?

> (with-syntax* ([(x y) (list #'val1 #'val2)]                  [nest #'((x) (y))])     #'nest)

#<syntax:eval:21:0 ((val1) (val2))>