Preventing evaluation

### 9.1.4 Preventing evaluation

You can prevent an expression from being evaluated by quoting it, either by preceding it with ’ or with the quote or hold) command.

##### Remark.

If a is a variable, then a:=quote(a) (or a:=hold(a)) is equivalent to purge(a) (for the sake of Maple compatibility). It returns the value of this variable (or the hypothesis done on this variable).

#### Example

a:=2; quote(2+3*a)

or:

a:=2;'2+3*a'

2,2+3 a |  |  |  |  |  |  |  |  |  |