convert obsolete octave_fcn_inline object to @inline class Use a legacy @class object to provide inline function objects instead of using a built-in class derived from the octave_function_handle class. * scripts/legacy/@inline: New directory containing the following files: argnames.m, char.m, feval.m, formula.m, inline.m, subsref.m, vectorize.m. * scripts/legacy/@inline/module.mk: New file. * scripts/legacy/module.mk, scripts/module.mk: Update. * test/inline-fcn.tst: New tests. * test/module.mk: Update. * ov-fcn-inline.h, ov-fcn-inline.cc: Delete. Remove all uses. * libinterp/octave-value/module.mk: Update. * external.txi, func.txi, octave.texi, plot.txi, quad.txi: Eliminate discusion of inline function objects. * fplot.m, __ezplot__.m: Use isa to identify inline objects instead of instead of checking typeinfo. * ov-fcn-handle.cc, ov-typeinfo.cc: Fix tests. * ov-base.h, ov-base.cc (octave_base_value::fcn_inline_value): Delete. * ov.h, ov.cc (octave_value::fcn_inline_value): Delete. (octave_value::xfcn_inline_value): Delete value extractor. * ov-class.cc, ov-class.h (octave_inline, octave_inline_fcn): New classes that allow us to preserve the is_inline_function and function_value methods that were previously available in the octave_fcn_inline class. (F__inline_ctor__): New function for final construction of inline objects. * ls-hdf5.cc, ls-mat5.cc, ls-oct-binary.cc, ls-oct-text.cc: Handle loading of inline function objects from old files as special cases. New inline function objects will be saved and loaded as ordinary @class objects.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/inline-fcn.tst	Mon Mar 23 15:29:49 2020 -0400
@@ -0,0 +1,33 @@
+## INLINE contstructor
+
+%!shared fn
+%! fn = inline ("x.^2 + 1");
+%!assert (feval (fn, 6), 37)
+%!assert (fn (6), 37)
+%!assert (feval (inline ("sum (x(:))"), [1 2; 3 4]), 10)
+%!assert (feval (inline ("sqrt (x^2 + y^2)", "x", "y"), 3, 4), 5)
+%!assert (feval (inline ("exp (P1*x) + P2", 3), 3, 4, 5), exp(3*4) + 5)
+
+## Test input validation
+%!error inline ()
+%!error <EXPR must be a string> inline (1)
+%!error <N must be an integer> inline ("2", ones (2,2))
+%!error <N must be a positive integer> inline ("2", -1)
+%!error <additional arguments must be strings> inline ("2", "x", -1, "y")
+
+## FORMULA
+
+%!assert (formula (fn), "x.^2 + 1")
+%!assert (formula (fn), char (fn))
+
+## ARGNAMES
+
+%!assert (argnames (fn), {"x"})
+%!assert (argnames (inline ("1e-3*y + 2e4*z")), {"y"; "z"})
+%!assert (argnames (inline ("2", 2)), {"x"; "P1"; "P2"})
+
+## VECTORIZE
+
+%!assert (formula (vectorize (fn)), "x.^2 + 1")
+%!assert (formula (vectorize (inline ("1e-3*y + 2e4*z"))), "1e-3.*y + 2e4.*z")
+%!assert (formula (vectorize (inline ("2**x^5"))), "2.**x.^5")