`fcnchk`

Turns a function name or expression into a callable function.

Category: Other public functions: funfun

Syntax

f = fcnchk(fun)

Returns fun unchanged if it is already a function handle, or builds a function from text.

Description

fcnchk was written so that older numerical routines could accept either a handle or a string. A function name such as 'sin' becomes a handle to that function. A string containing an expression is turned into a function of its free variable, x by default, so fcnchk('x^2+1') can be evaluated at any value.

New code should pass handles (@sin, @(x) x.^2 + 1) and skip this check.

Input arguments

fun: A function handle, a function name as text, or an expression in x as text such as 'x^2+1'.

Output arguments

f: Something that can be called with f(value).

Example

Handle or text

f = fcnchk(@sin);
f(0)
g = fcnchk('x^2+1');
g(2)

Output

ans = 0
ans = 5

Notes

MatLivre returns an inline function for text expressions, as older MATLAB releases do.

fcnchk