xo-alloc/README.md

nestlog -- logging with automatic call-graph indenting

Nestlog is a lightweight header-only library for console logging.

Features

• header-only; nothing to link
• easy-to-read format uses indenting to show call structure. indentation has user-controlled upper limit to preserve readability with deeply nested call graphs
• colorized output using vt100 color codes (ansi or xterm)
• automatically captures + displays timestamp, function name and code location. supports several function-name formats to reflect tradeoff readability for precision
• application code may issue logging code that contains embedded newlines and/or color escapes; logger preserves indentation.
• logger is 'truthy' -> only pay for formatting when entry points is enabled.
• also provides family of convenience stream-inserters

Examples

1

/* examples/ex1/ex1.cpp */

#include "nestlog/scope.hpp"

void A(int x) {
    XO_SCOPE(log);  // i.e. xo::scope log("A");

    log("enter ", ":x ", x);
}

int
main(int argc, char ** argv) {
    A(66);
}

output:

+A
 enter :x 66
-A

2

/* examples ex2/ex2.cpp */

#include "nestlog/scope.hpp"

using namespace xo;

int
fib(int n) {
    scope log(XO_ENTER0(info), ":n ", n);

    int retval = 1;

    if (n >= 2) {
        retval = fib(n - 1) + fib(n - 2);
        log && log(":n ", n);
    }

    log.end_scope("<- :retval ", retval);

    return retval;
}

int
main(int argc, char ** argv) {
    log_config::min_log_level = xo::log_level::info;
    log_config::indent_width = 4;

    int n = 4;

    scope log(XO_ENTER0(info), ":n ", 4);

    int fn = fib(n);

    log && log(":n ", n);
    log && log("<- :fib(n) ", fn);
}

output:

3 example exposing runtime configuration options

```
/* examples ex3/ex3.cpp */

#include "nestlog/scope.hpp"

using namespace xo;

int
fib(int n) {
    scope log(XO_ENTER0(info), tag("n", n));

    int retval = 1;

    if (n >= 2) {
        retval = fib(n - 1) + fib(n - 2);
    }

    log.end_scope(tag("n", n), " <-", xtag("retval", retval));

    return retval;
}

int
main(int argc, char ** argv) {
    log_config::min_log_level = log_level::info;
    log_config::time_enabled = true;
    log_config::time_local_flag = true;
    log_config::style = FS_Streamlined;
    log_config::indent_width = 4;
    log_config::max_indent_width = 30;
    log_config::location_tab = 80;
    log_config::encoding = CE_Xterm;
    log_config::function_entry_color = 69;
    log_config::function_exit_color = 70;
    log_config::code_location_color = 166;

    int n = 3;

    scope log(XO_ENTER0(info), ":n ", 4);

    int fn = fib(n);

    log && log(tag("n", n));
    log && log("<-", xtag("fib(n)", fn));
}

/* ex3/ex3.cpp */
```

output: