dex-syntax (7) - Linux Manuals
Syntax of syntax highlighting files used by dex.
DESCRIPTIONSyntax file consists of states. A state consists of optional conditionals and one default action. The best way understand the syntax is to read /usr/share/dex/syntax/dex (a simple example) or /usr/share/dex/syntax/c (a more complete example using sub-syntaxes).
Basic syntax of the syntax files is the same used in the rc files, but the available commands are different.
Main commandssyntax <name>
- Begin a new syntax. One syntax file can contain multiple syntax definitions, but you should only define one real syntax in one syntax file.
- See also SUB-SYNTAXES.
state <name> [emit-color]
- Add new state. Conditionals (if any) and one default action must follow. First state is the start state.
default <color> <name>...
- Set default color for emitted name.
- default numeric oct dec hex
- If there is no color defined for oct, dec or hex then color numeric is used instead.
list [-i] <name> <string>...
- Define a list of strings.
- list keyword if else for while do continue switch case
- Use conditional inlist to test if a buffered string is in a list.
-i Make list case-insensitive.
Conditionalsbufis [-i] <string> <destination> [emit-name]
- Test if buffered bytes are same as string. If they are emit emit-name and jump to destination state.
char [-bn] <characters> <destination> [emit-name]
- Test if current byte is in the character list. If it is then emit emit-color and jump to destination state. If emit-name is not given then destination states emit name is used.
- Characters is a list of strings. Ranges are supported (a-d is same as abcd).
- -b Add byte to buffer.
- -n Invert character bitmap.
- Compare following characters to heredoc end delimiter and go to destination state if comparison is true.
inlist <list> <destination> [emit-name]
- Test if buffered bytes are found in list. If found emit emit-name and jump to destination state.
str [-i] <string> <destination> [emit-name]
- See if following bytes are same as string. If they are emit emit-name and jump to destination state.
- -i case-insensitive.
- NOTE: This conditional can be slow, especially if string is longer than two bytes.
Default actionsLast command of every state must be default action. It is an unconditional jump.
eat <destination> [emit-name]
- Consume byte, emit emit-name color and continue to destination state.
heredocbegin <subsyntax> <return-state>
- Store buffered bytes as heredoc end delimiter and go to subsyntax. Subsyntax is like any other subsyntax but it must contain heredocend conditional.
noeat [-b] <destination>
- Continue to destination state without emitting color or consuming byte.
- -b Don't stop buffering.
Other commandsrecolor <color> [count]
- If count is given, recolor count previous bytes, otherwise recolor buffered bytes.
SUB-SYNTAXESSub-syntaxes are useful when same states are needed in many contexts.
Sub-syntax name must be prefixed with ".". It is recommended to also use main syntax's name in the prefix. For example ".c-comment" if "c" is the main syntax.
Sub-syntax is a syntax of which some destination state's name is END. END is a special state name which is replaced by state given at another syntax.
char "*" star
- char "*" star
state star comment
# END is a special state name
char / END comment
- # END is a special state name
# main syntax
state c code
char " \t\n" c
char -b a-zA-Z_ ident
char "\"" string
char "'" char
# call sub-syntax
str "/*" .c-comment:c
- char " \t\n" c
- # other states removed
In this example the destination state .c-comment:c is special syntax for calling a sub-syntax. ".c-comment" is name of the sub-syntax and "c" is the return state defined in the main syntax. Whole sub-syntax tree is copied into the main syntax and all destination states in the sub-syntax whose name is END are replaced with "c".
AUTHORSTimo Hirvonen <tihirvon [at] gmail.com>