Code Completion and Content Assist

Content Assist

Content Assist is a general concept encompassing:

• Code completion,
• Text hover, and
• Contextual information.

All of these features are supported by SchemeScript.

How this works

At startup time, SchemeScript populates a dictionary (symbol table) with all the top-level definitions found in all Scheme source files found in the current workspace (files with the extension .scm). This dictionary contains information on the source location of the various definitions, a description of the definition (is it a variable? a function? syntax? etc.).

Also, each time a file is saved, the dictionary is updated to reflect the changes.

Customization

The set of top-level forms that are recognized by the editor for content assist purposes can be adapted to the user's needs. By default, all Scheme forms are recognized, as well as some Kawa extensions, like module forms, class definitions, record (SRFI-9) definitions, etc.

To add (or remove) forms supported, the file conf/forms.scm, found in the plug-in directory, must be edited.

To add a supported form, simply add a call to the SchemeScript function define-form-processor. The first argument must be a symbol (the name of the supported form), while the second argument is a lambda-expression called to process top-level forms beginning with the specified symbol. This lambda-expression must accept 4 parameters (the dictionary, the matched form, the Eclipse resource containing the form, and the line number of the form), and is responsible for populating the dictionary by calling the add-entry! procedure (defined at the beginning of conf/forms.scm).

Here is an example for the define-syntax special form:

(define-form-processor
 'define-syntax
 (lambda (dictionary form resource line-number)
   (when (and (pair? (cdr form))
              (symbol? (cadr form)))
     (let* ((name        (cadr form))
            (description (format #f "~a - user syntax" name)))
       (add-entry! dictionary name description 'syntax resource line-number)))))	

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