- Add nasal::String for wrapping Nasal string data and accessing
string methods (which eg. could be exposed to Nasal)
- Allow adding functions from C/C++ which are callable on
Nasal strings.
so hopefully not too much breaks). New syntax features:
1. Call-by-name function arguments. You can specify a hash literal in
place of ordered function arguments, and it will become the local
variable namespace for the called function, making functions with many
arguments more readable. Ex:
view_manager.lookat(heading:180, pitch:20, roll:0, x:X0, y:Y0, z:Z0,
time:now, fov:55);
Declared arguments are checked and defaulted as would be expected:
it's an error if you fail to pass a value for an undefaulted argument,
missing default arguments get assigned, and any rest parameter
(e.g. "func(a,b=2,rest...){}") will be assigned with an empty vector.
2. Vector slicing. Vectors (lists) can now be created from others
using an ordered list of indexes and ranges. For example:
var v1 = ["a","b","c","d","e"]
var v2 = v1[3,2]; # == ["d","c"];
var v3 = v1[1:3]; # i.e. range from 1 to 3: ["b","c","d"];
var v4 = v1[1:]; # no value means "to the end": ["b","c","d","e"]
var i = 2;
var v5 = v1[i]; # runtime expressions are fine: ["c"]
var v6 = v1[-2,-1]; # negative indexes are relative to end: ["d","e"]
The range values can be computed at runtime (e.g. i=1; v5=v1[i:]).
Negative indices work the same way the do with the vector functions
(-1 is the last element, -2 is 2nd to last, etc...).
3. Multi-assignment expressions. You can assign more than one
variable (or lvalue) at a time by putting them in a parenthesized
list:
(var a, var b) = (1, 2);
var (a, b) = (1, 2); # Shorthand for (var a, var b)
(var a, v[0], obj.field) = (1,2,3) # Any assignable lvalue works
var color = [1, 1, 0.5];
var (r, g, b) = color; # works with runtime vectors too
Nasal now supports calls to "subcontexts" and errors can be thrown
across them, leading to complete stack traces when call() is used,
instead of the truncated ones we now see.
Vectors can now be concatenated using the ~ operator that used to work
only for strings.
Better runtime error messages in general due to a fancier
naRuntimeError() implementation
A big data size shrink on 64 bit systems; the size of a naRef dropped
by a factor of two.
"Braceless code blocks" have been added to the parser, so you can
write expressions like "if(a) b();" just like in C. Note that there's
still a parser bug in there that fails when you nest a braced block
within a braceless one.
Character constants that appear in Nasal source code can now be
literal multibyte UTF8 characters (this was always supported for
string literals, but character constants were forced to be a single
byte).
New modules: "bits", "thread", "utf8" and (gulp...) "io". The bits
library might be useful to FlightGear, the utf8 one probably not as
Plib does not support wide character text rendering. The thread
library will work fine for spawning threads to do Nasal stuff, but
obviously contact with the rest of FlightGear must be
hand-synchronized as FlightGear isn't threadsafe. The io library is
no doubt the most useful, as it exposes all the basic stdio.h
facilities; it's also frighteningly dangerous when combined with
networked code...
*appears* to work correctly on all systems to which I have access
(i386 linux/win32, x86_64 linux, powerpc OS X, Sparc Solaris 10), but
not all systems are capable of running fgfs. Beyond that, multiple
threading bugs were fixed, and the naCall() API changed slightly to
support named function arguments.
NOTE: this introduces a change in the external API, and therefore this
change *must* be compiled against current FlightGear code.
code generation of constant objects to use real identity and not Nasal
equality, so (e.g.) the constants 1 (number) and "1.0" (string) do not
get turned into the same object in the generated code.
