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Break apart long commandline testing method

Answer 1

+5 A:

I'm sure that there's an equivalent of getopt(3) function for Windows. Here's the first hit from Google - Pete Wilson. Or you can look into Boost Program Options for a decent C++ library.

Nikolai N Fetissov 2009-05-20 00:51:32

Would the boost library (I'm already using boost) support reading the following as a single argument? [ -files"C:\Documents and Settings\User\Desktop\InFile.txt" ] Note how the token is not quoted, and does contain spaces. The quotes start inside the token itself.

Billy ONeal 2009-05-20 02:35:04

Try it, it's really simple to use.

Nikolai N Fetissov 2009-05-20 03:19:31

Tried it .. doesn't work in my current scenario. Project implements a recursive-descent parser on the commandline. For example:`progname C:\Windows\* AND -tf OR *.dll OR *.exe` prints all files in windows that are files (not folders), or are .dll, or are .exe.The boost library is designed around options coming in pairs -- it's not complex enough for my application. I'm sorry.

Billy ONeal 2009-05-21 03:19:35

OK, I'd didn't get your requirements from the original question - you were talking about options, not a language. On the other hand, recursive-descent parsing is not all that hard, but it really pays off to define (or at least write down) your grammar. I prefer to write proper (even if simple) lexer and parser and build the AST for anything like that.

Nikolai N Fetissov 2009-05-21 03:48:58

Answer 2

+2 A:

What you're needing is a command line option parser library to take care of the messy details of processing the commandline arguments.

I'm not sure which one is the best for C++ since I'm a C# developer who uses CSharpOptParse...but the concept should be the same so hopefully knowing what to look for will point you in the right direction.

mezoid 2009-05-20 01:03:05

Not sure I can do that because my application supports some pretty bizarre commandlines. For example, this is perfectly valid:-files"C:\Documents and Settings\User\Desktop\InFile.txt"Note how the quotes are handled in a non-standard manner and are treated as one token.My question I guess is more of a structural one.

Billy ONeal 2009-05-20 02:33:48

Answer 3

A:

HI All, i wrote this little helper for working with commandlines. I also updated it to work with the funky: --file'thing' and split as the questioner needs. To make it use another character type just do a replace of the char type with what you are using. This is a fully working example you can paste into a main.cpp and run. The code does proper escaping, quotegrouping and : and = '" as name/value splitters for args so you can do --flag:1 or -file"c:\test". Do note space is used as the option splitter. It would look something like this to use it in code:

optparse opt(argstring); g_someint = strtoul(opt.get('--debuglevel','0'),0,0); g_somebool = opt.get('--flag')!=0; g_somestring = opt.get('--file','default.txt')

To answer the question: you can see that this makes your argument processing code so simple, you really dont need to modularize it. Its readable and maintainable.

#include <string.h>
#include <stdio.h>  

struct optparse{
    optparse(const char *args, size_t len = 0) : first(0) {
        size_t i;
        if(!args)args = "";
        if(!len)for(;args[len];len++);
        for(buf=new char[len+1],i=0;i<len;i++)buf[i]=args[i];buf[i]=0;
        opt *last = first;
        char *c = buf, *b = c, *v = 0, g = 0, e = 0;
        do{
            if(*c=='\\') e = e?0:1;
            else if(e?--e:1){
                if(g){ if(*c == g) g = 0; }
                else {    
                    if(*c=='"' || *c=='\''){ if(b<c && !v) v = c; g = *c; }
                    else if(!v && (*c==':' || *c=='='))    v = c; 
                    else if(*c==' '){                    
                        if(b<c)last = new opt(last,&first,b,c,v); 
                        b = c+1, v = 0;
                    }
                }
            }
            if(*c) c++;
            if(!*c && b<c) last = new opt(last,&first,b,c,v);
        }while(*c);
        for(opt *i = first; i; i = i->next) *(i->ne) = 0, *(i->ve) = 0;
    }  
    ~optparse(){
        delete buf;
        while(first){
            opt *t = first->next;
            delete first;
            first = t ;
        }
    }  

    const char *get( const char *name, const char *def= 0){
        size_t l = strlen(name);
        for(opt *i = first;i;i = i->next) if( _strnicmp( i->name, name, l ) == 0) 
            return i->value;
        return def;
    }  

    struct opt{
        opt( opt *last, opt **first, char *s, char *e, char *v){
            if(!*first) *first = this; if(last) last->next = this;
            if(v && (*v=='\'' || *v=='"') && (*(e-1)=='\'' || *(e-1) == '"'))e--;
            next = 0, name = s, value = v?v+1:"", ne = v?v:e, ve = e; 
        }
        char *name, *value, *ne, *ve;
        opt *next;
    };  
    char *buf;
    opt *first;
};  

int main(){  

    const char *v, *test ="--debug:1 -file'c:\\something' --odd=10";
    optparse opts(test);  

    if(v = opts.get("--debug")){
       printf("debug flag value is %s\n",v);
    }  

    for(optparse::opt *i=opts.first;i;i=i->next){
        printf("name: %s value: %s\n",i->name,i->value);
    }  
}

The parser is very easily tweaked to support different types of argument processing. For instance if you replace

if(b<c)last = new opt(last,&first,b,c,v); 
b = c+1, v = 0;

with

if(*b=='-' && *(c+1)!='-')v = v?v:c;
else{
   if(b<c)last = new opt(last,&first,b,c,v); 
   b = c+1, v = 0;
}

You will have added the feature of joining space-split arguments as 'value' like: -debug 1 or --files a.txt b.txt c.txt Also if you dislike the : as a split param (might be bothersome in windows apps) just remove the ==':'

2009-06-22 05:51:12

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Break apart long commandline testing method

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