Re: How to escape control characters?
On Tuesday, 23 August 2022 at 13:09:01 UTC, Steven Schveighoffer
wrote:
Without allocations. This took me longer than I had hoped it
would. It needs the 1-char buffer to avoid sending the
surrounding quotes.
Surely what Steve does is better. But for some reason I like
simple and useful things.
I sometimes use custom string wrapping. Maybe it will be useful
for you, for example:
```d
struct String {
string str;
alias str this;
import std.format, std.string;
void toString(scope void delegate(const(char)[]) sink,
FormatSpec!char fmt)const
{
auto arr = str.lineSplitter;
if(fmt.spec == 'n') {
sink.formattedWrite("%-(%s\\n%)", arr);
} else sink.formattedWrite("%s", str);
}
} unittest {
import std.stdio;
auto str = `this
is a
string`;
String Str; // simple constructor
Str = str; // direct assign
Str.writefln!"%n"; // "this\n is a\n string"
Str.writefln!"%s"; /*
this
is a
string
*/
}
```
The nice thing here is that you can change the format specifiers
as you wish.
Thank you all...
SDB@79
Re: what's this error: allocatestack.c:384: advise_stack_range: Assertion `freesize < size' failed.
On Tuesday, 23 August 2022 at 18:50:14 UTC, mw wrote: Hi, I got an error message when my program exits (the main functionality is done, I guess the error happened during D runtime's cleanup) : allocatestack.c:384: advise_stack_range: Assertion `freesize < size' failed. I suspect it somehow related to I pass some (object) pointers to foreign languages containers (C and Rust). But my main program seems behave correctly (I keep those pointers on the D side to prevent them from being GC-ed), this error only happens when the program exits. Anyone can give me some hint where I should look at? (and where is the allocatestack.c?) Thanks. allocatestack.c is some thing of GLIBC, the line seems to match [1] but I don't think that will help you much. You will need to get a trace where the function is called. [1] https://code.woboq.org/userspace/glibc/nptl/allocatestack.c.html
what's this error: allocatestack.c:384: advise_stack_range: Assertion `freesize < size' failed.
Hi, I got an error message when my program exits (the main functionality is done, I guess the error happened during D runtime's cleanup) : allocatestack.c:384: advise_stack_range: Assertion `freesize < size' failed. I suspect it somehow related to I pass some (object) pointers to foreign languages containers (C and Rust). But my main program seems behave correctly (I keep those pointers on the D side to prevent them from being GC-ed), this error only happens when the program exits. Anyone can give me some hint where I should look at? (and where is the allocatestack.c?) Thanks.
Re: How to escape control characters?
On 8/23/22 6:09 AM, Bastiaan Veelo wrote:
On Thursday, 31 March 2016 at 03:15:49 UTC, cy wrote:
This might be a dumb question. How do I format a string so that all
the newlines print as \n and all the tabs as \t and such?
The easiest is this:
```d
import std.conv;
string str = `Hello "World"
line 2`;
writeln([str].text[2..$-2]); // Hello \"World\"\nline 2
```
I know this is an old post, but I felt this trick needed to be shared.
This takes advantage of the fact that `std.format` escapes the
characters in an array of strings. So we create an array where `str` is
the only element, and convert that to text. Without the `[2..$-2]`
slicing the output would be `["Hello \"World\"\nline 2"]`.
A slightly more efficient implementation is
```d
string escape(string s)
{
import std.array : appender;
import std.format : FormatSpec, formatValue;
FormatSpec!char f;
auto w = appender!string;
w.reserve(s.length);
formatValue(w, [s], f);
return w[][2 .. $ - 2];
}
```
Without allocations. This took me longer than I had hoped it would. It
needs the 1-char buffer to avoid sending the surrounding quotes.
```d
struct EscapedString
{
string[1] str;
this(string str) @nogc pure nothrow @safe { this.str[0] = str; }
void toString(Out)(auto ref Out output)
{
import std.format;
import std.range;
char buf; // 0xff => empty, 0x0, empty, but not first
void putter(const(char)[] data) {
if(!data.length) return;
if(buf != 0xff)
{
if(buf)
put(output, buf);
}
else
// skip first "
data = data[1 .. $];
if(!data.length){
buf = 0;
return;
}
put(output, data[0 .. $-1]);
buf = data[$-1];
}
scope x =
formattedWrite(x, "%(%s%)", str[]);
}
}
```
It would be nice to expose the escaping functionality from format so
this kind of trickery isn't necessary.
-Steve
Re: How to escape control characters?
On Thursday, 31 March 2016 at 03:15:49 UTC, cy wrote:
This might be a dumb question. How do I format a string so that
all the newlines print as \n and all the tabs as \t and such?
The easiest is this:
```d
import std.conv;
string str = `Hello "World"
line 2`;
writeln([str].text[2..$-2]); // Hello \"World\"\nline 2
```
I know this is an old post, but I felt this trick needed to be
shared.
This takes advantage of the fact that `std.format` escapes the
characters in an array of strings. So we create an array where
`str` is the only element, and convert that to text. Without the
`[2..$-2]` slicing the output would be `["Hello \"World\"\nline
2"]`.
A slightly more efficient implementation is
```d
string escape(string s)
{
import std.array : appender;
import std.format : FormatSpec, formatValue;
FormatSpec!char f;
auto w = appender!string;
w.reserve(s.length);
formatValue(w, [s], f);
return w[][2 .. $ - 2];
}
```
And the inverse:
```d
string unescape(string s)
{
import std.format : FormatSpec, unformatValue;
FormatSpec!char f;
string str = `["` ~ s ~ `"]`;
return unformatValue!(string[])(str, f)[0];
}
```
Perhaps `escape()` and `unescape()` should be part of
`std.format` so that they can be refactored to use
`std.format.internal.write.formatElement` directly, eliminating
the conversion to array.
-- Bastiaan.
