Luddite Reference

Luddite is the language Komodo uses for user-defined syntax highlighting and multi-language lexing. An introduction to the Luddite language can be found in the User-Defined Language Support documentation.

Keywords

The following is a list of Luddite keywords - not to be confused with the keywords described by the UDL file itself for the target language definition. The Luddite keyword is always given followed by its argument list, where applicable; optional arguments are given in square brackets ([ ... ]).

accept name-or-string-list | all

Used in token_check definitions to disambiguate characters. If all is specified, then a token_check test will always succeed. If the previous token falls in the name-or-string list, the token_check test succeeds. Otherwise Luddite will look at the results of any skip and reject statements in the current family to decide which action to take.

all

Used in accept, reject, and skip statements in token_check definitions. This means that the token_check test will follow whatever directive is associated with this occurrence of all.

at_eol(state-name)

Used to specify the Luddite state to transition to when the end of the current line is reached. This is useful for processing languages like the Perl-based template language, Mason, in which one can embed Perl code on a single line by putting a '%' character at the start of the line, as in this example:

  Good
  % if ($time > 12) {
  afternoon
  % } else {
  morning
  % }

This is easily handled with this Luddite code:

  state IN_M_DEFAULT:
  /^%/ : paint(upto, M_DEFAULT), paint(include, TPL_OPERATOR), \
    at_eol(IN_M_DEFAULT), => IN_SSL_DEFAULT

If there's a percent character at the start of a line in markup mode, cause it to be lexed as a template operator, and switch to Perl lexing (IN_SSL_DEFAULT), and switch back to markup-based lexing when it reaches the end of the line.

clear_delimiter

Used in conjunction with keep_delimiter, this action explicitly clears the current delimiter (useful in recognizing terminating identifiers in here documents).

delimiter

Used in place of a pattern or match-string in transitions, this will succeed if there's a current delimiter defined, and it can be matched at the current point in the buffer. When it's matched, the current delimiter will be unset, unless the keep_delimiter action is given in the transition.

family csl | markup | ssl | style | tpl

The sub-type of this sub-language. The meaning of each family name is:

csl

client-side language (e.g. usually JavaScript)

markup

markup language (e.g. HTML, XHTML, other XML dialects)

ssl

server-side language (e.g. Perl, Python, Ruby)

style

stylesheet language (usually CSS)

tpl

a "template-oriented" language, usually geared to either adding template-side processing to the server-side language, or making it easier to inject the server-side language into other parts of the full multi-language document, as in CSS or JS. Examples include Smarty for PHP processing.

fold "name-or-string" style +|-

Used to describe which tokens start and end a code-folding block. For example:

  fold "{" CSL_OPERATOR +
  fold "if" SSL_WORD +
  fold "end" SSL_WORD -

keep_delimiter

Used when the delimiter directive was used in place of a pattern or string, this tells the UDL lexer to retain that directive for subsequent matching. This is useful for matching a construct like Perl's s,/,\\, construct, where we would be using ',' as the regex delimiter, instead of the normal '/'.

keywords name-or-string-list

List the words that should be colored as keywords (as opposed to identifiers) in the defined language. Keywords for the target language that are the same as reserved words in Luddite must be quoted.

  keywords ["en-US\luddite.html", "193", BEGIN, class ensure nil ]

keyword_style style-name => style-name

This directive works with keywords to tell UDL which identifier-type style needs to be promoted to a keyword style. So all tokens listed in keywords that are colored as the first style normally will be promoted to the second style.

  keyword_style SSL_IDENTIFIER => SSL_WORD

include [path/]file

Include a UDL file. The include path starts with the current directory; if you include a file in a different directory, that file's directory is appended to the include path.

  include "html2ruby.udl"

include

When used as an argument to the paint keyword, include a style.

initial state-name

The state processing for the current family should start at.

  initial IN_SSL_DEFAULT

language name

The name of the language being defined. The language directive must be given. It may be given more than once, but only with the same value is given each time. This value shows up in the Komodo UI in places like Language Preferences and the "New File" command.

  language RHTML

namespace XML Namespace identifier

The namespace declaration tells Komodo to load the language service described by the current Luddite program when it sees an XML file that uses the specified namespace as a default attribute value.

  namespace "http://www.w3.org/2001/XMLSchema"
  namespace "http://www.w3.org/1999/XMLSchema"
  # Be prepared if a new version is released in a few centuries.
  namespace "http://www.w3.org/2525/XMLSchema"

no_keyword

The no_keyword command is used to prevent identifier => keyword promotion when an identifier is recognized. This is useful for programming languages that allow any token, even keywords, to be used in certain contexts, such as after the "." in Python, Ruby, and VBScript, or after "::" or "->" in Perl.

  state IN_SSL_DEFAULT:
  /\.(?=[a-z])/ : paint(upto, SSL_DEFAULT), \
    paint(include, SSL_OPERATOR), => IN_SSL_NON_KEYWORD_IDENTIFIER_1

  state IN_SSL_NON_KEYWORD_IDENTIFIER_1:
  /[^a-zA-Z0-9_]/ : paint(upto, SSL_IDENTIFIER), redo, no_keyword, \
    => IN_SSL_DEFAULT

paint(include|upto, style-name)

These directives are used in state transitions, and are key to the way UDL generates lexers. They appear in a context like this:

  state IN_SSL_COMMENT_1 :
  /$/ : paint(include, SSL_COMMENT) => IN_SSL_DEFAULT

This means that when we're in a state with name "IN_SSL_COMMENT_1" (remember that state names are completely arbitrary in your Luddite programs), and we find the end of the line, we should paint everything from the last "paint point" to the end of the line with the style "SCE_UDL_SSL_COMMENT". This will also move the paint-point to the point after the last character this command styles.

