This is a simple language which compiles into a "Regular Expression". The language is inspired by the post of u/johnngnky on Reddit.
I don't follow the post from him but the way I created the syntax is inspired by his post and I got the idea to make this from him.
The project is in an very early state and is not mend to be used in an actual application.
SRL has a few data types you should know before starting to work with SRL.
| Name | Usage | Description |
|---|---|---|
| Number | $5 | A number is idecated by a $ |
| String | "Foo" | A string is contained inside two " |
| Constant | !digit | A constant is indecated by a ! |
Constants are pre defined patterns that can be reused.
| Name | Usage | RegExp | Description |
|---|---|---|---|
| Any char | !any | . | Any single character |
| Any whitespace | !whitespace | \s | Any whitespace character |
| Any non-whitespace | !!whitespace | \S | Any non-whitespace character |
| Any digit | !digit | \d | Any digit |
| Any non-digit | !!digit | \D | Any non-digit |
| Any word character | !word | \w | Any word character |
| Any non-word character | !!word | \W | Any non-word character |
| Any unicode sequence | !unicode | \X | Any Unicode sequence, linebreaks included |
| Match data unit | !dataunit | \C | Match one data unit |
| Unicode newline | !uninl | \R | Unicode newlines |
| Anything but newline | !!newline | \N | Match anything but a newline |
| Vertical whitespace | !vwhitespace | \v | Vertical whitespace character |
| Negative vertical whitespace | !!vwhitespace | \V | Negation of \v |
| Horizontal whitespace | !hwhitespace | \h | Horizontal whitespace character |
| Negative horizontal whitespace | !!hwhitespace | \H | Negation of \h |
| Reset Match | !reset | \K | Reset match |
| Control character Y | !ycontrol | \cY | Control Character Y |
| Backspace | !backspace | [\b] | Backspace character |
| Newline | !newline | \n | Newline |
| Carriage return | !carriage | \r | Carriage return |
| Tab | !tab | \t | Tab |
| Null character | !null | \0 | Null charachter |
Anchors allows you to jump to certain points.
| Name | Usage | RegExp | Descriptions |
|---|---|---|---|
| Start match | STAT MATCH | \G | Start of match |
| Start input* | START INPUT | ^ / \A | Start of input |
| End input* | END INPUT | $ / \Z | End of input |
| Absolute end input | ABSOLUTE END INPUT | \z | Absolute end of input |
| word boundary | WORD BOUNDARY | \b | A word boundary |
| boundary | BOUNDARY | \B | Non-word boundary |
* ^ and $ match the start and end of a line if Multiline is enabled
Groups are much like normal groups in regex and can be used as such.
There are some different ways how we can use groups.
| Name | Usage | RegExp | Description |
|---|---|---|---|
| Capture enclosed | [...] | (...) | Capture everything enclosed |
| Atomic capture | ATMOIC [...] | (?>...) | Atmoic group (non-capturing) |
| Named group | NAME "Foo" FOR [...] | (?<Foo>) | Named capturing group |
| Define group * | DEFINE "Foo" FOR [...] | Defines a group for later use | |
| Positive lookahead | POSITIVE LOOKAHEAD [...] | (?=...) | Positive lookahead |
| Negative lookahead | NEGATIVE LOOKAHEAD [...] | (?!...) | Negative lookahead |
| Positive lookbehind | POSITIVE LOOKBEHIND [...] | (?<=...) | Positive lookbehind |
| Negative lookbehind | NEGATIVE LOOKBEHIND [...] | (?<!...) | Negative lookbehind |
| If branching | IF ([LITERAL ("foo")]) THEN [LITERAL ("Bar")] ELSE [LITERAL ("barFoo")] | (((?=foo)fooBar)|(barFoo)) | Allows to go through different regex branches |
* Is not supported by the Emacs RegExp Engine, but its implemented via SRL
Quantifiers are used to define how often the last element should be repeated.
| Name | Usage | RegExp | Description |
|---|---|---|---|
| Optional | LITERAL ("a") OPTIONAL | a? | 0 or 1 of a |
| Zero or More* | LITERAL ("a") MANY | a* | 0 or more of a |
| One or More | LITERAL ("a") MANY1 | a+ | 1 or more of a |
| Exact | LITERAL ("a") EXACT ($3) | a{3} | Exactly 3 of a |
| More than | LITERAL ("a") MORE ($3) | a{3,} | 3 or more of a |
| Less than *** | LITERAL ("a") LESS ($3) | a{0,3} | 3 or less of a |
| Between | LITERAL ("a") BETWEEN ($3 $6) | a{3,6} | Between 3 and 6 of a |
| Greedy** | LITERAL ("a") GREEDY | a* | Greedy quantifier |
| Lazy | LITERAL ("a") LAZY | a*? | Lazy quantifier |
| Possessive | LITERAL ("a") POSSESSIVE | a*+ | Possessive quantifier |
* Is replaceable with GREEDY
** Is replaceable with MANY
*** Is not supported by the Emacs RegExp Engine, but its implemented via SRL
Instructions are used to define your patterns.
| Name | Usage | RegExp | Description |
|---|---|---|---|
| From | FROM ("123") | [123] | Single char of |
| Except | EXCEPT ("123") | [^123] | Any other char than |
| Literal | LITERAL ("a") | a | Whole string matches |
| Or | LITERAL ("a") OR LTIERAL ("b") | a|b | a or b |
| Subroutine * | SUBROUTINE("test") | Matches a predefined group |
* Custom implementation, this feature is not a part of the default regex engine for ecmascript
Flags are used to set the modes in the RegExp parser
| Name | Usage | Description |
|---|---|---|
| Global | GLOBAL | Does not stop after first match |
| Multiline | MULTILINE | ^ and $ match the start and end of the line |
| Case insensitive | CASE INSENSITIVE | Matches capital letters and non-captial letters as the same |
| Single line | SINGLE LINE | Reads whole input as one line |
| Unicode | UNICODE | Strings will be treated as UTF-16 |
| STICKY | STICKY | Forces pattern to anchor at start of the search or the last match |
* Also called "Ignore Whitespace"