GitHub - yoav-lavi/melody: Melody is a language that compiles to regular express...

Melody is a language designed to compile to and maintain a 1-1 relationship with regular expressions, while being more readable and maintainable.

The current goal is supporting the JavaScript implementation of regular expressions.

Melody is very new and is unstable at the moment

Examples

Note: these are for the currently supported syntax and may change

Batman Theme

16 of "na";

2 of match {
  <space>;
  "batman";
}

// 🦇🦸‍♂️

Turns into

/(?:na){16}(?:\sbatman){2}/

Twitter Hashtag

"#";
some of <word>;

// #melody

Turns into

/#\w+/

Introductory Courses

some of <word>;
<space>;
"1";
2 of <digit>;

// classname 1xx

Turns into

/\w+\s1\d{2}/

Indented Code (2 spaces)

some of match {
  2 of <space>;
}

some of char;
";";

//  let value = 5;

Turns into

/(?:\s{2})+.+;/

Install

From Source

git clone https://github.com/yoav-lavi/melody.git
cd melody
cargo install --path .

CLI Usage

melody [OPTIONS] <PATH>

OPTIONS:
  -f, --file <FILE>    write to an output file
  -n, --no-color       print output with no color
  -V, --version        print version information
  -h, --help           print help information

Keywords

• of - used after a number or a range and before a sequence to be matched, e.g. 5 of "A";, equivalent to regex {5}
• to - used to create a range (either as a quantifier or as a character range), e.g. 5 to 9, equivalent to regex {5,9} if before an of or [5-9] otherwise
• capture - used to open a capture or named capture block, equivalent to regex (...)
• match - used to open a match block, equivalent to regex (?:...)
• start - matches the start of the string, equivalent to regex ^
• end - matches the end of the string, equivalent to regex $
• char - matches a single character, equivalent to regex .
• some - used with of to express 1 or more of a pattern, equivalent to regex +
• over - used with of to express more than an amount of a pattern, equivalent to regex {6,} (assuming over 5 of ...)

Symbols

• <space> - equivalent to regex \s
• <newline> - equivalent to regex \n
• <tab> - equivalent to regex \t
• <return> - equivalent to regex \r
• <feed> - equivalent to regex \f
• <null> - equivalent to regex \0
• <digit> - equivalent to regex \d
• <vertical> - equivalent to regex \v
• <word> - equivalent to regex \w

Concepts

• "..." or '...' - used to mark a literal part of the match

Extras

• // - used to mark comments

File Extension

The Melody file extension is .mdy

Syntax Highlighting

VSCode

Get the extension here

Feature Status

- Implemented

- Partially implemented

- Not implemented

- Unclear whether this will be implemented

- Unclear what the syntax will be

Melody Regex Status

5 of "hello"; (?:hello){5} 5 to 7 of "A"; A{5,7} capture { ... } (...) capture name { ... } (?<name>...) match { ... } (?:...) <space>; \s A to Z; [A-Z] a to z; [a-z] 0 to 9; [0-9] // comment

start; ^ end; $ <newline>; \n <tab>; \t <return>; \r <feed>; \f <null>; \0 <digit>; \d <vertical>; \v <word>; \w "..."; (raw) ... '...'; (raw) ... '\''; ' "\""; "

support non alphanumeric characters

output to file

no color output

char . some of +

syntax highlighting extension

over 5 of "A"; A{6,}

enforce group close

tests

not <space>; \S not <digit>; \D not <word>; \W <backspace> [\b]

file watcher

nested groups (...(...))

multiple ranges [a-zA-Z0-9]

general cleanup and modules

auto escape for non Melody patterns

rust library / macro

TS/JS build step

more robust parsing mechanism (ast)

not "A"; [^A] flags: global, multiline, ... /.../gm... /* comment */

maybe of ? maybe some of * either of ..., ... | any of "a", "b", "c" [abc] ... not before ... ...(?!...) ... not after ... ...(?<!...) ... before ... ...(?=...) ... after ... ...(?<=...)

(?) *?

(?) \#

(?) \k<name>

(?) \p{...}

(?) \P{...}

(?) \uYYYY

(?) \xYY

(?) \ddd

(?) \cY

(?) \b

(?) \B

(?) $1

(?) $`

(?) $&

(?) x20

(?) x{06fa}

variables / macros

regex optimization

standard library / patterns

reverse compiler

Acknowledgments

Melody uses: