#lang racket/base (require (for-syntax racket/base racket/syntax)) (require racket/contract "../define/provide.rkt" "value.rkt") (define-syntax-rule (make-blame-handler try-proc expected-sym) (λ(b) (λ(x) (with-handlers ([exn:fail? (λ(e) (raise-blame-error b x '(expected: "~a" given: "~e") expected-sym x))]) (try-proc x))))) (provide make-coercion-contract) (define-syntax (make-coercion-contract stx) (syntax-case stx () [(_ stem) (let ([stem-datum (syntax->datum #'stem)]) (with-syntax ([coerce/stem? (format-id stx "coerce/~a?" #'stem)] [->stem (format-id stx "->~a" #'stem)] [can-be-stem? (format-id stx "can-be-~a?" #'stem)]) #'(define+provide coerce/stem? (make-contract #:name 'coerce/stem? #:projection (make-blame-handler ->stem 'can-be-stem?)))))])) (make-coercion-contract int) (make-coercion-contract string) (make-coercion-contract symbol) (make-coercion-contract path) (make-coercion-contract boolean) #| (define/contract (foo x) (coerce/string? . -> . any/c) x)|#