Re: Caching of Template Instantiations
On Saturday, 17 October 2015 at 07:48:39 UTC, Nordlöw wrote:
Does DMD cache template instantiations?
Yes, and it's required by the spec:
"Multiple instantiations of a TemplateDeclaration with the same
TemplateArgumentList all will refer to the same instantiation."
http://dlang.org/template.html
That is, is it preferred to do, for instance, either
static if (isIntegral!T && isUnsigned!(T)) {}
else static if (isIntegral!T && isSigned!(T)) {}
or
enum integral = isIntegral!T;
static if (integral && isUnsigned!(T)) {}
else static if (integral && isSigned!(T)) {}
It *might* make a little difference if you have thousands of
instantiations, because for each instantiation the compiler needs
to check whether it has already instantiated the templation with
that combination of arguments, but I wouldn't worry about it.
Caching of Template Instantiations
Does DMD cache template instantiations?
That is, is it preferred to do, for instance, either
static if (isIntegral!T && isUnsigned!(T)) {}
else static if (isIntegral!T && isSigned!(T)) {}
or
enum integral = isIntegral!T;
static if (integral && isUnsigned!(T)) {}
else static if (integral && isSigned!(T)) {}
what is wrong with this code??
import std.string, std.typecons, std.exception,
std.algorithm,std.stdio;
import std.traits: hasIndirections;
struct GrowableCircularQueue(T) {
public size_t length;
private size_t first, last;
private T[] A = [T.init];
this(T[] items...) pure nothrow @safe {
foreach (x; items)
push(x);
}
@property bool empty() const pure nothrow @safe @nogc {
return length == 0;
}
@property T front() pure nothrow @safe @nogc {
assert(length != 0);
return A[first];
}
T opIndex(in size_t i) pure nothrow @safe @nogc {
assert(i < length);
return A[(first + i) & (A.length - 1)];
}
void push(T item) pure nothrow @safe {
if (length >= A.length) { // Double the queue.
immutable oldALen = A.length;
A.length *= 2;
if (last < first) {
A[oldALen .. oldALen + last + 1] = A[0 .. last +
1];
static if (hasIndirections!T)
A[0 .. last + 1] = T.init; // Help for the GC.
last += oldALen;
}
}
last = (last + 1) & (A.length - 1);
A[last] = item;
length++;
}
@property T pop() pure nothrow @safe @nogc {
assert(length != 0);
auto saved = A[first];
static if (hasIndirections!T)
A[first] = T.init; // Help for the GC.
first = (first + 1) & (A.length - 1);
length--;
return saved;
}
}
const struct Board {
private enum El { floor = ' ', wall = '#', goal = '.',
box = '$', player = '@', boxOnGoal='*' }
private alias CTable = string;
private immutable size_t ncols;
private immutable CTable sData, dData;
private immutable int playerx, playery;
this(in string[] board) immutable
in {
foreach (const row; board) {
assert(row.length == board[0].length,
"Unequal board rows.");
foreach (immutable c; row)
assert(c.inPattern(" #.$@*"), "Not valid input");
}
} body {
/*static*/ immutable sMap =
[' ':' ', '.':'.', '@':' ', '#':'#', '$':' '];
/*static*/ immutable dMap =
[' ':' ', '.':' ', '@':'@', '#':' ', '$':'*'];
ncols = board[0].length;
writeln("ncols =",ncols);
int plx = 0, ply = 0;
CTable sDataBuild, dDataBuild;
foreach (immutable r, const row; board)
foreach (immutable c, const ch; row) {
sDataBuild ~= sMap[ch];
dDataBuild ~= dMap[ch];
if (ch == El.player) {
plx = c;
ply = r;
}
// writeln("c ch row ",c," ",ch," ",row);
// writeln("board =>",board);
}
this.sData = sDataBuild;
this.dData = dDataBuild;
this.playerx = plx;
this.playery = ply;
}
private bool move(in int x, in int y, in int dx,
in int dy, ref CTable data)
const pure nothrow /*@safe*/ {
if (sData[(y + dy) * ncols + x + dx] == El.wall ||
data[(y + dy) * ncols + x + dx] != El.floor)
return false;
auto data2 = data.dup;
data2[y * ncols + x] = El.floor;
data2[(y + dy) * ncols + x + dx] = El.player;
data = data2.assumeUnique; // Not enforced.
