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OpenType Layout Feature Code Editor
The OpenType Layout Feature Code Editor allows you to take full control over all the supported OpenType Layout Features in your font. Because adding features can be very time-consuming the editor uses a scripting language that is very easy to use and understand.
The OpenType editor supports a script-based syntax to define OpenType Layout Features for both Glyph Substitutions (GSUB) and Glyph Positioning (GPOS).
You can update and change the script at your convenience. The find and replace feature from the tool bar might be useful for this.
To test if the syntax is correct and all Glyph names are valid, select Compile in the Actions menu, use the shortcut key F9, or click the button on the toolbar. If there are any syntax errors or glyph names that could not be resolved, the Output window will list them. You can double-click on the error to quickly jump to the line where the error occurred.
If you want the compiler to ignore unknown glyphs, and allow empty classes and lookups, then click the warning icon in the toolbar.
When you click the OK button, the code will be compiled and on success will replace all your existing scripts, features, lookups, classes, and anchors.