dte text editor

dte-syntax

A dte syntax file consists of multiple states. A state consists of optional conditionals and one default action. The best way understand the syntax is to read through some of the built-in syntax files, which can be printed with dte -b, for example:

dte -b syntax/dte

The basic syntax used is the same as in dterc files, but the available commands are different.

Conditionals and default actions have a destination state. The special destination state this can be used to jump to the current state.

Commands

Main commands

syntax 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. The first state is the start state.

default color name...

Set default color for emitted name.

Example:

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.

Example:

list keyword if else for while do continue switch case

Use the inlist command to test if a buffered string is in a list.

-i
Make list case-insensitive.

Conditionals

bufis [-i] string destination [emit-name]

Test if buffered bytes are same as string. If they are, emit emit-name and jump to destination state.

-i
Case-insensitive.

char [-bn] characters destination [emit-name]

Test if current byte is in the characters list. If it is then emit emit-color and jump to destination state. If emit-name is not given then the destination state's emit name is used.

characters is a list of strings. Ranges are supported (a-d is the same as abcd).

-b
Add byte to buffer.
-n
Invert character bitmap.

heredocend destination

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 actions

The last command of every state must be a 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. Sub-syntax is like any other sub-syntax but it must contain a heredocend conditional.

noeat [-b] destination

Continue to destination state without emitting color or consuming byte.

-b
Don't stop buffering.

Other commands

recolor color [count]

If count is given, recolor count previous bytes, otherwise recolor buffered bytes.

Sub-syntaxes

Sub-syntaxes are useful when the same states are needed in many contexts.

Sub-syntax names must be prefixed with .. It's recommended to also use the main syntax name in the prefix. For example .c-comment if c is the main syntax.

A sub-syntax is a syntax in which some destination state's name is END. END is a special state name that is replaced by the state specified in another syntax.

Example:

In this example the destination state .c-comment:c is a special syntax for calling a sub-syntax. .c-comment is the name of the sub-syntax and c is the return state defined in the main syntax. The 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.