Print3

A cat-like programming built for C3 source files, it will try to highlight the source like inside an editor.

Example:

A special thank you to @ManuLinares for the regex that selects any valid C3 number (including the fun stuff like 1.3e-39 or 32ull)!

Usage:

./print3 [options...] file(s)

Print C3 files with colours. A bit akin to 'cat' or 'bat'.

Options and files can generally be mixed, only when an option requires
an argument, it is expected to follow directly behind.

Available options:
 -h, --help              Show this help message

 --tabsize <number>      Amount of spaces to replace tab characters (default 4)
 --nonumber              Show no line numbers
 --nrformat <text>       Format for numbers (f.e. "%d | ").
 --line-start <number>   Start printing from this line (inclusive, default 0)
 --line-stop <number>    Stop printing at this line (inclusive, default -1)

 --pager                 Send output to 'less -R'

 --print-buffer-size <number>
                         Set the size of the print buffer (bytes, default 128)
 --read-buffer-size <number>
                         Set the size of the read buffer (bytes, default 512)

 --colour-<thing> <text> Set the colour for <thing> to <text>, should be
                         specified in "#RRGGBB" format. Available things:
                         at, call, comment, comptime_ident, constant, ident,
                         keyword, member, number, string, symbol, type.

 Allowed format for --nrformat:
   %[-][0._][1-9]d

       - Starts with '%' and ends with 'd'
       - Optionally '-' to set alignment to left (default right)
       - Optionally '0', '.' or '_' to use as padding character
       - Optionally 1-9 as minimum width specifier (default 3)
       - Fixed text is allowed before and after the number

       Examples: "%d", "line - %-5d :"

Fun IO optimization

I spent some time looking at optimizing print3 , and perf showed me that C3's printf machine took quite some time. I decided to try and replace all printf occurences with multiple print calls and see if that speeded up things:

io::printf(
    "%s%s%s",
    Ansi.BRIGHT_GREEN,
    word,
    Ansi.RESET
);
// became
io::print(Ansi.BRIGHT_GREEN);
io::print(word);
io::print(Ansi.RESET);

This sped up things by almost 2.5x.

Some slight tweaking to this by caching stdout and creating my own BufferedOutput abstraction, hyperfine showed some fun results:

Benchmark 1: ./build/old_print3 long.c3
  Time (mean ± σ):     178.5 ms ±   1.7 ms    [User: 167.0 ms, System: 10.7 ms]
  Range (min … max):   175.9 ms … 184.3 ms    100 runs

Benchmark 2: ./build/print3 long.c3
  Time (mean ± σ):      47.1 ms ±   0.6 ms    [User: 35.8 ms, System: 11.1 ms]
  Range (min … max):    45.7 ms …  48.5 ms    100 runs

Summary
  ./build/print3 long.c3 ran
    3.79 ± 0.06 times faster than ./build/old_print3 long.c3

In short: when the main goal of your application is printing a file to the terminal, spend some time optimising that printing part. The standard library is made for ergonomics, not for raw speed in specialised usecases.

Small sidenote, with some other optimisations, benchmarks now show that print3 can print my long.c3 test-file in just 13ms. Maybe I write an article some day about the steps taken to get there.