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Custom Lexers for C::B? (Was: XML file types?)

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rickg22:
Recently i've been glimpsing over the scintilla code, and i've seen that there's html support in scintilla. And I think code folding, too!

So, what needs to be done to add XML / HTML support to the codeblocks editor?

Actually, what needs to be done to add other (custom) filetypes to the editor?

per_eckerdal:
Yes, it would be very neat with Python (for SCons) and PHP support :)

I could help developing support for more file types (not until august tho)
/Per Eckerdal

mandrav:
I plan on writing proper documentation for this feature, but here are some *rough* info:

The files that add syntax highlighting support for specific files are found under sd/resources/lexers. They 're simple XML files named as lexer_*.xml.
Let's take lexer_cpp.xml as an example and disect it.


--- Code: --- <Lexer name="C/C++"
index="3"
filemasks="*.c,*.cpp,*.cc,*.cxx,*.h,*.hpp,*.hh,*.hxx,*.inl">
--- End code ---

Pretty much self explanatory, except for the "magic" index number (we 'll come to it in a sec).
The name is the lexer's configuration name. This will appear in the editor's configuration dialog, in the languages drop down box (in colors editing page).
The filemasks is a comma separated list of the extensions that this lexer should be used for. This is case-insensitive.
The index corresponds with the wxSTC_LEX_* constants, found in wx/stc/stc.h. In this example, if you look in wx/stc/stc.h, you 'll see that index 3 matches wxSTC_LEX_CPP. The lexer id for C/C++ syntax highlighting :)
If we were building a lexer configuration for, say, XML (random choice ;) ) we would look up the constant wxSTC_LEX_XML which is defined to be number 5. So index=5. Simple :)

Next follows many <Style> tags defining the different styles:

--- Code: --- <Style name="Default"
index="0"
fg="0,0,0"
bg="255,255,255"
bold="0"
italics="0"
underlined="0"/>
--- End code ---

Name is the style's name. It appears in the editor's configuration dialog, in the colors editing page.
fg is the foreground color. Comma separated list of three numbers from 0 to 255. In order: red, green and blue (RGB).
bg is the background color.
bold is "0" for disabled, "1" for enabled. Same goes for italics and underlined.
You don't have to define all of these attributes. It's good to define them all for the "default" style (all lexers have a default style), but only the attributes needed should be defined for the rest of the styles.

The index number in the <Style> tags, comes from a different set of constants defined in wx/stc/stc.h. For each language supported by scintilla, there is a set of styles defined (these are what we 're trying to configure with these files). For example, for C/C++ files (wxSTC_LEX_CPP, remember?) the styles are defined as wxSTC_C_*.
For the "default" style shown above, this would be wxSTC_C_DEFAULT which is defined to be 0. Hence index=0 for "default".

--- Code: --- <Style name="Comment (normal)"
index="1,2"
fg="160,160,160"/>
--- End code ---

This is the style definition for normal comments. As you can see you can define a single style for more than one style index, in this case two: 1 and 2 (always comma separated).
1 is for wxSTC_C_COMMENT (the C comment /* */) and 2 is for wxSTC_C_COMMENTLINE (the C++ comment to end of line // ).

I just want to add that there are some special styles defined by Code::Blocks and are available to all lexers:

Index -99: the selected text style
Index -98: the active line style (the line the caret is on)
Index -2 : the breakpoint line style
Index -3 : the debugger active line style (while stepping the debugger)
Index -4 : the compiler warning/error line style

Now on to the keywords.
If the language you 're defining a lexer configuration for, has keywords they should be added in the <Keywords> tag. This tag can contain the following tags:
<Language>, <User> and <Documentation>
Language contains the language keywords. These are usually at index 0.
User is not used right now but might be in the future.
Documentation contains the documentation keywords (if any). If you look at the lexer_cpp.xml file, you 'll see that the documentation keywords defined are those of doxygen.


Whew, that was kind of long! I just hope it makes more sense now.

Yiannis.

PS: do you think it should be wiki'ed ?

rickg22:
Yes, definitely! :D By the way, you didn't mention XML code folding, which is the feature I asked for in the RFE in question. Any more info on this feature in particular, if it exists? (Like, opening and closing the contents of an xml element/tag or comment)

mandrav:

--- Quote ---By the way, you didn't mention XML code folding
--- End quote ---

Make a lexer configuration for XML files and see if it does :)
I mean, folding is a scintilla feature and Code::Blocks turns it on. It's just a matter of the lexer supporting it (I guess all lexers do).

Yiannis.

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