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tdefinitions.lisp - clic - Clic is an command line interactive client for gophe… |
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git clone git://bitreich.org/clic/ git://hg6vgqziawt5s4dj.onion/clic/ |
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tdefinitions.lisp (1656B) |
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1 (in-package :alexandria) |
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2 |
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3 (defun %reevaluate-constant (name value test) |
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4 (if (not (boundp name)) |
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5 value |
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6 (let ((old (symbol-value name)) |
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7 (new value)) |
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8 (if (not (constantp name)) |
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9 (prog1 new |
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10 (cerror "Try to redefine the variable as a constant." |
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11 "~@<~S is an already bound non-constant variable ~ |
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12 whose value is ~S.~:@>" name old)) |
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13 (if (funcall test old new) |
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14 old |
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15 (restart-case |
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16 (error "~@<~S is an already defined constant whose v… |
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17 ~S is not equal to the provided initial va… |
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18 under ~S.~:@>" name old new test) |
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19 (ignore () |
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20 :report "Retain the current value." |
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21 old) |
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22 (continue () |
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23 :report "Try to redefine the constant." |
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24 new))))))) |
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25 |
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26 (defmacro define-constant (name initial-value &key (test ''eql) document… |
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27 "Ensures that the global variable named by NAME is a constant with a v… |
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28 that is equal under TEST to the result of evaluating INITIAL-VALUE. TEST… |
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29 /function designator/ that defaults to EQL. If DOCUMENTATION is given, it |
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30 becomes the documentation string of the constant. |
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31 |
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32 Signals an error if NAME is already a bound non-constant variable. |
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33 |
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34 Signals an error if NAME is already a constant variable whose value is n… |
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35 equal under TEST to result of evaluating INITIAL-VALUE." |
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36 `(defconstant ,name (%reevaluate-constant ',name ,initial-value ,test) |
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37 ,@(when documentation `(,documentation)))) |
