(octave.info)Inline Functions

---

Prev: Anonymous Functions Up: Function Handles Anonymous Functions Inline Functions

---

Enter node , (file) or (file)node

11.11.3 Inline Functions
------------------------

An inline function is created from a string containing the function body
using the ‘inline’ function.  The following code defines the function
f(x) = x^2 + 2.

     f = inline ("x^2 + 2");

After this it is possible to evaluate f at any x by writing ‘f(x)’.

   *Caution*: MATLAB has begun the process of deprecating inline
functions.  At some point in the future support will be dropped and
eventually Octave will follow MATLAB and also remove inline functions.
Use anonymous functions in all new code.

 -- : inline (STR)
 -- : inline (STR, ARG1, ...)
 -- : inline (STR, N)
     Create an inline function from the character string STR.

     If called with a single argument, the arguments of the generated
     function are extracted from the function itself.  The generated
     function arguments will then be in alphabetical order.  It should
     be noted that i and j are ignored as arguments due to the ambiguity
     between their use as a variable or their use as an built-in
     constant.  All arguments followed by a parenthesis are considered
     to be functions.  If no arguments are found, a function taking a
     single argument named ‘x’ will be created.

     If the second and subsequent arguments are character strings, they
     are the names of the arguments of the function.

     If the second argument is an integer N, the arguments are "x",
     "P1", ..., "PN".

     Programming Note: The use of ‘inline’ is discouraged and it may be
     removed from a future version of Octave.  The preferred way to
     create functions from strings is through the use of anonymous
     functions (Note: Anonymous Functions) or ‘str2func’.

     See also: Note: argnames, Note: formula,
     Note: vectorize, Note: str2func.

 -- : argnames (FUN)
     Return a cell array of character strings containing the names of
     the arguments of the inline function FUN.

     See also: Note: inline, Note: formula,
     Note: vectorize.

 -- : formula (FUN)
     Return a character string representing the inline function FUN.

     Note that ‘char (FUN)’ is equivalent to ‘formula (FUN)’.

     See also: Note: char, Note: argnames, Note:
     inline, Note: vectorize.

 -- : VARS = symvar (STR)
     Identify the symbolic variable names in the string STR.

     Common constant names such as ‘i’, ‘j’, ‘pi’, ‘Inf’ and Octave
     functions such as ‘sin’ or ‘plot’ are ignored.

     Any names identified are returned in a cell array of strings.  The
     array is empty if no variables were found.

     Example:

          symvar ("x^2 + y^2 == 4")
          ⇒ {
               [1,1] = x
               [2,1] = y
             }