1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
[](https://github.com/mhekkel/libmcfp/actions)
[](https://github.com/mhekkel/libmcfp/actions)
# libmcfp
A library for parsing command line arguments and configuration files and making them available throughout a program.
There's a config file parser as well.
> **_NOTE:_** The naming of libmcfp has changed again in version 1.3.4 reverting the rename of 1.3.3. To use libmcfp you should use find_package(mcfp) and link to mcfp::mcfp
## Synopsis
```cpp
// Example of using libmcfp
#include <iostream>
#include <filesystem>
#include <mcfp/mcfp.hpp>
int main(int argc, char * const argv[])
{
// config is a singleton
auto &config = mcfp::config::instance();
// Initialise the config object. This can be done more than once,
// e.g. when you have different sets of options depending on the
// first operand.
config.init(
// The first parameter is the 'usage' line, used when printing out the options
"usage: example [options] file",
// Flag options (not taking a parameter)
mcfp::make_option("help,h", "Print this help text"),
mcfp::make_option("verbose,v", "Verbose level, can be specified more than once to increase level"),
// A couple of options with parameter
mcfp::make_option<std::string>("config", "Config file to use"),
mcfp::make_option<std::string>("text", "The text string to echo"),
// And options with a default parameter
mcfp::make_option<int>("a", 1, "first parameter for multiplication"),
mcfp::make_option<float>("b", 2.0f, "second parameter for multiplication"),
// You can also allow multiple values
mcfp::make_option<std::vector<std::string>>("c", "Option c, can be specified more than once"),
// This option is not shown when printing out the options
mcfp::make_hidden_option("d", "Debug mode")
);
// There are two flavors of calls, ones that take an error_code
// and return the error in that code in case something is wrong.
// The alternative is calling without an error_code, in which
// case an exception is thrown when appropriate
// Parse the command line arguments here
std::error_code ec;
config.parse(argc, argv, ec);
if (ec)
{
std::cerr << "Error parsing argument " << std::quoted(config.get_last_option()) << ": " << ec.message() << std::endl;
exit(1);
}
// First check, to see if we need to stop early on
if (config.has("help") or config.operands().size() != 1)
{
// This will print out the 'usage' message with all the visible options
std::cerr << config << std::endl;
exit(config.has("help") ? 0 : 1);
}
// Configuration files, read it if it exists. If the users
// specifies an alternative config file, it is an error if that
// file cannot be found.
config.parse_config_file("config", "example.conf", { "." }, ec);
if (ec)
{
std::cerr << "Error parsing config file, option " << std::quoted(config.get_last_option()) << ": " << ec.message() << std::endl;
exit(1);
}
// If options are specified more than once, you can get the count
int VERBOSE = config.count("verbose");
// Operands are arguments that are not options, e.g. files to act upon
std::cout << "The first operand is " << config.operands().front() << std::endl;
// Getting the value of a string option
auto text = config.get<std::string>("text", ec);
if (ec)
{
std::cerr << "Error getting option text: " << ec.message() << std::endl;
exit(1);
}
std::cout << "Text option is " << text << std::endl;
// Likewise for numeric options
int a = config.get<int>("a");
float b = config.get<float>("b");
std::cout << "a (" << a << ") * b (" << b << ") = " << a * b << std::endl;
// And multiple strings
for (std::string s : config.get<std::vector<std::string>>("c"))
std::cout << "c: " << s << std::endl;
return 0;
}
```
## Installation
Use [cmake](https://cmake.org/) to install _libmcfp_.
```bash
git clone https://github.com/mhekkel/libmcfp.git
cd libmcfp
cmake -S . -B build
cmake --build build
cmake --install build
```
|
