# Live Action Search and Replace (LASR)
When performing a global search-and-replace using e.g. `sed`, it can be difficult to hone in on the exact correct pattern.
`lasr` makes this easier by showing live results as you type.
# Installation
Binary artifacts can be downloaded from the [releases page](https://github.com/rcorre/lasr/releases).
If you have a rust toolchain, you can install from source:
```bash
cargo install lasr
```
# Usage
Simply run `lasr` to start a search-and-replace in the current directory. You may run `lasr <path> [<path>...]` to search a specific directories or files.
This will open a TUI where you can start typing a search pattern and see live matches below.
Once you are happy with the search pattern, press <kbd>Tab</kbd> to start editing the replacement pattern.
Finally, press <kbd>Enter</kbd> to confirm and execute the replacement, or <kbd>Esc</kbd> to cancel the replacement.
You can press <kbd>Ctrl+S</kbd> to toggle case-insensitive searching, or pass the `-i` flag to enable case-insensitive search on startup.
# Syntax
The pattern syntax is based on the rust [regex](https://docs.rs/regex/latest/regex/#syntax) crate.
The replacement syntax is based on the [replace](https://docs.rs/regex/latest/regex/struct.Regex.html#method.replace) method in that crate.
Replacements may reference numbered groups as `$1` or `${1}`, or named groups like `$foo` or `${foo}`. The `{}` brackets may be necessary to separate the replacement from other text. `$0` or `${0}` refers to the entire match.
# Configuration
The configuration file is located at `$XDG_CONFIG_HOME/lasr/lasr.toml` (`~/.config/lasr/lasr.toml` by default).
The current configuration can be printed by running `lasr --dump-config`. This can be used as a starting point to edit your own configuration:
```bash
lasr --dump-config > ~/.config/lasr/lasr.toml
```
## Default Config
```toml
[theme.base]
fg = "Reset"
[theme.find]
fg = "Red"
add_modifier = "CROSSED_OUT"
[theme.replace]
fg = "Green"
add_modifier = "BOLD"
[keys]
c-b = "cursor_left"
c-s = "toggle_ignore_case"
tab = "toggle_search_replace"
left = "cursor_left"
home = "cursor_home"
c-e = "cursor_end"
c-d = "delete_char"
right = "cursor_right"
c-h = "delete_char_backward"
enter = "confirm"
backspace = "delete_char_backward"
c-k = "delete_to_end_of_line"
c-a = "cursor_home"
end = "cursor_end"
c-f = "cursor_right"
c-c = "exit"
esc = "exit"
c-u = "delete_line"
c-w = "delete_word"
```
## General Config
The following settings may be placed at the top-level of the config, not under any section:
| `threads` | Threads to use, 0 to auto-select | `0` |
| `auto_pairs` | Auto-insert mathching pairs of `({[` | `true` |
## Theme Config
The `theme` section of the config includes 3 "style" sub-sections:
| `base` | Most text/UI |
| `find` | Text matched by the pattern |
| `replace` | Replacement text |
A "style" has the following attributes
| `fg` | Foreground color |
| `bg` | Background color |
| `add_modifier` | Add modifiers |
| `sub_modifier` | Remove modifiers |
A color can be an [ANSI color name] like `"red"`, an [ANSI 8-bit color index] like `"7"`, or a hex string like `"#00FF00"`.
[ANSI color name]: https://docs.rs/ratatui/latest/ratatui/style/enum.Color.html
[ANSI 8-bit color index]: https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
`add_modifier` and `sub_modifier` can be one of the following:
- `"BOLD"`
- `"DIM"`
- `"ITALIC"`
- `"UNDERLINED"`
- `"SLOW_BLINK"`
- `"RAPID_BLINK"`
- `"REVERSED"`
- `"HIDDEN"`
- `"CROSSED_OUT"`
## Keys Config
The `keys` section specifies key bindings. Each key is a single character or key name, optionally followed by "c-" and/or "a-" to specify a ctrl or alt modifier. The following are valid key names:
- <kbd>a</kbd>-<kbd>z</kbd>, <kbd>0</kbd>-<kbd>9</kbd>
- <kbd>f0</kbd>-<kbd>f12</kbd>
- <kbd>backspace</kbd>
- <kbd>enter</kbd>
- <kbd>left</kbd>
- <kbd>right</kbd>
- <kbd>up</kbd>
- <kbd>down</kbd>
- <kbd>home</kbd>
- <kbd>end</kbd>
- <kbd>pageup</kbd>
- <kbd>pagedown</kbd>
- <kbd>tab</kbd>
- <kbd>backtab</kbd>
- <kbd>delete</kbd>
- <kbd>insert</kbd>
- <kbd>esc</kbd>
Each value in the `keys` section is one of the following actions:
| `noop` | Do nothing, used to unbind a default key | |
| `exit` | Exit without performing any replacement | <kbd>Esc</kbd>, <kbd>Ctrl+C</kbd> |
| `confirm` | Exit and perform replacements | <kbd>Enter</kbd> |
| `toggle_search_replace` | Switch focus between the "search" and "replace" inputs | <kbd>Tab</kbd> |
| `toggle_ignore_case ` | Toggle ignore case flag | <kbd>Ctrl+S</kbd> |
| `cursor_left` | Move cursor left one character | <kbd>←</kbd>, <kbd>Ctrl+B</kbd> |
| `cursor_right` | Move cursor right one character | <kbd>→</kbd>, <kbd>Ctrl+F</kbd> |
| `cursor_home` | Move cursor to beginning of line | <kbd>Home</kbd>, <kbd>Ctrl+A</kbd> |
| `cursor_end` | Move cursor to end of line | <kbd>End</kbd>, <kbd>Ctrl+E</kbd> |
| `delete_char` | Delete character at cursor position | <kbd>Ctrl+D</kbd> |
| `delete_char_backward` | Delete character before cursor (backspace) | <kbd>Backspace</kbd>, <kbd>Ctrl+H</kbd> |
| `delete_word` | Delete word before cursor | <kbd>Ctrl+W</kbd> |
| `delete_to_end_of_line` | Delete from cursor to end of line | <kbd>Ctrl+K</kbd> |
| `delete_line` | Delete entire line | <kbd>Ctrl+U</kbd> |
# Troubleshooting
Logs are located at `$XDG_CACHE_HOME/lasr/log.txt`. Log verbosity can be increased by setting the environment variable `RUST_LOG` to `debug` or `trace`. See [env_logger](https://docs.rs/env_logger/latest/env_logger/) for more info.
# Other cool search/replace tools
- [sad](https://github.com/ms-jpq/sad) allows you to approve/reject each replacement, but must be re-run each time you change the pattern.
- [sd](https://github.com/chmln/sd) provides a simpler CLI alternative to `sed`, but is not interactive.
- [ast-grep](https://github.com/ast-grep/ast-grep) is like `sed`/`grep`, but using tree-sitter to match code syntax.
