dd1ea541ec
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
[ Nothing here at this time. ]