return true;
}
private bool push(in int x, in int y, in int dx,
in int dy, ref CTable data)
const pure nothrow /*@safe*/ {
if (sData[(y + 2 * dy) * ncols + x + 2 * dx] == El.wall ||
data[(y + 2 * dy) * ncols + x + 2 * dx] != El.floor)
return false;
auto data2 = data.dup;
data2[y * ncols + x] = El.floor;
data2[(y + dy) * ncols + x + dx] = El.player;
data2[(y + 2 * dy) * ncols + x + 2*dx] = El.boxOnGoal;
data = data2.assumeUnique; // Not enforced.
return true;
}
private bool isSolved(in CTable data)
const pure nothrow @safe @nogc {
foreach (immutable i, immutable d; data)
if ((sData[i] == El.goal) != (d == El.boxOnGoal))
return false;
return true;
}
string solve() pure nothrow /*@safe*/ {
bool[immutable CTable] visitedSet = [dData: true];
alias Four = Tuple!(CTable, string, int, int);
GrowableCircularQueue!Four open;
open.push(Four(dData, "", playerx, playery));
static immutable dirs = [tuple( 0, -1, 'u', 'U'),
tuple( 1, 0, 'r', 'R'),
tuple( 0, 1, 'd', 'D'),
tuple(-1, 0, 'l', 'L')];
while (!open.empty) {
//immutable (cur, cSol, x, y) = open.pop;
immutable item = open.pop;
immutable cur = item[0];
immutable cSol = item[1];
immutable x =
Re: LuaD: creating a flexible data filter system
On Saturday, 17 October 2015 at 02:02:16 UTC, Jakob Ovrum wrote: On Friday, 16 October 2015 at 10:45:52 UTC, Chris wrote: Later you call the function with the Lua C API like "lua_pcall(L, 0, 1, 0);". It's a bit tricky to move things around on the Lua stack, but you'll get there! ;) Or you could use LuaD which doesn't require you to mess around with the relatively unproductive, bug-prone C API :) I've used both, LuaD and DerelictLua + my own smaller D library that wraps all these nasty Lua stack operations (e.g. creating, accessing and adding to tables). The better I got to know the Lua C API while writing my own wrappers, the more I came to appreciate LuaD :-) However, LuaD is still 5.1 and I didn't want to be stuck with 5.1. So I rolled my own. It's not as comprehensive as LuaD but did the trick. The purpose was to experiment with Lua server pages + vibe.d which worked fine. Rikki gave me the idea to compile each page as a Lua function into memory for faster execution (etLua style[1]). It works fine with both LuaD and my own wrappers. In my own version I use the Lua C API directly in some places, though I don't know, if that's really a big speedup. If I set up my own homepage, I'd probably give vibe.d + Lua a shot. No more PHP and sh*t like that. [1] https://github.com/leafo/etlua
Re: LuaD: creating a flexible data filter system
many thanks for the valuable insights. so far i made a simple prototype with LuaD and classes, works nicely for when my niput what so far is not 100% clear is if there is a way to have a parsed msgpack or json documents being exposed in my lua code in a way so it behaves like a lua object. Ideally in a RW fashion so that changed then again can be processed by D code.
Re: OT: why do people use python when it is slow?
