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|
#lang racket/base
(require racket/contract
racket/format
racket/match
racket/port
(only-in xml xexpr->string)
(only-in "../find.rkt" find-signature)
"../scribble.rkt")
(provide type
describe)
(define (type v)
(type-or-sig v))
(define (type-or-sig v)
(or (type-or-contract v)
(sig v)
""))
(define (sig v) ;any/c -> (or/c #f string?)
(and (symbol? v)
(match (find-signature (symbol->string v))
[#f #f]
[x (~a x)])))
(define (type-or-contract v) ;any/c -> (or/c #f string?)
(or
;; 1. Try using Typed Racket's REPL simplified type.
(with-handlers ([exn:fail? (λ _ #f)])
(match (with-output-to-string
(λ ()
((current-eval)
(cons '#%top-interaction v))))
[(pregexp "^- : (.*) \\.\\.\\..*\n" (list _ t)) t]
[(pregexp "^- : (.*)\n$" (list _ t)) t]))
;; 2. Try to find a contract.
(with-handlers ([exn:fail? (λ _ #f)])
(parameterize ([error-display-handler (λ _ (void))])
((current-eval)
(cons '#%top-interaction
`(if (has-contract? ,v)
(~a (contract-name (value-contract ,v)))
(error ""))))))))
(define (sig-and/or-type stx)
(define dat (syntax->datum stx))
(define s (sig dat))
(define t (type-or-contract stx))
(xexpr->string
`(div ()
(h1 () ,(or s (~a dat)))
,(cond [(not (or s t))
`(p ()
(em () "(Found no documentation, signature, type, or contract.)"))]
[t `(pre () ,t)]
[else ""])
(br ()))))
;;; describe
;; If a symbol has installed documentation, display it.
;;
;; Otherwise, walk the source to find the signature of its definition
;; (because the argument names have explanatory value), and also look
;; for Typed Racket type or a contract, if any.
(define/contract (describe str)
(-> string? string?)
(define stx (namespace-symbol->identifier (string->symbol str)))
(or (scribble-doc/html stx)
(sig-and/or-type stx)))
|