A transition can have a paint(include...) command, a paint(upto...) command, both of them, or neither.

pattern name = string

These are used as macro substitution inside patterns used in state tables. The names should contain only letters, and are referenced in patterns and the right-hand side of Luddite patterns by putting a "$" before them.

  pattern NMSTART = '_\w\x80-\xff' # used inside character sets only
  pattern NMCHAR = '$NMSTART\d'    # used inside character sets only
  ...
  state IN_SSL_SYMBOL_1:
  /[$NMCHAR]+/ : paint(include, SSL_STRING), => IN_SSL_DEFAULT

public_id DOCTYPE public identifier

The public_id declaration tells Komodo to load the language service described by the current Luddite program when it sees an XML or SGML file that uses the specified public declaration in its Doctype declaration.

  public_id "-//MOZILLA//DTD XBL V1.0//EN"
  publicid "-//MOZILLA//DTD XBL V1.1//EN" # Be prepared
  # "publicid" is a synonym for "public_id"

redo

The redo command indicates that the lexer should not advance past the current characters being matched, but should stay there in the new state.

  state IN_SSL_NUMBER_3:
  ...
  /[^\d]/ : paint(upto, SSL_NUMBER), redo, => IN_SSL_DEFAULT

This specifies that when we're processing numbers (assuming the arbitrary name "IN_SSL_NUMBER_3" reflects the idea that we're trying to recognize numeric terms in the input), and find a non-digit, we should paint everything up to but not including the start of the matched text with the SCE_UDL_SSL_NUMBER style, change to the default state for this family, and retry lexing the same character.

Since having both a redo action and a paint(include...) action in the same transition would be contradictory, the Luddite compiler gives an error message when it detects this condition and stops processing.

reject name-or-string-list | all

Used in token_check definitions to disambiguate characters. If all is specified, then a token_check test will always fail. If the previous token falls in the name-or-string list, the token_check test fails. Otherwise Luddite will look at the results of any reject and skip statements in the current family to decide which action to take.

set_delimiter (number)

This transition action takes a single argument, which must be a reference to a grouped sub-pattern in the transition's pattern. It sets the current delimiter to that contents of the subpattern.

  /m([^\w\d])/ : paint(upto, SSL_DEFAULT), set_delimiter(1), \
    => IN_SSL_REGEX1_TARGET

set_opposite_delimiter (number)

This transition action takes a single argument, which must be a reference to a grouped sub-pattern in the transition's pattern. It sets the current delimiter to that contents of the subpattern.

  /m([\{\[\(\<])/ : paint(upto, SSL_DEFAULT), \
    set_opposite_delimiter(1), => IN_SSL_REGEX1_TARGET

skip name-or-string-list | all

Used in token_check definitions to disambiguate characters. If all is specified, then a token_check test will retry with the token preceding this one. If the previous token falls in the name-or-string list, the token_check test keeps going. Otherwise Luddite will look at the results of any accept and reject statements in the current family to decide which action to take.

state state-name: transition-list

The core of Luddite programs. Each state block is in effect upto the next Luddite keyword.

sublanguage name

The common name of the language this family targets.

  sublanguage ruby

sub_language

Synonym for sublanguage

system_id DOCTYPE system identifier

The system_id declaration tells Komodo to load the language service described by the current Luddite program when it sees an XML or SGML file that uses the specified system declaration in its Doctype declaration.

  
  system_id "http://www.w3.org/2001/XMLSchema"
  systemid "http://www.w3.org/1999/XMLSchema"
  # "systemid" is a synonym for "system_id"

token_check: token-recognition-list

A set of directives that define the token checking set for this family.

Used in state transitions immediately after a pattern or string (match target) is given. This is used for token disambiguation. For example in Ruby, Perl, and JavaScript, a '/' can either be a division operator or the start of a regular expression. By looking at how the previous token was styled, we can determine how to interpret this character.

If the token_check test fails, the pattern is deemed to fail, and UDL tries subsequent transitions in the state block.

start_style style-name

The lowest style in the list of styles Luddite will use for this family (in terms of the values given in Scintilla.iface). This is used for token_check processing while lexing, so it's not required otherwise.

end_style

The highest style in the list of styles Luddite will use for this family (in terms of the values given in Scintilla.iface). This is used for token_check processing while lexing, so it's not required otherwise.

upto

See paint

spop_check

See spush_check

spush_check(state-name)

Used to specify the Luddite state to transition to at a later point.

  state IN_SSL_DSTRING:
  '#{' : paint(include, SSL_STRING), spush_check(IN_SSL_DSTRING), \
    => IN_SSL_DEFAULT
  ...
  state IN_SSL_OP1:
  '{' : paint(include, SSL_OPERATOR), spush_check(IN_SSL_DEFAULT) \
    => IN_SSL_DEFAULT
  ...
  state IN_SSL_DEFAULT:
  '}' : paint(upto, SSL_DEFAULT), paint(include, SSL_OPERATOR), \
    spop_check, => IN_SSL_DEFAULT

This code is used to account for the way the Ruby lexer is intended to color expressions inside #{...} brackets in strings as if they weren't in strings. When the "}" is reached, the lexer needs to know whether it should go back to lexing a string, or to the default state. We use the spush_check and spop_check directives to specify this.