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unprotect -- remove protection of identifiers

Introduction

unprotect(x) removes any write protection of the identifier x.

Call(s)

unprotect(x)

Parameters

x - an identifier

Returns

the previous protection level of x: either Error or Warning or None (see protect).

Related Functions

protect

Details

Example 1

unprotect allows to assign values to system functions:

>> unprotect(sign): sign(x) := 1
                                     1

However, we strongly advise not to change identifiers protected by the system. We undo the previous assignment:

>> delete sign(x): protect(sign, Error):

Example 2

unprotect does not evaluate its argument. Here the identifier x is unprotected and not its value y:

>> x := y:  protect(y): unprotect(x): y := 1
      Warning: protected variable y overwritten
      
                                     1
>> unprotect(y): delete x, y:

Changes




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