Update packages

elpa/racket-mode-20181004.309/racket/commands/describe.rkt

@@ -0,0 +1,73 @@
+#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)))