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Std/io

Read-file-as-string

Signature
(read-file-as-string filename state) → (mv contents/nil state)
Arguments: filename — Guard (stringp filename).
Returns: contents/nil — On success: the entire contents of the file as an ordinary string. On failure, e.g., because filename does not exist: nil.
Type (or (stringp contents/nil) (not contents/nil)).

This is just a wrapper around read-file-characters. We leave it enabled.

Definitions and Theorems

Function: read-file-as-string

(defun read-file-as-string (filename state)
  (declare (xargs :stobjs (state)))
  (declare (xargs :guard (stringp filename)))
  (let ((__function__ 'read-file-as-string))
    (declare (ignorable __function__))
    (mbe :logic
         (b* (((mv chars state)
               (read-file-characters filename state)))
           (mv (and (not (stringp chars))
                    (implode chars))
               state))
         :exec
         (b* (((mv rchars state)
               (read-file-characters-rev filename state)))
           (mv (and (not (stringp rchars))
                    (str::rchars-to-string rchars))
               state)))))

Theorem: return-type-of-read-file-as-string.contents/nil

(defthm return-type-of-read-file-as-string.contents/nil
  (b* (((mv ?contents/nil ?state)
        (read-file-as-string filename state)))
    (or (stringp contents/nil)
        (not contents/nil)))
  :rule-classes :type-prescription)