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#lang racket/base
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(require (for-syntax racket/base racket/syntax))
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(require net/url xml racket/set)
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(require "../len.rkt" "../define/provide.rkt")
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(define (make-coercion-error-handler target-format x)
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(λ(e) (error (format "Can’t convert ~a to ~a" x target-format))))
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(define+provide (->int x)
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(with-handlers ([exn:fail? (make-coercion-error-handler 'integer x)])
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(cond
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[(or (integer? x) (real? x)) (inexact->exact (floor x))]
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[(and (string? x) (> (len x) 0)) (->int (string->number x))]
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[(symbol? x) (->int (->string x))]
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[(char? x) (char->integer x)]
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[else (len x)])))
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(define+provide (->string x)
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(if (string? x)
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x ; fast exit for strings
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(with-handlers ([exn:fail? (make-coercion-error-handler 'string x)])
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(cond
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[(equal? '() x) ""]
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[(symbol? x) (symbol->string x)]
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[(number? x) (number->string x)]
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[(path? x) (path->string x)]
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[(char? x) (format "~a" x)]
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[else (error)]))))
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(define+provide (->symbol x)
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(if (symbol? x)
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x
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(with-handlers ([exn:fail? (make-coercion-error-handler 'symbol x)])
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(string->symbol (->string x)))))
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(define+provide (->path x)
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(if (path? x)
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x
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(with-handlers ([exn:fail? (make-coercion-error-handler 'path x)])
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(cond
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[(url? x) (apply build-path (map path/param-path (url-path x)))]
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[else (string->path (->string x))]))))
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(define+provide (->url x)
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(with-handlers ([exn:fail? (make-coercion-error-handler 'url x)])
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(string->url (->string x))))
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(define+provide (->complete-path x)
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(with-handlers ([exn:fail? (make-coercion-error-handler 'complete-path x)])
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(path->complete-path (->path x))))
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(define+provide (->list x)
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(if (list? x)
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x
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(with-handlers ([exn:fail? (make-coercion-error-handler 'list x)])
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(cond
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[(vector? x) (vector->list x)]
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[(set? x) (set->list x)]
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[else (list x)]))))
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(define+provide (->vector x)
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(if (vector? x)
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x
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(with-handlers ([exn:fail? (make-coercion-error-handler 'vector x)])
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(list->vector (->list x)))))
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(define+provide (->boolean x)
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(and x #t))
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(define-syntax (make-*ish-predicate stx)
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(syntax-case stx ()
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[(_ stem)
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(with-syntax ([stemish? (format-id stx "~aish?" #'stem)]
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[->stem (format-id stx "->~a" #'stem)])
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#`(begin
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(define+provide (stemish? x)
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(with-handlers ([exn:fail? (λ(e) #f)]) (and (->stem x) #t)))))]))
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(make-*ish-predicate int)
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(make-*ish-predicate string)
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(make-*ish-predicate symbol)
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(make-*ish-predicate url)
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(make-*ish-predicate complete-path)
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(make-*ish-predicate path)
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;; no point to having list and vector here; they work with everything
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