Zack Peterson Zack Peterson - 4 months ago 13
Javascript Question

Is there a lang-vb or lang-basic option for prettify.js from Google?

Visual Basic code does not render correctly with prettify.js from Google.

on Stack Overflow:

Partial Public Class WebForm1
Inherits System.Web.UI.Page

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'set page title
Page.Title = "Something"
End Sub

End Class


in Visual Studio...

Visual Basic in Visual Studio

I found this in the README document:


How do I specify which language my
code is in?

You don't need to specify the language
since prettyprint() will guess. You
can specify a language by specifying
the language extension along with the
prettyprint class like so:

<pre class="prettyprint lang-html">
The lang-* class specifies the language file extensions.
Supported file extensions include
"c", "cc", "cpp", "cs", "cyc", "java", "bsh", "csh", "sh",
"cv", "py", "perl", "pl", "pm", "rb", "js",
"html", "html", "xhtml", "xml", "xsl".
</pre>



I see no lang-vb or lang-basic option. Does anyone know if one exists as an add-in?




Note: This is related to the VB.NET code blocks suggestion for Stack Overflow.

Answer

/EDIT: I've rewritten the whole posting.

Below is a pretty complete solution to the VB highlighting problem. If SO has got nothing better, please use it. VB syntax highlighting is definitely wanted.

I've also added a code example with some complex code literals that gets highlighted correctly. However, I haven't even tried to get XLinq right. Might still work, though. The keywords list is taken from the MSDN. Contextual keywords are not included. Did you know the GetXmlNamespace operator?

The algorithm knows literal type characters. It should also be able to handle identifier type characters but I haven't tested these. Note that the code works on HTML. As a consequence, &, < and > are required to be read as named (!) entities, not single characters.

Sorry for the long regex.

var highlightVB = function(code) {
    var regex = /("(?:""|[^"])+"c?)|('.*$)|#.+?#|(&amp;[HO])?\d+(\.\d*)?(e[+-]?\d+)?U?([SILDFR%@!#]|&amp;)?|\.\d+[FR!#]?|\s+|\w+|&amp;|&lt;|&gt;|([-+*/\\^$@!#%&<>()\[\]{}.,:=]+)/gi;

    var lines = code.split("\n");
    for (var i = 0; i < lines.length; i++) {
        var line = lines[i];

        var tokens;
        var result = "";

        while (tokens = regex.exec(line)) {
            var tok = getToken(tokens);
            switch (tok.charAt(0)) {
                case '"':
                    if (tok.charAt(tok.length - 1) == "c")
                        result += span("char", tok);
                    else
                        result += span("string", tok);
                    break;
                case "'":
                    result += span("comment", tok);
                    break;
                case '#':
                    result += span("date", tok);
                    break;
                default:
                    var c1 = tok.charAt(0);

                    if (isDigit(c1) ||
                        tok.length > 1 && c1 == '.' && isDigit(tok.charAt(1)) ||
                        tok.length > 5 && (tok.indexOf("&amp;") == 0 &&
                        tok.charAt(5) == 'H' || tok.charAt(5) == 'O')
                    )
                        result += span("number", tok);
                    else if (isKeyword(tok))
                        result += span("keyword", tok);
                    else
                        result += tok;
                    break;
            }
        }

        lines[i] = result;
    }

    return lines.join("\n");
}

var keywords = [
    "addhandler", "addressof", "alias", "and", "andalso", "as", "boolean", "byref",
    "byte", "byval", "call", "case", "catch", "cbool", "cbyte", "cchar", "cdate",
    "cdec", "cdbl", "char", "cint", "class", "clng", "cobj", "const", "continue",
    "csbyte", "cshort", "csng", "cstr", "ctype", "cuint", "culng", "cushort", "date",
    "decimal", "declare", "default", "delegate", "dim", "directcast", "do", "double",
    "each", "else", "elseif", "end", "endif", "enum", "erase", "error", "event",
    "exit", "false", "finally", "for", "friend", "function", "get", "gettype",
    "getxmlnamespace", "global", "gosub", "goto", "handles", "if", "if",
    "implements", "imports", "in", "inherits", "integer", "interface", "is", "isnot",
    "let", "lib", "like", "long", "loop", "me", "mod", "module", "mustinherit",
    "mustoverride", "mybase", "myclass", "namespace", "narrowing", "new", "next",
    "not", "nothing", "notinheritable", "notoverridable", "object", "of", "on",
    "operator", "option", "optional", "or", "orelse", "overloads", "overridable",
    "overrides", "paramarray", "partial", "private", "property", "protected",
    "public", "raiseevent", "readonly", "redim", "rem", "removehandler", "resume",
    "return", "sbyte", "select", "set", "shadows", "shared", "short", "single",
    "static", "step", "stop", "string", "structure", "sub", "synclock", "then",
    "throw", "to", "true", "try", "trycast", "typeof", "variant", "wend", "uinteger",
    "ulong", "ushort", "using", "when", "while", "widening", "with", "withevents",
    "writeonly", "xor", "#const", "#else", "#elseif", "#end", "#if"
]

var isKeyword = function(token) {
    return keywords.indexOf(token.toLowerCase()) != -1;
}

var isDigit = function(c) {
    return c >= '0' && c <= '9';
}

var getToken = function(tokens) {
    for (var i = 0; i < tokens.length; i++)
        if (tokens[i] != undefined)
            return tokens[i];
    return null;
}

var span = function(class, text) {
    return "<span class=\"" + class + "\">" + text + "</span>";
}

Code for testing:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    'set page title
    Page.Title = "Something"
    Dim r As String = "Say ""Hello"""
    Dim i As Integer = 1234
    Dim d As Double = 1.23
    Dim s As Single = .123F
    Dim l As Long = 123L
    Dim ul As ULong = 123UL
    Dim c As Char = "x"c
    Dim h As Integer = &amp;H0
    Dim t As Date = #5/31/1993 1:15:30 PM#
    Dim f As Single = 1.32e-5F
End Sub