Colorize and stylize strings at compile-time, by using an HTML-like syntax.
This library provides three macros:
- `cformat!(<FORMAT_STRING> [, ARGS...])`
- `cprint!(<FORMAT_STRING> [, ARGS...])`
- `cprintln!(<FORMAT_STRING> [, ARGS...])`
Each of them have the same syntax as `format!()`, `print!()` and `println!()` respectively, but
they accept an additional syntax inside the format string: HTML-like tags which add terminal
colors/styles at compile-time.
*Note*: these tags are commonly named "*color tags*" in the documentation below.
## What does it do ?
By default, the provided macros will replace the color tags found in the format string by ANSI
hexadecimal escape codes. E.g.:
``` rust
cprintln!("HELLO <green>WORLD</green>")
```
will be replaced by:
``` rust
println!("HELLO \x1b[31mWORLD\x1b[39m")
```
*Note*: it is possible to change this behaviour by activating the feature `terminfo`. Then it will
question the `terminfo` database at runtime in order to know which sequence to write for each kind
of styling/colorizing (see below for more detail).
# Pros/cons of this crate
## Pros
* Styling is processed at compile-time, so the runtime payload is quite inexistant (unless the
feature `terminfo` is activated);
* Nested tags are well handled, e.g. `"<green>...<blue>...</blue>...</green>"`;
* Some optimizations are performed to avoid redundant ANSI sequences, because these
optimizations can be done at compile-time without impacting the runtime;
* Almost every tag has a short name, so colorizing can be done quickly: `"my <b>blue</> word"`;
* Each provided macro can be used exactly in the same way as the standard `format!`-like
macros; e.g., positional arguments and named arguments can be used as usual;
* Fine-grained error handling.
## Cons
* Not compatible with non-ANSI Windows terminals (and not tested at all on Windows, feedbacks
are welcome);
* Not tested on Mac, feedbacks are welcome.
# Introduction
## Basic example
``` rust
use color_print::cprintln;
fn main() {
cprintln!("Hello <green>world</green>!");
}
```
## Closing a tag more simply: the `</>` tag
Basically, tags must be closed by giving exactly the same colors/styles of the matching open
tag (with a slash `/` at the beginning). But it can be tedious!
So, it is also possible to close the last open tag simply with `</>`:
``` rust
cprintln!("Hello <green>world</>!");
```
## Combining colors and styles
Multiple styles and color(s) can be combined into a single tag by separating them with the `;`
semicolon character:
``` rust
cprintln!("This a <green;bold>green and bold text</green;bold>.");
// The same, but closing with the </> tag:
cprintln!("This a <green;bold>green and bold text</>.");
```
Of course, combining multiple foreground colors or multiple background colors into the same tag
is useless (in such a case, only the last one is taken into account).
## Nesting tags
Any tag can be nested with any other, as long as the closing tags match correctly (following
the basic rules of nesting for HTML tags):
``` rust
cprintln!("<green>This is green, <bold>then green and bold</bold>, then green again</green>");
cprintln!("<green>This is green, <bold>then green and bold</>, then green again</>");
// Colors can be nested as well:
cprintln!("<green>This is green, <blue>then blue</blue>, then green again</green>");
cprintln!("<green>This is green, <blue>then blue</>, then green again</>");
```
## Unclosed tags are automatically closed at the end of the format string
Tags which have not been closed manually will be closed automatically, which means that the
ANSI sequences needed to go back to the original state will be added:
``` rust
// The two following lines are strictly equivalent:
cprintln!("<green><bold>Hello");
cprintln!("<green><bold>Hello</></>");
```
## How to display the chars `<` and `>` verbatim
As for `{` and `}`, the chars `<` and `>` have to be doubled in order to display them verbatim:
``` rust
cprintln!("This is an angle bracket character: <<, and here is another one: >>");
```
# Optimization: no redundant ANSI codes
The expanded format string will only contain the *needed* ANSI codes. This is done by making a
diff of the different style attributes, each time a color tag is encountered, instead of
mechanically adding the ANSI codes.
E.g., several nested `<bold>` tags will only produce one bold ANSI sequence:
``` rust
cprintln!("<bold><bold>A <bold;blue>B C D</> E</></>")
```
will be replaced by:
``` rust
println!("\x1b[1mA \x1b[34mB C D\x1b[39m E\x1b[22m")
// ^-----^ ^------^ ^------^ ^------^
// bold blue color no bold
// reset
```
# The feature `terminfo`
Instead of inserting ANSI sequences directly into the format string, it is possible to activate
the feature `terminfo`: this will add the format sequences at runtime, by consulting the
`terminfo` database.
