www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - new to D2.0 , invariant problem

reply MikeRJ <MeanMike live.com> writes:
For some reason i think DM 1.0 is slowly dieing as i see tons of new features
in D 2.0's phobos not implemented in D 1.0  so im trying to migrate to D2.0

my 1st problem is when i compile code:

	bool open(char[] fn, char[] mode="rb")
	{
		filename=fn.dup;
		file = fopen(toStringz(filename), toStringz(mode));
		if (!file) return false;
		return true;
	}

i receive error:

 cannot implicitly convert expression ("rb") of type invariant(char[2u]) to
char[]|


Nov 19 2008
next sibling parent Jesse Phillips <jessekphillips gmail.com> writes:
On Wed, 19 Nov 2008 22:10:50 -0500, MikeRJ wrote:

 For some reason i think DM 1.0 is slowly dieing as i see tons of new
 features in D 2.0's phobos not implemented in D 1.0  so im trying to
 migrate to D2.0
 
 my 1st problem is when i compile code:
 
 	bool open(char[] fn, char[] mode="rb") {
 		filename=fn.dup;
 		file = fopen(toStringz(filename), toStringz(mode)); if (!

 		false;
 		return true;
 	}
 
 i receive error:
 
 cannot implicitly convert expression ("rb") of type
 invariant(char[2u]) to char[]|



bool open(char[] fn, char[] mode="rb".dup) { will probably make it compile, but since you are using D2 I think the correct methodology would be: bool open(string fn, string mode="rb") { Since you don't make changes to fn or mode they should be invariant. Also, D1 is not dieing, it is not supposed to get any new features. D2 is continually changing which would not be good if you are doing application development.
Nov 19 2008
prev sibling next sibling parent Kagamin <spam here.lot> writes:
MikeRJ Wrote:

 	bool open(char[] fn, char[] mode="rb")
 	{
 		filename=fn.dup;
 		file = fopen(toStringz(filename), toStringz(mode));
 		if (!file) return false;
 		return true;
 	}

D1 and D2 compatible code: bool open(in char[] fn, in char[] mode="rb") { file = fopen(toStringz(fn), toStringz(mode)); if (!file) return false; return true; }
Nov 20 2008
prev sibling parent "Steven Schveighoffer" <schveiguy yahoo.com> writes:
"MikeRJ" wrote
 For some reason i think DM 1.0 is slowly dieing as i see tons of new 
 features in D 2.0's phobos not implemented in D 1.0  so im trying to 
 migrate to D2.0

 my 1st problem is when i compile code:

 bool open(char[] fn, char[] mode="rb")
 {
 filename=fn.dup;
 file = fopen(toStringz(filename), toStringz(mode));
 if (!file) return false;
 return true;
 }

 i receive error:

 cannot implicitly convert expression ("rb") of type invariant(char[2u]) 
 to char[]|



The correct const-contract usage is: bool open(const(char)[] fn, const(char)[] mode = "rb") That is, you are saying open does not modify fn or mode. It simply uses them as input parameters. The D1/D2 compatible version that Kagamin posted is also legal (and pretty much the same thing). -Steve
Nov 20 2008