snippet.md

Tabstops

With tabstops you can make the editor cursor move inside a snippet. Use $1, $2 to specify cursor locations. The number is the order in which tabstops will be visited, whereas $0 denotes the final cursor position. Multiple tabstops are linked and updated in sync.

Placeholders

Placeholders are tabstops with values, like ${1:foo}. The placeholder text will be inserted and selected such that it can be easily changed. Placeholders can nested, like ${1:another ${2:placeholder}}.

Choice

Placeholders can have choices as values. The syntax is a comma-separated enumeration of values, enclosed with the pipe-character, e.g. ${1|one,two,three|}. When inserted and selected choices will prompt the user to pick one of the values.

Variables

With $name or ${name:default} you can insert the value of a variable. When a variable isn't set its default or the empty string is inserted. When a variable is unknown (that is, its name isn't defined) the name of the variable is inserted and it is transformed into a placeholder. The following variables can be used:

• TM_SELECTED_TEXT The currently selected text or the empty string

• TM_CURRENT_LINE The contents of the current line

• TM_CURRENT_WORD The contents of the word under cursor or the empty string

• TM_LINE_INDEX The zero-index based line number

• TM_LINE_NUMBER The one-index based line number

• TM_FILENAME The filename of the current document

• TM_FILENAME_BASE The filename of the current document without its extensions

• TM_DIRECTORY The directory of the current document

• TM_DIRECTORY_BASE The base directory name of the current document

• TM_FILEPATH The full file path of the current document

• RELATIVE_FILEPATH The relative (to the opened workspace or folder) file path of the current document

• CLIPBOARD The contents of your clipboard

• WORKSPACE_NAME The name of the opened workspace or folder

• WORKSPACE_FOLDER The path of the opened workspace or folder

For inserting the current date and time:

• CURRENT_YEAR The current year

• CURRENT_YEAR_SHORT The current year's last two digits

• CURRENT_MONTH The month as two digits (example '02')

• CURRENT_MONTH_NAME The full name of the month (example 'July')

• CURRENT_MONTH_NAME_SHORT The short name of the month (example 'Jul')

• CURRENT_DATE The day of the month

• CURRENT_DAY_NAME The name of day (example 'Monday')

• CURRENT_DAY_NAME_SHORT The short name of the day (example 'Mon')

• CURRENT_HOUR The current hour in 24-hour clock format

• CURRENT_MINUTE The current minute

• CURRENT_SECOND The current second

• CURRENT_SECONDS_UNIX The number of seconds since the Unix epoch

For inserting random values:

• RANDOM 6 random Base-10 digits

• RANDOM_HEX 6 random Base-16 digits

• UUID A Version 4 UUID

Variable-Transform

Transformations allow to modify the value of a variable before it is being inserted. The definition of a transformation consists of three parts:

1. A regular expression that is matched against the value of a variable, or the empty string when the variable cannot be resolved.

2. A "format string" that allows to reference matching groups from the regular expression. The format string allows for conditional inserts and simple modifications.

3. Options that are passed to the regular expression

The following sample inserts the name of the current file without its ending, so from foo.txt it makes foo.

${TM_FILENAME/(.*)\..+$/$1/}
  |           |         | |
  |           |         | |-> no options
  |           |         |
  |           |         |-> references the contents of the first
  |           |             capture group
  |           |
  |           |-> regex to capture everything before
  |               the final `.suffix`
  |
  |-> resolves to the filename

Placeholder-Transform

Like a Variable-Transform, a transformation of a placeholder allows changing the inserted text for the placeholder when moving to the next tab stop. The inserted text is matched with the regular expression and the match or matches - depending on the options - are replaced with the specified replacement format text. Every occurrence of a placeholder can define its own transformation independently using the value of the first placeholder. The format for Placeholder-Transforms is the same as for Variable-Transforms.

The following sample removes an underscore at the beginning of the text. _transform becomes transform.

${1/^_(.*)/$1/}
  |   |    |  |-> No options
  |   |    |
  |   |    |-> Replace it with the first capture group
  |   |
  |   |-> Regular expression to capture everything after the underscore
  |
  |-> Placeholder Index

Grammar

Below is the EBNF for snippets.

any         ::= tabstop | placeholder | choice | variable | text
tabstop     ::= '$' int
                | '${' int '}'
                | '${' int  transform '}'
placeholder ::= '${' int ':' any '}'
choice      ::= '${' int '|' text (',' text)* '|}'
variable    ::= '$' var | '${' var }'
                | '${' var ':' any '}'
                | '${' var transform '}'
transform   ::= '/' regex '/' (format | text)+ '/' options
format      ::= '$' int | '${' int '}'
                | '${' int ':' '/upcase' | '/downcase' | '/capitalize' | '/camelcase' | '/pascalcase' | '/kebabcase' | '/snakecase' '}'
                | '${' int ':+' if '}'
                | '${' int ':?' if ':' else '}'
                | '${' int ':-' else '}' | '${' int ':' else '}'
regex       ::= JavaScript Regular Expression value (ctor-string)
options     ::= JavaScript Regular Expression option (ctor-options)
var         ::= [_a-zA-Z] [_a-zA-Z0-9]*
int         ::= [0-9]+
text        ::= .*

Escaping is done with with the \ (backslash) character. The rule of thumb is that you can escape characters that otherwise would have a syntactic meaning, e.g within text you can escape $, } and \, within choice elements you can escape |, , and \, and within transform elements you can escape / and \. Also note that in JSON you need to escape \ as \\.