This has one pro and several cons:
#### Pros
* This adds a level of compatibility for some terminals.
#### Cons
* This adds a little runtime payload;
* This adds two dependencies: [`lazy_static`] and [`terminfo`];
* The styles `<strike>` and `<conceal>` are not handled;
* With `terminfo`, many styles are not resettable individually, which implies longer format
sequences for the same result;
* For now, the provided macros can only be used in one thread.
[`lazy_static`]: https://crates.io/crates/lazy_static
[`terminfo`]: https://crates.io/crates/terminfo
# Naming rules of the color tags:
Each color/style tag has at least a long name, like `<magenta>` or `<underline>`.
The tags directly relative to *colors* (like `<red>`, `<bg-blue>`, `<bg-bright-green>`..., as
opposed to *style* tags like `<bold>`, `<italics>`...) have some common naming rules:
* Each color tag has four variants:
- `<mycolor>`: the normal, foreground color;
- `<bright-mycolor>`: the bright, foreground color;
- `<bg-mycolor>`: the normal, background color;
- `<bg-bright-mycolor>`: the bright, background color;
* Each color tag has a *shortcut*, with a base letter for each color (example with the `x`
letter):
- `<x>`: the normal, foreground color;
- `<x!>`: the bright, foreground color;
- `<X>`: the normal, background color;
- `<X!>`: the bright, background color;
* Except for the color `<black>`, each color's shortcut letter is simply the first letter of
its name, e.g. `<y>` is the shortcut for `<yellow>`;
* Each color's shortcut tag which is uppercase is a background color;
* Each tag which has a trailing exclamation point `!` is a bright color;
* Finally, each bright color has also a "medium name" with an exclamation point `!`.
# List of accepted color/style tags:
The two first columns show which styles are supported, respectively with the default crate features
(ANSI column), and with the feature `terminfo` being activated.
| X | X | `<bold>` | `<em>`, `<strong>` | `<s>` |
| X | X | `<dim>` | | |
| X | X | `<underline>` | | `<u>` |
| X | | `<strike>` | | |
| X | X | `<reverse>` | `<rev>` | |
| X | | `<conceal>` | `<hide>` | |
| X | X | `<italics>` | `<italic>` | `<i>` |
| X | X | `<blink>` | | |
| X | X | `<black>` | | `<k>` |
| X | X | `<red>` | | `<r>` |
| X | X | `<green>` | | `<g>` |
| X | X | `<yellow>` | | `<y>` |
| X | X | `<blue>` | | `<b>` |
| X | X | `<magenta>` | | `<m>` |
| X | X | `<cyan>` | | `<c>` |
| X | X | `<white>` | | `<w>` |
| X | X | `<bright-black>` | `<black!>` | `<k!>` |
| X | X | `<bright-red>` | `<red!>` | `<r!>` |
| X | X | `<bright-green>` | `<green!>` | `<g!>` |
| X | X | `<bright-yellow>` | `<yellow!>` | `<y!>` |
| X | X | `<bright-blue>` | `<blue!>` | `<b!>` |
| X | X | `<bright-magenta>` | `<magenta!>` | `<m!>` |
| X | X | `<bright-cyan>` | `<cyan!>` | `<c!>` |
| X | X | `<bright-white>` | `<white!>` | `<w!>` |
| X | X | `<bg-black>` | | `<K>` |
| X | X | `<bg-red>` | | `<R>` |
| X | X | `<bg-green>` | | `<G>` |
| X | X | `<bg-yellow>` | | `<Y>` |
| X | X | `<bg-blue>` | | `<B>` |
| X | X | `<bg-magenta>` | | `<M>` |
| X | X | `<bg-cyan>` | | `<C>` |
| X | X | `<bg-white>` | | `<W>` |
| X | X | `<bg-bright-black>` | `<bg-black!>` | `<K!>` |
| X | X | `<bg-bright-red>` | `<bg-red!>` | `<R!>` |
| X | X | `<bg-bright-green>` | `<bg-green!>` | `<G!>` |
| X | X | `<bg-bright-yellow>` | `<bg-yellow!>` | `<Y!>` |
| X | X | `<bg-bright-blue>` | `<bg-blue!>` | `<B!>` |
| X | X | `<bg-bright-magenta>` | `<bg-magenta!>` | `<M!>` |
| X | X | `<bg-bright-cyan>` | `<bg-cyan!>` | `<C!>` |
| X | X | `<bg-bright-white>` | `<bg-white!>` | `<W!>` |