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Processing Instructions

Processing instructions provide document-level configuration, overriding application configuration for a specific document.

Syntax

<?scryber parser-mode='Strict' parser-log='false' append-log='false' 
         log-level='Warnings' controller='MyNamespace.MyController, MyAssembly' 
         parser-culture='en-GB' ?>

Supported Attributes

Attribute Type Values Description
parser-mode enum Strict, Lax Strict throws on invalid elements; Lax ignores them
parser-log bool true, false Enable parser trace output
append-log bool true, false Append trace log to PDF document
log-level enum Off, Errors, Warnings, Messages, Verbose, Diagnostic Minimum log level
parser-culture string Culture code e.g., en-GB, fr-FR - affects number/date parsing
controller string Assembly-qualified type name Document controller class

Examples

Basic Parser Configuration

<?scryber parser-mode='Lax' log-level='Warnings' ?>

With Controller

<?scryber parser-mode='Strict' 
          controller='MyCompany.Reports.SalesController, MyCompany.Reports' ?>

Development Mode

<?scryber parser-mode='Strict' 
          parser-log='true' 
          append-log='true' 
          log-level='Verbose' ?>

Localized Document

<?scryber parser-culture='fr-FR' ?>

Implementation Details

Processing Instruction Parsing

Parser implementation in XMLParser.ParseProcessingInstructions():

// Scryber.Generation/XMLParser.cs
protected void ParseProcessingInstructions(XmlReader reader, string name)
{
    string value = reader.Value;
    this.Settings.ReadProcessingInstructions(value);
    
    LogAdd(reader, TraceLevel.Message, 
        "Parsed processing instructions. Controller = {5}, parser mode = {1}, logging = {2}, append-log = {3}, log-level = {4}", 
        value, this.Mode, this.Settings.LogParserOutput, 
        this.Settings.AppendLog, this.Settings.TraceLog.RecordLevel, 
        this.Settings.ControllerType == null ? "[NONE]" : this.Settings.ControllerType.ToString());
}

Use Cases

1. Production Document (Lax Mode)

<?scryber parser-mode='Lax' log-level='Errors' ?>
<html xmlns='http://www.w3.org/1999/xhtml'>
    <!-- Skips invalid elements, but logs everything. -->
</html>

2. Development Document (Strict Mode with Logging)

<?scryber parser-mode='Strict' 
          parser-log='true' 
          append-log='true' 
          log-level='Messages' ?>
<html xmlns='http://www.w3.org/1999/xhtml'>
    <!-- Throws exception on any invalid element, and logs document execution.-->
</html>

3. Controller-Based Document

<?scryber controller='MyCompany.Reports.InvoiceController, MyCompany.Reports' ?>
<html xmlns='http://www.w3.org/1999/xhtml'>
    <body on-init='InitInvoice' on-load='LoadData'>
        <main>
            <span id='CustomerLabel' />
        </main>
    </body>
</html>

4. Localized Document

<?scryber parser-culture='de-DE' ?>
<html xmlns='http://www.w3.org/1999/xhtml'>
    <!-- Numbers formatted as 1.234,56 in template content -->
    <!-- Dates formatted as 31.12.2025 in template content -->
</html>

**NOTE:** Content bound to values within the document will be parsed under the current ThreadCulture, the parser culture is purely for fixed values within the template.

Parser Modes

Using Lax in production, and strict in development means that end users will not face errors that have been missed. And will at least receive the document they requested.

Strict Mode

  • Throws exceptions on unrecognized elements or attributes
  • Enforces valid structure according to component definitions
  • Recommended for production - catches errors early
  • Use when: Template structure is stable and tested
<?scryber parser-mode='Strict' ?>

Lax Mode

  • Ignores unrecognized elements and attributes
  • Logs warnings instead of throwing exceptions
  • Continues parsing despite errors
  • Use when: Developing templates, gradual migration, forward compatibility
<?scryber parser-mode='Lax' ?>

Log Levels

Level Description Use Case
Off No logging Production, performance-critical
Errors Errors only Production with error tracking
Warnings Errors and warnings Default production level
Messages Info messages Development, debugging
Verbose Detailed execution Detailed debugging
Diagnostic Everything including performance, positioning and structure Performance analysis

Best Practices

Production Documents

<?scryber parser-mode='Lax' log-level='Errors' ?>

Development Documents

<?scryber parser-mode='Strict' parser-log='true' log-level='Messages' ?>

Debugging Documents

<?scryber parser-mode='Lax' 
          parser-log='true' 
          append-log='true' 
          log-level='Verbose' ?>

Verbose provides a high level of detail to identify what issues have occured without the significant performance drain or Diagnostic, which should only be used in extraneous circumstances.

Localized Documents

<?scryber parser-culture='en-GB' log-level='Warnings' ?>

Programmatic Configuration

Processing instructions can also be set programmatically:

var settings = new ParserSettings(/* ... */);
settings.ConformanceMode = ParserConformanceMode.Strict;
settings.LogParserOutput = false;
settings.TraceLog.SetRecordLevel(TraceRecordLevel.Warnings);
settings.SpecificCulture = new CultureInfo("en-GB");
settings.ControllerType = typeof(MyController);

var doc = Document.ParseDocument(stream, ParseSourceType.DynamicContent, settings);