On Wednesday, 14 October 2015 at 18:17:29 UTC, Russel Winder wrote: On Wed, 2015-10-14 at 14:48 +, John Colvin via Digitalmars-d-learn wrote: On Wednesday, 14 October 2015 at 14:32:00 UTC, jmh530 wrote: > On Tuesday, 13 October 2015 at 23:26:14 UTC, Laeeth Isharc > wrote: > > https://www.quora.com/Why-is-Python-so-popular-despite-being-so-s > > low > > Andrei suggested posting more widely. > > I was just writing some R code yesterday after playing > around with D for a couple weeks. I accomplished more in an > afternoon of R coding than I think I had in like a month's > worth of playing around with D. The same is true for python. As someone who uses both D and Python every day, I find that - once you are proficient in both - initial productivity is higher in Python and then D starts to overtake as a project gets larger and/or has stricter requirements. I hope never to have to write anything longer than a thousand lines in Python ever again. The thing about Python is NumPy, SciPy, Pandas, Matplotlib, IPython, Jupyter, GNU Radio. The data science, bioinformatics, quant, signal provessing, etc. people do not give a sh!t which language they used, what they want is to get their results as fast as possible. Most of them do not write programs that are to last, they are effectively throw away programs. This leads them to Python (or R) and they are not really interested in learning anything else. The fact that NumPy sort of sucks in terms of performance, isn't noticed by them as they get their results "fast enough" and a lot faster than sequential Python. The fact that if they used Chapel or even D for their compute intensive code they would rapidly discover that NumPy sort of sucks never really occurs to these people as they are focussed on the results not the means of achieving them. Polyglot Python/D or Python/Chapel with Matplotlib is the way to go. But that really requires a D replacement for Pandas. Russell, thanks for your thoughts - I appreciate it. What would a Pandas replacement look like in D?
Re: LuaD: creating a flexible data filter system
On Saturday, 17 October 2015 at 13:15:17 UTC, yawniek wrote: many thanks for the valuable insights. so far i made a simple prototype with LuaD and classes, works nicely for when my niput what so far is not 100% clear is if there is a way to have a parsed msgpack or json documents being exposed in my lua code in a way so it behaves like a lua object. Ideally in a RW fashion so that changed then again can be processed by D code. http://luajit.org/ext_ffi_tutorial.html C meta methods
Re: what is wrong with this code??
On Saturday, October 17, 2015 04:17 PM, steven kladitis wrote: > // it thows a range exception On which line?
Re: what is wrong with this code??
On Saturday, October 17, 2015 04:50 PM, steven kladitis wrote: > core.exception.RangeError@sokuban.d(84): Range violation Line 84 being this: sDataBuild ~= sMap[ch]; Where sMap is: /*static*/ immutable sMap = [' ':' ', '.':'.', '@':' ', '#':'#', '$':' ']; Apparently, ch is some char that's not a key in sMap. Try printing out ch to see what it is exactly. Then, assuming it's really not a key in sMap, figure out if sMap should have that key, or if ch should not end up with that value.
Compiling a .d file both as library and executable
In Python there is: if __name__ == "__main__": to allow the same source file to be treated as both an importable library and as an executable script. In D is there any such mechanism to make a main() compiled selectively, i.e. by some compile-time flag or such? -- Shriramana Sharma, Penguin #395953
Re: what is wrong with this code??
On Saturday, 17 October 2015 at 14:47:11 UTC, anonymous wrote: On Saturday, October 17, 2015 04:17 PM, steven kladitis wrote: // it thows a range exception On which line? core.exception.RangeError@sokuban.d(84): Range violation
Re: what is wrong with this code??
On Saturday, 17 October 2015 at 14:59:41 UTC, anonymous wrote: On Saturday, October 17, 2015 04:50 PM, steven kladitis wrote: core.exception.RangeError@sokuban.d(84): Range violation Line 84 being this: sDataBuild ~= sMap[ch]; Where sMap is: /*static*/ immutable sMap = [' ':' ', '.':'.', '@':' ', '#':'#', '$':' ']; Apparently, ch is some char that's not a key in sMap. Try printing out ch to see what it is exactly. Then, assuming it's really not a key in sMap, figure out if sMap should have that key, or if ch should not end up with that value. Yes!!! Now it makes sense!!! Thanks
Re: Compiling a .d file both as library and executable
On Saturday, October 17, 2015 05:36 PM, Shriramana Sharma wrote: > In Python there is: > > if __name__ == "__main__": > > to allow the same source file to be treated as both an importable library > and as an executable script. In D is there any such mechanism to make a > main() compiled selectively, i.e. by some compile-time flag or such? > http://stackoverflow.com/questions/18537761/hyrbid-modul-and-program-behaviour-for-a-d-source-file
