A Maple expression is syntactically valid as a unit name is a symbol, a symbol indexed by a symbol, or a function that is either of these whose arguments are symbols.

The type(expr, unit_name) function returns true if expr has the form of a syntactically valid unit name. Otherwise, false is returned.

This type exists mostly for use by the Units package internally; if you are considering using this in your program to test something related to user functionality, then it is almost certainly not what you want. Consider instead using the type with_unit to find expressions with units attached, or specfunc(Units:-Unit) to find Unit function calls.

$\mathrm{type}\left(\mathrm{meter}\,\mathrm{syntactically\_valid\_unit\_name}\right)$

$\mathrm{true}$

$\mathrm{type}\left(\mathrm{mile}\left[\mathrm{US\_survey}\right]\,\mathrm{syntactically\_valid\_unit\_name}\right)$

$\mathrm{true}$

$\mathrm{type}\left(\mathrm{meter}\left(\mathrm{radius}\right)\,\mathrm{syntactically\_valid\_unit\_name}\right)$

$\mathrm{true}$

$\mathrm{type}\left(\mathrm{foot}\left[\mathrm{standard}\right]\left(\mathrm{radius}\right)\,\mathrm{syntactically\_valid\_unit\_name}\right)$

$\mathrm{true}$

$\mathrm{type}\left(\mathrm{not\_an\_actual\_unit}\,\mathrm{syntactically\_valid\_unit\_name}\right)$

$\mathrm{true}$

$\mathrm{type}\left(\frac{m}{s}\,\mathrm{syntactically\_valid\_unit\_name}\right)$

$\mathrm{false}$